[{"awards": "1841607 Banwell, Alison; 1841467 MacAyeal, Douglas", "bounds_geometry": "POLYGON((-68.28 -71.1,-68.202 -71.1,-68.124 -71.1,-68.046 -71.1,-67.968 -71.1,-67.89 -71.1,-67.812 -71.1,-67.734 -71.1,-67.656 -71.1,-67.578 -71.1,-67.5 -71.1,-67.5 -71.14999999999999,-67.5 -71.19999999999999,-67.5 -71.25,-67.5 -71.3,-67.5 -71.35,-67.5 -71.39999999999999,-67.5 -71.44999999999999,-67.5 -71.5,-67.5 -71.55,-67.5 -71.6,-67.578 -71.6,-67.656 -71.6,-67.734 -71.6,-67.812 -71.6,-67.89 -71.6,-67.968 -71.6,-68.046 -71.6,-68.124 -71.6,-68.202 -71.6,-68.28 -71.6,-68.28 -71.55,-68.28 -71.5,-68.28 -71.44999999999999,-68.28 -71.39999999999999,-68.28 -71.35,-68.28 -71.3,-68.28 -71.25,-68.28 -71.19999999999999,-68.28 -71.14999999999999,-68.28 -71.1))", "dataset_titles": "Dataset for: Banwell et al. 2024, \u0027Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica\u0027, Journal of Glaciology.", "datasets": [{"dataset_uid": "601771", "doi": "10.15784/601771", "keywords": "Antarctica; Antarctic Peninsula; AWS; Cryosphere; GNSS; GPS Data; Ice-Shelf Flexure; Ice Shelf Fracture; Ice-Shelf Melt; Timelaps Images", "people": "Stevens, Laura; Banwell, Alison; Willis, Ian; Dell, Rebecca; MacAyeal, Douglas", "repository": "USAP-DC", "science_program": null, "title": "Dataset for: Banwell et al. 2024, \u0027Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica\u0027, Journal of Glaciology.", "url": "https://www.usap-dc.org/view/dataset/601771"}], "date_created": "Thu, 15 Feb 2024 00:00:00 GMT", "description": "The evolution of surface and shallow subsurface meltwater across Antarctic ice shelves has important implications for their (in)stability, as demonstrated by the 2002 rapid collapse of the Larsen B Ice Shelf. It is vital to understand the causes of ice-shelf (in)stability because ice shelves buttress against the discharge of inland ice and therefore influence ice-sheet contributions to sea-level rise. Ice-shelf break-up may be triggered by stress variations associated with surface meltwater movement, ponding, and drainage. These variations may cause an ice shelf to flex and fracture. This four-year project will provide key geophysical observations to improve understanding of ice-shelf meltwater and its effects on (in)stability. The work will be conducted on the George VI Ice Shelf on the Antarctic Peninsula, where hundreds of surface lakes form each summer. Over a 27-month period, global positioning systems, seismometers, water pressure transducers, automatic weather stations, and in-ice thermistor strings will be deployed to record ice shelf flexure, fracture seismicity, water depths, and surface and subsurface melting, respectively, in and around several surface lakes on the George VI Ice Shelf, within roughly 20 km of the British Antarctic Survey\u0027s Fossil Bluff Station. Field data will be used to validate and extend the team\u0027s approach to modelling ice-shelf flexure and stress, and possible \"Larsen-B style\" ice-shelf instability and break-up. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -67.5, "geometry": "POINT(-67.89 -71.35)", "instruments": null, "is_usap_dc": true, "keywords": "ICE SHEETS; Antarctica; ICE MOTION; Ice-Shelf Flexure; GPS Data", "locations": "Antarctica", "north": -71.1, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Banwell, Alison; Macayeal, Douglas", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -71.6, "title": "NSFGEO-NERC: Ice-shelf Instability Caused by Active Surface Meltwater Production, Movement, Ponding and Hydrofracture", "uid": "p0010449", "west": -68.28}, {"awards": "2333940 Zhong, Shijie", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": null, "datasets": null, "date_created": "Mon, 08 Jan 2024 00:00:00 GMT", "description": "Satellite observations of Earth\u2019s surface gravity and elevation changes indicate rapid melting of ice sheets in recent decades in northern Antarctica Peninsula and Amundsen Sea Embayment of West Antarctica. This rapid melting may lead to significant global sea level rise which is a major societal concern. Measurements from the Global Positioning System (GPS) show rapid land uplift in these regions as the ice sheets melt. When an ice sheet melts, the melt water flows to oceans, causing global sea level to rise. However, the sea level change at a given geographic location is also influenced by two other factors associated with the ice melting process: 1) the vertical motion of the land and 2) gravitational attraction. The vertical motion of the land is caused by the change of pressure force on the surface of the solid Earth. For example, the removal of ice mass reduces the pressure force on the land, leading to uplift of the land below the ice sheet, while the addition of water in oceans increases the pressure force on the seafloor, causing it to subside. The sea level always follows the equipotential surface of the gravity which changes as the mass on the Earth\u2019s surface (e.g., the ice and water) or/and in its interiors (e.g., at the crust-mantle boundary) is redistributed. Additionally, the vertical motion of the land below an ice sheet has important effects on the evolution and stability of the ice sheet and may determine whether the ice sheet will rapidly collapse or gradually stabilize. The main goal of this project is to build an accurate and efficient computer model to study the displacement and deformation of the Antarctic crust and mantle in response to recent ice melting. The project will significantly improve existing and publicly available computer code, CitcomSVE. The horizontal and vertical components of the Earth\u2019s surface displacement depends on mantle viscosity and elastic properties of the Earth. Although seismic imaging studies demonstrate that the Antarctica mantle is heterogeneous, most studies on the ice-melting induced deformation in Antarctica have assumed that mantle viscosity and elastic properties only vary with the depth due to computational limitations. In this project, the new computational method in CitcomSVE avoids such assumptions and makes it possible to include realistic 3-D mantle viscosity and elastic properties in computing the Antarctica crustal and mantle displacement. This project will interpret the GPS measurements of the surface displacements in northern Antarctica Peninsula and Amundsen Sea Embayment of West Antarctica and use the observations to place constraints on mantle viscosity and deformation mechanisms. The project will also seek to predict the future land displacement Antarctica, which will lead to a better understand of Antarctica ice sheets. Finally, the project has direct implications for the study of global sea level change and the dynamics of the Greenland ice sheet. Technical Description Glacial isostatic adjustment (GIA) is important for understanding not only fundamental science questions including mantle viscosity, mantle convection and lithospheric deformation but also societally important questions of global sea-level change, polar ice melting, climate change, and groundwater hydrology. Studies of rock deformation in laboratory experiments, post-seismic deformation, and mantle dynamics indicate that mantle viscosity is temperature- and stress-dependent. Although the effects of stress-dependent (i.e., non-Newtonian) viscosity and transient creep rheology on GIA process have been studied, observational evidence remains elusive. There has been significant ice mass loss in recent decades in northern Antarctica Peninsula (NAP) and Amundsen Sea Embayment (ASE) of West Antarctica. The ice mass loss has caused rapid bedrock uplift as measured by GPS techniques which require surprisingly small upper mantle viscosity of ~1018 Pas. The rapid uplifts may have important feedback effects on ongoing ice melting because of their influence on grounding line migration, and the inferred small viscosity may have implications for mantle rheology and deformation on decadal time scales. The main objective of the project is to test hypotheses that the GPS observations in NAP and ASE regions are controlled by 3-D non-Newtonian or/and transient creep viscosity by developing new GIA modeling capability based on finite element package CitcomSVE. The project will carry out the following three tasks: Task 1 is to build GIA models for the NAP and ASE regions to examine the effects of 3-D temperature-dependent mantle viscosity on the surface displacements and to test hypothesis that the 3-D mantle viscosity improves the fit to the GPS observations. Task 2 is to test the hypothesis that non-Newtonian or/and transient creep rheology controls GIA process on decadal time scales by computing GIA models and comparing model predictions with GPS observations for the NAP and ASE regions. Task 3 is to implement transient creep (i.e., Burgers model) rheology into finite element package CitcomSVE for modeling the GIA process on global and regional scales and to make the package publicly available to the scientific community. The project will develop the first numerical GIA model with Burgers transient rheology and use the models to examine the effects of 3-D temperature-dependent viscosity, non-Newtonian viscosity and transient rheology on GIA-induced surface displacements in Antarctica. The project will model the unique GPS observations of unusually large displacement rates in the NAP and ASE regions to place constraints on mantle rheology and to distinguish between 3-D temperature-dependent, non-Newtonian and transient mantle viscosity. The project will expand the capability of the publicly available software package CitcomSVE for modeling viscoelastic deformation and tidal deformation on global and regional scales. The project will advance our understanding in lithospheric deformation and mantle rheology on decadal time scales, which helps predict grounding line migration and understand ice sheet stability in West Antarctica. The project will strengthen the open science practice by improving the publicly available code CitcomSVE at github. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "WAIS; CRUSTAL MOTION; COMPUTERS; GLACIER MASS BALANCE/ICE SHEET MASS BALANCE", "locations": "WAIS", "north": -60.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Zhong, Shijie", "platforms": "OTHER \u003e MODELS \u003e COMPUTERS", "repositories": null, "science_programs": null, "south": -90.0, "title": "Investigating Effects of Transient and Non-Newtonian Mantle Viscosity on Glacial Isostatic Adjustment Process and their Implications for GPS Observations in Antarctica", "uid": "p0010441", "west": -180.0}, {"awards": "2046437 Zitterbart, Daniel", "bounds_geometry": "POLYGON((-60 -55,-53 -55,-46 -55,-39 -55,-32 -55,-25 -55,-18 -55,-11 -55,-4 -55,3 -55,10 -55,10 -57.5,10 -60,10 -62.5,10 -65,10 -67.5,10 -70,10 -72.5,10 -75,10 -77.5,10 -80,3 -80,-4 -80,-11 -80,-18 -80,-25 -80,-32 -80,-39 -80,-46 -80,-53 -80,-60 -80,-60 -77.5,-60 -75,-60 -72.5,-60 -70,-60 -67.5,-60 -65,-60 -62.5,-60 -60,-60 -57.5,-60 -55))", "dataset_titles": null, "datasets": null, "date_created": "Mon, 16 Aug 2021 00:00:00 GMT", "description": "Part I: Non-technical description: Understanding human-induced changes on biodiversity is one of the most important scientific challenges we face today. This is especially true for marine environments that are home to much of the world\u2019s biomass and biodiversity. A particularly effective approach to investigate the effects of climate change on marine ecosystems is to monitor top-predator populations such as seabirds or marine mammals. The food web in the Southern Ocean in relatively small and involves few species, therefore climate-induced variations at the prey species level directly affect the predator species level. For example, seabirds, like penguins, are ideal to detect and study these ecosystem changes. This study combines traditional methods to study emperor penguin population dynamics with the use of an autonomous vehicle to conduct the population dynamic measurements with less impact and higher accuracy. This project leverages an existing long-term emperor penguin observatory at the Atka Bay colony which hosts penguins living in the Weddell sea and the Atlantic sector of the Southern Ocean. The study will kickstart the collection of a multi-decadal data set in an area of the Southern Ocean that has been understudied. It will fill important gaps in ecological knowledge on the state of the Emperor penguin and its adaptive capabilities within a changing world. Finally, the project supports NSF goals of training new generations of scientists through collaborative training of undergraduate students and the creation of a new class on robotics for ecosystem study. Emperor penguins are an iconic species that few people will ever see in the wild. Through the technology developed in this proposal, the public can be immersed in real-time into the life of an emperor penguin colony. Public outreach will be achieved by showcasing real-time video and audio footage of emperor penguins from the field as social media science and engineering-themed educational materials. Part II: Technical description: Polar ecosystems currently experience significant impacts due to global changes. Measurable negative effects on polar wildlife have already occurred, such as population decreases of numerous seabird species, including the complete loss of colonies of one of the most emblematic species of the Antarctic, the emperor penguin. These existing impacts on polar species are alarming, especially because many polar species still remain poorly studied due to technical and logistical challenges imposed by the harsh environment and extreme remoteness. Developing technologies and tools for monitoring such wildlife populations is, therefore, a matter of urgency. This project aims to help close major knowledge gaps about the emperor penguin, in particular about their adaptive capability to a changing environment, by the development of next-generation tools to remotely study entire colonies. Specifically, the main goal of this project is to implement and test an autonomous unmanned ground vehicle equipped with Radio-frequency identification (RFID) antennas and wireless mesh communication data-loggers to: 1) identify RFID-tagged emperor penguins during breeding to studying population dynamics without human presence; and 2) receive Global Positioning System-Time Domain Reflectometry (GPS-TDR) datasets from Very High Frequency VHF-GPS-TDR data-loggers without human presence to study animal behavior and distribution at sea. The autonomous vehicles navigation through the colony will be aided by an existing remote penguin observatory (SPOT). Properly implemented, this technology can be used to study of the life history of individual penguins, and therefore gather data for behavioral and population dynamic studies. The new data will contribute to intelligent establishment of marine protected areas in Antarctica. The education objectives of this CAREER project are designed to increase the interest in a STEM education for the next generation of scientists by combining the charisma of the emperor penguin with robotics research. Within this project, a new class on ecosystem robotics will be developed and taught, Robotics boot-camps will allow undergraduate students to remotely participate in Antarctic field trips, and an annual curriculum will be developed that allows K-12 students to follow the life of the emperor penguin during the breeding cycle, powered by real-time data obtained using the unmanned ground vehicle as well as the existing emperor penguin observatory. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 10.0, "geometry": "POINT(-25 -67.5)", "instruments": null, "is_usap_dc": true, "keywords": "AMD; Antarctica; Dronning Maud Land; FIELD SURVEYS; Amd/Us; Atka Bay; MARINE ECOSYSTEMS; USAP-DC; USA/NSF", "locations": "Atka Bay; Antarctica; Dronning Maud Land", "north": -55.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Zitterbart, Daniel", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS", "repositories": null, "science_programs": null, "south": -80.0, "title": "\r\nCAREER: Development of Unmanned Ground Vehicles for Assessing the Health of Secluded Ecosystems (ECHO)", "uid": "p0010245", "west": -60.0}, {"awards": "1443433 Licht, Kathy; 1443213 Kaplan, Michael", "bounds_geometry": "POLYGON((159 -83.8,159.5 -83.8,160 -83.8,160.5 -83.8,161 -83.8,161.5 -83.8,162 -83.8,162.5 -83.8,163 -83.8,163.5 -83.8,164 -83.8,164 -83.87,164 -83.94,164 -84.01,164 -84.08,164 -84.15,164 -84.22,164 -84.29,164 -84.36,164 -84.43,164 -84.5,163.5 -84.5,163 -84.5,162.5 -84.5,162 -84.5,161.5 -84.5,161 -84.5,160.5 -84.5,160 -84.5,159.5 -84.5,159 -84.5,159 -84.43,159 -84.36,159 -84.29,159 -84.22,159 -84.15,159 -84.08,159 -84.01,159 -83.94,159 -83.87,159 -83.8))", "dataset_titles": "10Be and 26Al cosmogenic nuclide surface exposure data; 3He input data", "datasets": [{"dataset_uid": "601375", "doi": "10.15784/601375", "keywords": "Antarctica; Cosmogenic Dating; Transantarctic Mountains", "people": "Winckler, Gisela; Schaefer, Joerg; Kaplan, Michael", "repository": "USAP-DC", "science_program": null, "title": "10Be and 26Al cosmogenic nuclide surface exposure data", "url": "https://www.usap-dc.org/view/dataset/601375"}, {"dataset_uid": "601376", "doi": "10.15784/601376", "keywords": "Antarctica; Transantarctic Mountains", "people": "Schaefer, Joerg; Winckler, Gisela; Kaplan, Michael", "repository": "USAP-DC", "science_program": null, "title": "3He input data", "url": "https://www.usap-dc.org/view/dataset/601376"}], "date_created": "Tue, 29 Sep 2020 00:00:00 GMT", "description": "Licht/1443433 Sediments deposited by the Antarctic ice sheet are an archive of its history with time and help geologists to determine how the remote interior of the ice sheet has changed over the past several hundred thousand years. This project will focus on the formation and dynamics of moraines (accumulations of dirt and rocks that are incorporated in the glacier surface or have been pushed along by the glacier as it moves) near the blue ice area of Mt. Achernar in the central Transantarctic Mountains in Antarctica.. The study will improve basic understanding of the formation of these moraines. Fieldwork at the site will focus on imaging the internal structure of the moraine to determine the processes by which it, and others like it, form over time. Additional analyses will include measurements of ice flow and collection of rock samples to determine the timing of debris deposition and the changes in the sources of sediments from deep within the Antarctic continent. The project will provide both graduate and undergraduate students training in paleoclimate studies, geology, and numerical modeling approaches. The broader impacts of the proposed work include hands on training in the Earth Sciences for graduate and undergraduate students, collaboration with colleagues in New Zealand and Sweden to provide an international research experience for students from the US, and three educational modules to be delivered by student researchers regarding Antarctica\u0027s role in global environments. The research is societally relevant and multidisciplinary and the topics are ideal for sharing with the public. All research findings will be made publicly available to others via timely publication in high-impact, peer-reviewed journals and all data will be submitted to the National Snow and Ice Data Center, and excess samples will be provided to the U.S. Polar Rock Repository. Direct observations of ice sheet history from the margins of Antarctica\u0027s polar plateau are essential for testing numerical ice sheet models, and the laterally extensive, blue-ice moraines of the Mt. Achernar Moraine complex in the central Transantarctic Mountains contain a unique and nearly untapped direct, quasi-continuous record of ice sheet change over multiple glacial cycles. The project objectives include improved understanding of processes and rates of blue ice moraine formation, as well as identifying the topographic, glaciological, and climatic controls on their evolution. Data to be collected with fieldwork in Antarctica include: imaging of internal ice structure with ground-penetrating radar, measurement of ice flow velocity and direction with a global positioning system (GPS) array, analysis of debris concentration and composition in glacier ice, state-of-the-art cosmogenic multi-nuclide analyses to determine exposure ages of moraine debris, mapping of trimlines and provenance analysis. Numerical model simulations, constrained by field data, will be used to evaluate the factors influencing changes in glacier flow that potentially impact the accumulation of the moraine debris. All together, the new data and modeling efforts will improve conceptual models of blue ice moraine formation, and thereby make them a more valuable proxy for developing a better understanding of the history of the ice sheet.", "east": 164.0, "geometry": "POINT(161.5 -84.15)", "instruments": null, "is_usap_dc": true, "keywords": "SEDIMENTS; GLACIAL PROCESSES; Mt. Achernar; ABLATION ZONES/ACCUMULATION ZONES; GLACIER ELEVATION/ICE SHEET ELEVATION; Antarctica; Antarctic Ice Sheet; Transantarctic Mountains; GLACIATION; USAP-DC; ICE MOTION; AMD; LABORATORY; Amd/Us", "locations": "Transantarctic Mountains; Antarctic Ice Sheet; Mt. Achernar; Antarctica", "north": -83.8, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Kaplan, Michael; Schaefer, Joerg; Winckler, Gisela; Licht, Kathy", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -84.5, "title": "Collaborative Research: Multidisciplinary Analysis of Antarctic Blue Ice Moraine Formation and their Potential as Climate Archives over Multiple Glacial Cycles", "uid": "p0010131", "west": 159.0}, {"awards": "1443126 MacAyeal, Douglas", "bounds_geometry": "POLYGON((166.1631 -77.9007,166.19736 -77.9007,166.23162 -77.9007,166.26588 -77.9007,166.30014 -77.9007,166.3344 -77.9007,166.36866 -77.9007,166.40292 -77.9007,166.43718 -77.9007,166.47144 -77.9007,166.5057 -77.9007,166.5057 -77.90423,166.5057 -77.90776,166.5057 -77.91129,166.5057 -77.91482,166.5057 -77.91835,166.5057 -77.92188,166.5057 -77.92541,166.5057 -77.92894,166.5057 -77.93247,166.5057 -77.936,166.47144 -77.936,166.43718 -77.936,166.40292 -77.936,166.36866 -77.936,166.3344 -77.936,166.30014 -77.936,166.26588 -77.936,166.23162 -77.936,166.19736 -77.936,166.1631 -77.936,166.1631 -77.93247,166.1631 -77.92894,166.1631 -77.92541,166.1631 -77.92188,166.1631 -77.91835,166.1631 -77.91482,166.1631 -77.91129,166.1631 -77.90776,166.1631 -77.90423,166.1631 -77.9007))", "dataset_titles": "McMurdo Ice Shelf AWS data; McMurdo Ice Shelf GPS survey of vertical motion; Supraglacial Lake Depths on McMurdo Ice Shelf, Antarctica; Time-lapse video of McMurdo Ice Shelf surface melting and hydrology", "datasets": [{"dataset_uid": "601107", "doi": "10.15784/601107", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPS; Ice Flow Velocity; Ice Shelf; Ice-Shelf Flexure; Snow/ice; Snow/Ice; Surface Melt", "people": "MacAyeal, Douglas; Banwell, Alison", "repository": "USAP-DC", "science_program": null, "title": "McMurdo Ice Shelf GPS survey of vertical motion", "url": "https://www.usap-dc.org/view/dataset/601107"}, {"dataset_uid": "601116", "doi": "10.15784/601116", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Shelf; Snow/ice; Snow/Ice; Subglacial And Supraglacial Water Depth; Supraglacial Lake; Supraglacial Meltwater; Water Depth", "people": "MacAyeal, Douglas; Banwell, Alison", "repository": "USAP-DC", "science_program": null, "title": "Supraglacial Lake Depths on McMurdo Ice Shelf, Antarctica", "url": "https://www.usap-dc.org/view/dataset/601116"}, {"dataset_uid": "601106", "doi": "10.15784/601106", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Hydrology; Ice Shelf; Snow/ice; Snow/Ice; Surface Hydrology; Surface Mass Balance; Weather Station Data", "people": "MacAyeal, Douglas; Banwell, Alison", "repository": "USAP-DC", "science_program": null, "title": "McMurdo Ice Shelf AWS data", "url": "https://www.usap-dc.org/view/dataset/601106"}, {"dataset_uid": "601113", "doi": "10.15784/601113", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Shelf; Photo/video; Photo/Video; Supraglacial Meltwater", "people": "Banwell, Alison; MacAyeal, Douglas", "repository": "USAP-DC", "science_program": null, "title": "Time-lapse video of McMurdo Ice Shelf surface melting and hydrology", "url": "https://www.usap-dc.org/view/dataset/601113"}], "date_created": "Tue, 24 Jul 2018 00:00:00 GMT", "description": "Meltwater lakes that sit on top of Antarctica\u0027s floating ice shelves have likely contributed to the dramatic changes seen in Antarctica\u0027s glacial ice cover over the past two decades. In 2002, the 1,600-square-kilometer Larsen B Ice Shelf located on the Eastern side of the Antarctic Peninsula, for example, broke into thousands of small icebergs, which subsequently floated away as a result of the formation of more than 2,000 meltwater lakes on its surface over the prior decade. Our research project addresses the reasons why surface lakes form on Antarctic ice shelves and how these surface lakes subsequently contribute to the forces that may contribute to ice-shelf breakup like that of the Larsen B. Our project focuses primarily on making precise global positioning system (GPS) measurements of ice-shelf bending in response to the filling and draining of a surface lake on the McMurdo Ice Shelf. The observed vertical displacements (on the order of tens of centimeters) in response to lake filling will be used to calibrate and test computer simulation models that predict the response of ice shelves to surface lakes more generally and in a variety of future climate conditions. Our project will make hourly measurements of both vertical ice-shelf movements (using GPS surveying instruments) and of temperature and sunlight conditions (that drive melting) around a surface lake located close to the McMurdo Station airfield. Following this initial data-gathering effort, computer simulations and other more theoretical analysis will be undertaken to determine the suitability of the chosen McMurdo Ice Shelf surface lake as a field-laboratory for continued study. Ultimately, the research will contribute to understanding of the glaciological processes that link climate change to rising sea level. A successful outcome of the research will allow glaciologists to better assess the processes that promote or erode the influence Antarctic ice shelves have in controlling the transfer of ice from the interior of Antarctica into the ocean. The project will undertake two outreach activities: (1) web-posting of a field-activity journal and (2) establishing an open-access glaciological teaching and outreach web-sharing site for the International Glaciological Society. The proposed project seeks to experimentally verify a theory of ice-shelf instability proposed to explain the explosive break-up of Larsen B Ice Shelf in 2002. This theory holds that the filling and draining of supraglacial lakes on floating ice shelves induces sufficient flexure stress within the ice to (a) induce upward/downward propagating fractures originating at the base/surface of the ice shelf that (b) dissect the ice shelf into fragments that tend to have widths less than about half the ice thickness. The significance of narrow widths is that they promote capsize of the ice-shelf fragments during the break-up process. This capsize releases large amounts of gravitational potential energy (comparable to thousands of kilotons of TNT for the Larsen B Ice Shelf) thereby promoting explosiveness of the Larsen B event. The observational motivation for experimentally verifying the surface-lake mechanism for ice-shelf breakup is based on the fact that \u003e2,000 surface lakes developed on the Larsen B Ice Shelf in the decade prior to its break up, and that these lakes were observed (via satellite imagery) to drain in a coordinated fashion during the day prior to the initiation of the break up. The field-observation component of the project will focus on a supraglacial lake on the McMurdo Ice Shelf where there is persistent summer season surface melting. The lake will be studied during a single provisional field season to determine whether grooming of surrounding surface streams and shorelines with heavy construction equipment will allow surface water to be manually encouraged to fill the lake. If successfully encouraged to develop, the McMurdo Ice Shelf surface lake will allow measurements of key ice-shelf flexure and stress variables needed to develop the theory of ice-shelf surface lakes without having to access the much more logistically demanding surface lakes of ice-shelves located elsewhere in Antarctica. Data to be gathered during the 6-week provisional field season include: energy- and water-balance parameters determining how the surface lake grows and fills, and various global positioning system measurements of the vertical bending of the ice sheet in response to the changing meltwater load contained within the surface lake. These data will be used to (1) constrain a computer model of viscoelastic flexure and possible fracture of the ice shelf in response to the increasing load of meltwater in the lake, and (2) determine whether continued study of the incipient surface-meltwater lake features on the McMurdo Ice Shelf provides a promising avenue for constraining the more-general behavior of surface meltwater lakes on other ice shelves located in warmer parts of Antarctica. Computer models constrained by the observational data obtained from the field project will inform energy- and water-balance models of ice shelves in general, and allow more accurate forecasts of changing ice-shelf conditions surrounding the inland ice of Antarctica. The project will create the first-ever ground-based observations useful for spawning the development of models capable of predicting viscoelastic and fracture behavior of ice shelves in response to supraglacial lake evolution, including slow changes due to energy balance effects, as well as fast changes due to filling and draining.", "east": 166.5057, "geometry": "POINT(166.3344 -77.91835)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e AWS", "is_usap_dc": true, "keywords": "USAP-DC; AWOS", "locations": null, "north": -77.9007, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "MacAyeal, Douglas", "platforms": "LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e AWOS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.936, "title": "Impact of Supraglacial Lakes on Ice-Shelf Stability", "uid": "p0000138", "west": 166.1631}, {"awards": "1143981 Domack, Eugene", "bounds_geometry": "POLYGON((-69.9517 -52.7581,-69.02971 -52.7581,-68.10772 -52.7581,-67.18573 -52.7581,-66.26374 -52.7581,-65.34175 -52.7581,-64.41976 -52.7581,-63.49777 -52.7581,-62.57578 -52.7581,-61.65379 -52.7581,-60.7318 -52.7581,-60.7318 -54.31551,-60.7318 -55.87292,-60.7318 -57.43033,-60.7318 -58.98774,-60.7318 -60.54515,-60.7318 -62.10256,-60.7318 -63.65997,-60.7318 -65.21738,-60.7318 -66.77479,-60.7318 -68.3322,-61.65379 -68.3322,-62.57578 -68.3322,-63.49777 -68.3322,-64.41976 -68.3322,-65.34175 -68.3322,-66.26374 -68.3322,-67.18573 -68.3322,-68.10772 -68.3322,-69.02971 -68.3322,-69.9517 -68.3322,-69.9517 -66.77479,-69.9517 -65.21738,-69.9517 -63.65997,-69.9517 -62.10256,-69.9517 -60.54515,-69.9517 -58.98774,-69.9517 -57.43033,-69.9517 -55.87292,-69.9517 -54.31551,-69.9517 -52.7581))", "dataset_titles": "Expedition Data; Processed Camera Images acquired during the Laurence M. Gould expedition LMG1311", "datasets": [{"dataset_uid": "001366", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG1702"}, {"dataset_uid": "601311", "doi": "10.15784/601311", "keywords": "Antarctica; Antarctic Peninsula; Benthic Images; Camera; LARISSA; LMG1311; Marine Geoscience; Photo; Photo/video; Photo/Video; R/v Laurence M. Gould", "people": "Domack, Eugene Walter", "repository": "USAP-DC", "science_program": "LARISSA", "title": "Processed Camera Images acquired during the Laurence M. Gould expedition LMG1311", "url": "https://www.usap-dc.org/view/dataset/601311"}, {"dataset_uid": "000402", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG1702"}], "date_created": "Fri, 29 Dec 2017 00:00:00 GMT", "description": "This project aims to identify which portions of the glacial cover in the Antarctic Peninsula are losing mass to the ocean. This is an important issue to resolve because the Antarctic Peninsula is warming at a faster rate than any other region across the earth. Even though glaciers across the Antarctic Peninsula are small, compared to the continental ice sheet, defining how rapidly they respond to both ocean and atmospheric temperature rise is critical. It is critical because it informs us about the exact mechanisms which regulate ice flow and melting into the ocean. For instance, after the break- up of the Larsen Ice Shelf in 2002 many glaciers began to flow rapidly into the sea. Measuring how much ice was involved is difficult and depends upon accurate estimates of volume and area. One way to increase the accuracy of our estimates is to measure how fast the Earth\u0027s crust is rebounding or bouncing back, after the ice has been removed. This rebound effect can be measured with very precise techniques using instruments locked into ice free bedrock surrounding the area of interest. These instruments are monitored by a set of positioning satellites (the Global Positioning System or GPS) in a continuous fashion. Of course the movement of the Earth\u0027s bedrock relates not only to the immediate response but also the longer term rate that reflects the long vanished ice masses that once covered the entire Antarctic Peninsula?at the time of the last glaciation. These rebound measurements can, therefore, also tell us about the amount of ice which covered the Antarctic Peninsula thousands of years ago. Glacial isostatic rebound is one of the complicating factors in allowing us to understand how much the larger ice sheets are losing today, something that can be estimated by satellite techniques but only within large errors when the isostatic (rebound) correction is unknown. The research proposed consists of maintaining a set of six rebound stations until the year 2016, allowing for a longer time series and thus more accurate estimates of immediate elastic and longer term rebound effects. It also involves the establishment of two additional GPS stations that will focus on constraining the \"bull\u0027s eye\" of rebound suggested by measurements over the past two years. In addition, several more geologic data points will be collected that will help to reconstruct the position of the ice sheet margin during its recession from the full ice sheet of the last glacial maximum. These will be based upon the coring of marine sediment sequences now recognized to have been deposited along the margins of retreating ice sheets and outlets. Precise dating of the ice margin along with the new and improved rebound data will help to constrain past ice sheet configurations and refine geophysical models related to the nature of post glacial rebound. Data management will be under the auspices of the UNAVCO polar geophysical network or POLENET and will be publically available at the time of station installation. This project is a small scale extension of the ongoing LARsen Ice Shelf, Antarctica Project (LARISSA), an IPY (International Polar Year)-funded interdisciplinary study aimed at understanding earth system connections related to the Larsen Ice Shelf and the northern Antarctic Peninsula.", "east": -60.7318, "geometry": "POINT(-65.34175 -60.54515)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e CAMERAS \u003e CAMERAS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e SEISMIC REFLECTION PROFILERS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD; IN SITU/LABORATORY INSTRUMENTS \u003e CHEMICAL METERS/ANALYZERS \u003e FLUOROMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e AWS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e ECHO SOUNDERS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e THERMOSALINOGRAPHS", "is_usap_dc": false, "keywords": "LMG1702; R/V LMG", "locations": null, "north": -52.7581, "nsf_funding_programs": "Antarctic Integrated System Science", "paleo_time": null, "persons": "Kohut, Josh; Domack, Eugene Walter", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG", "repo": "R2R", "repositories": "R2R; USAP-DC", "science_programs": null, "south": -68.3322, "title": "Continuation of the LARISSA Continuous GPS Network in View of Observed Dynamic Response to Antarctic Peninsula Ice Mass Balance and Required Geologic Constraints", "uid": "p0000233", "west": -69.9517}, {"awards": "0632136 Nyblade, Andrew; 0632322 Wilson, Terry", "bounds_geometry": "POLYGON((-20 -70,-1 -70,18 -70,37 -70,56 -70,75 -70,94 -70,113 -70,132 -70,151 -70,170 -70,170 -72,170 -74,170 -76,170 -78,170 -80,170 -82,170 -84,170 -86,170 -88,170 -90,151 -90,132 -90,113 -90,94 -90,75 -90,56 -90,37 -90,18 -90,-1 -90,-20 -90,-20 -88,-20 -86,-20 -84,-20 -82,-20 -80,-20 -78,-20 -76,-20 -74,-20 -72,-20 -70))", "dataset_titles": "Incorporated Research Institutions for Seismology (IRIS); University NAVSTAR Consortium (UNAVCO)", "datasets": [{"dataset_uid": "000132", "doi": "", "keywords": null, "people": null, "repository": "IRIS", "science_program": null, "title": "Incorporated Research Institutions for Seismology (IRIS)", "url": "http://www.iris.edu/mda/YT?timewindow=2007-2018"}, {"dataset_uid": "000131", "doi": "", "keywords": null, "people": null, "repository": "UNAVCO", "science_program": null, "title": "University NAVSTAR Consortium (UNAVCO)", "url": "http://www.unavco.org/data/gps-gnss/data-access-methods/dai2/app/dai2.html#groupingMod=contains;grouping=POLENET%20-%20ANET;scope=Station;sampleRate=normal"}], "date_created": "Thu, 22 Jan 2015 00:00:00 GMT", "description": "This project constructs POLENET a network of GPS and seismic stations in West Antarctica to understand how the mass of the West Antarctic ice sheet (WAIS) changes with time. The information is ultimately used to predict sea level rise accompanying global warming and interpret climate change records. The GPS (global positioning system) stations measure vertical and horizontal movements of bedrock, while the seismic stations characterize physical properties of the ice/rock interface, lithosphere, and mantle. Combined with satellite data, this project offers a more complete picture of the ice sheet\u0027s current state, its likely change in the near future, and its overall size during the last glacial maximum. This data will also be used to infer sub-ice sheet geology and the terrestrial heat flux, critical inputs to models of glacier movement. As well, this project improves tomographic models of the earth\u0027s deep interior and core through its location in the Earth\u0027s poorly instrumented southern hemisphere. \u003cbr/\u003e\u003cbr/\u003e\u003cbr/\u003e\u003cbr/\u003eBroader impacts of this project are varied. The work is relevant to society for improving our understanding of the impacts of global warming on sea level rise. It also supports education at the postdoctoral, graduate, and undergraduate levels, and outreach to groups underrepresented in the sciences. As an International Polar Year contribution, this project establishes a legacy of infrastructure for polar measurements. It also involves an international collaboration of twenty four countries. For more information see IPY Project #185 at IPY.org. NSF is supporting a complementary Arctic POLENET array being constructed in Greenland under NSF Award #0632320.", "east": 170.0, "geometry": "POINT(75 -80)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS", "is_usap_dc": true, "keywords": "Antarctica; Bedrock; Ice/Rock Interface; Climate Change; Seismic; West Antarctic Ice Sheet; FIELD SURVEYS; LABORATORY; Not provided; FIELD INVESTIGATION; Mass Balance; COMPUTERS; Sub-Ice Sheet Geology; Sea Level; Terrestrial Heat Flux", "locations": "Antarctica; West Antarctic Ice Sheet", "north": -70.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Wilson, Terry; Bevis, Michael; Anandakrishnan, Sridhar; Wiens, Douglas; Aster, Richard; Smalley, Robert; Nyblade, Andrew; Winberry, Paul; Hothem, Larry; Dalziel, Ian W.; Huerta, Audrey D.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided; OTHER \u003e MODELS \u003e COMPUTERS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "IRIS", "repositories": "IRIS; UNAVCO", "science_programs": null, "south": -90.0, "title": "Collaborative Research: IPY: POLENET-Antarctica: Investigating Links Between Geodynamics and Ice Sheets", "uid": "p0000315", "west": -20.0}, {"awards": "0732946 Steffen, Konrad", "bounds_geometry": null, "dataset_titles": "Larsen C automatic weather station data 2008\u20132011; Mean surface mass balance over Larsen C ice shelf, Antarctica (1979-2014), assimilated to in situ GPR and snow height data", "datasets": [{"dataset_uid": "601056", "doi": "10.15784/601056", "keywords": "Antarctica; Antarctic Peninsula; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Larsen C Ice Shelf; Radar", "people": "McGrath, Daniel; Kuipers Munneke, Peter; Steffen, Konrad", "repository": "USAP-DC", "science_program": null, "title": "Mean surface mass balance over Larsen C ice shelf, Antarctica (1979-2014), assimilated to in situ GPR and snow height data", "url": "https://www.usap-dc.org/view/dataset/601056"}, {"dataset_uid": "601445", "doi": "10.15784/601445", "keywords": "Antarctica; Atmosphere; AWS; Foehn Winds; Ice Shelf; Larsen C Ice Shelf; Larsen Ice Shelf; Meteorology; Weather Station Data", "people": "Bayou, Nicolas; Steffen, Konrad; McGrath, Daniel", "repository": "USAP-DC", "science_program": null, "title": "Larsen C automatic weather station data 2008\u20132011", "url": "https://www.usap-dc.org/view/dataset/601445"}], "date_created": "Wed, 03 Oct 2012 00:00:00 GMT", "description": "This award supports a field experiment, with partners from Chile and the Netherlands, to determine the state of health and stability of Larsen C ice shelf in response to climate change. Significant glaciological and ecological changes are taking place in the Antarctic Peninsula in response to climate warming that is proceeding at 6 times the global average rate. Following the collapse of Larsen A ice shelf in 1995 and Larsen B in 2002, the outlet glaciers that nourished them with land ice accelerated massively, losing a disproportionate amount of ice to the ocean. Further south, the much larger Larsen C ice shelf is thinning and measurements collected over more than a decade suggest that it is doomed to break up. The intellectual merit of the project will be to contribute to the scientific knowledge of one of the Antarctic sectors where the most significant changes are taking place at present. The project is central to a cluster of International Polar Year activities in the Antarctic Peninsula. It will yield a legacy of international collaboration, instrument networking, education of young scientists, reference data and scientific analysis in a remote but globally relevant glaciological setting. The broader impacts of the project will be to address the contribution to sea level rise from Antarctica and to bring live monitoring of climate and ice dynamics in Antarctica to scientists, students, the non-specialized public, the press and the media via live web broadcasting of progress, data collection, visualization and analysis. Existing data will be combined with new measurements to assess what physical processes are controlling the weakening of the ice shelf, whether a break up is likely, and provide baseline data to quantify the consequences of a breakup. Field activities will include measurements using the Global Positioning System (GPS), installation of automatic weather stations (AWS), ground penetrating radar (GPR) measurements, collection of shallow firn cores and temperature measurements. These data will be used to characterize the dynamic response of the ice shelf to a variety of phenomena (oceanic tides, iceberg calving, ice-front retreat and rifting, time series of weather conditions, structural characteristics of the ice shelf and bottom melting regime, and the ability of firn to collect melt water and subsequently form water ponds that over-deepen and weaken the ice shelf). This effort will complement an analysis of remote sensing data, ice-shelf numerical models and control methods funded independently to provide a more comprehensive analysis of the ice shelf evolution in a changing climate.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e AWS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e TEMPERATURE PROFILERS", "is_usap_dc": false, "keywords": "Climate Warming; Firn; COMPUTERS; Ice Dynamic; USAP-DC; Glaciological; Thinning; Sea Level Rise; FIELD SURVEYS; FIELD INVESTIGATION; USA/NSF; AMD; Ice Edge Retreat; LABORATORY; Climate Change; Antarctic Peninsula; Amd/Us; Melting", "locations": "Antarctic Peninsula", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Steffen, Konrad", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; OTHER \u003e MODELS \u003e COMPUTERS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "IPY: Stability of Larsen C Ice Shelf in a Warming Climate", "uid": "p0000087", "west": null}, {"awards": "0440847 Raymond, Charles", "bounds_geometry": null, "dataset_titles": "GPS-Measured Ice Velocities and Strain Data from the Ross and Amundsen Sea Ice Flow Divide, West Antarctica; Polarimetric Radar Data from the Ross and Amundsen Sea Ice Flow Divide, West Antarctica", "datasets": [{"dataset_uid": "609503", "doi": "10.7265/N5222RQ8", "keywords": "Antarctica; Geology/Geophysics - Other; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPS; Ice Flow Velocity; Ross-Amundsen Divide; Strain", "people": "Matsuoka, Kenichi; Power, Donovan; Rasmussen, Al", "repository": "USAP-DC", "science_program": null, "title": "GPS-Measured Ice Velocities and Strain Data from the Ross and Amundsen Sea Ice Flow Divide, West Antarctica", "url": "https://www.usap-dc.org/view/dataset/609503"}, {"dataset_uid": "609496", "doi": "10.7265/N5TH8JNG", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Radar; Ross-Amundsen Divide", "people": "Power, Donovan; Fujita, Shuji; Raymond, Charles; Matsuoka, Kenichi", "repository": "USAP-DC", "science_program": null, "title": "Polarimetric Radar Data from the Ross and Amundsen Sea Ice Flow Divide, West Antarctica", "url": "https://www.usap-dc.org/view/dataset/609496"}], "date_created": "Mon, 29 Aug 2011 00:00:00 GMT", "description": "This award supports a project to investigate fabrics with ground-based radar measurements near the Ross/Amundsen Sea ice-flow divide where a deep ice core will be drilled. The alignment of crystals in ice (crystal-orientation fabric) has an important effect on ice deformation. As ice deforms, anisotropic fabrics are produced, which, in turn, influence further deformation. Measurement of ice fabric variations can help reveal the deformation history of the ice and indicate how the ice will deform in the future. Ice cores provide opportunities to determine a vertical fabric profile, but horizontal variations of fabrics remain unknown. Remote sensing with ice-penetrating radar is the only way to do that over large areas. Preliminary results show that well-established polarimetric methods can detect the degree of horizontal anisotropy of fabrics and their orientation, even when they are nearly vertical-symmetric fabrics. In conjunction with ice deformation history, our first mapping of ice fabrics will contribute to modeling ice flow near the future ice core site. The project will train a graduate student and provide research experiences for two under graduate students both in field and laboratory. The project will contribute to ongoing West Antarctic ice sheet program efforts to better understand the impact of the ice sheet on global sea level rise. This project also supports an international collaboration between US and Japanese scientists.", "east": null, "geometry": null, "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e RADAR; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS", "is_usap_dc": true, "keywords": "GPS; FIELD SURVEYS; Antarctic; Radar; Antarctica; FIELD INVESTIGATION; Ice Sheet; Not provided; Ross-Amundsen Divide; West Antarctica; West Antarctic Ice Sheet", "locations": "Antarctica; Ross-Amundsen Divide; West Antarctica; Antarctic; West Antarctic Ice Sheet", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Matsuoka, Kenichi; Power, Donovan; Fujita, Shuji; Raymond, Charles; Rasmussen, Al", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Detection of Crystal Orientation Fabrics near the Ross/Amundsen Sea Ice-flow Divide and at the Siple Dome Ice Core Site using Polarimetric Radar Methods", "uid": "p0000024", "west": null}, {"awards": "0538120 Catania, Ginny; 0538015 Hulbe, Christina", "bounds_geometry": "POLYGON((154.71 -82.78,154.79000000000002 -82.78,154.87 -82.78,154.95 -82.78,155.03 -82.78,155.11 -82.78,155.19 -82.78,155.26999999999998 -82.78,155.35 -82.78,155.43 -82.78,155.51 -82.78,155.51 -82.788,155.51 -82.796,155.51 -82.804,155.51 -82.812,155.51 -82.82,155.51 -82.828,155.51 -82.836,155.51 -82.844,155.51 -82.852,155.51 -82.86,155.43 -82.86,155.35 -82.86,155.26999999999998 -82.86,155.19 -82.86,155.11 -82.86,155.03 -82.86,154.95 -82.86,154.87 -82.86,154.79000000000002 -82.86,154.71 -82.86,154.71 -82.852,154.71 -82.844,154.71 -82.836,154.71 -82.828,154.71 -82.82,154.71 -82.812,154.71 -82.804,154.71 -82.796,154.71 -82.788,154.71 -82.78))", "dataset_titles": "Grounding Line Strain Grid Surveys, Kamb Ice Stream, Antarctica; Ice-Penetrating Radar Data Across Siple Coast Grounding Lines", "datasets": [{"dataset_uid": "609474", "doi": "10.7265/N5M043BH", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; GPR; Grounding Line; Radar; Siple Coast", "people": "Catania, Ginny; Hulbe, Christina", "repository": "USAP-DC", "science_program": null, "title": "Ice-Penetrating Radar Data Across Siple Coast Grounding Lines", "url": "https://www.usap-dc.org/view/dataset/609474"}, {"dataset_uid": "609494", "doi": "10.7265/N5Z899C6", "keywords": "Antarctica; Geodesy; Geology/Geophysics - Other; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPS; Grounding Line; Kamb Ice Stream; Strain", "people": "Hulbe, Christina", "repository": "USAP-DC", "science_program": null, "title": "Grounding Line Strain Grid Surveys, Kamb Ice Stream, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609494"}], "date_created": "Sat, 02 Jul 2011 00:00:00 GMT", "description": "0538120\u003cbr/\u003eCatania\u003cbr/\u003eThis award supports a project to identify and map ice surface and internal features that chronicle the sequence of events leading to the shut-down of Kamb ice stream. In particular, the project will study past grounding line migration and the relationship between that process and ice stream shutdown. The intellectual merits of the project include the fact that an understanding of such processes has important implications for our ability to accurately predict mass balance changes in this region. Currently, one of the five major West Antarctic ice streams, Kamb, is quiescent, and another, Whillans, is slowing in its downstream reaches. The Kamb shutdown appears to have begun at its downstream end but beyond that simple observation, it is not possible, yet, to draw meaningful comparisons between the two adjacent streams. We do not know if current events on Whillans Ice Stream are similar to what transpired during the Kamb shut-down. The work proposed here intends to bridge that gap. It is expected that this effort will yield useful insights into the influence of grounding line dynamics on ice stream flow. The work will involve a combination of field investigations using radio-echo sounding and GPS combined with computational efforts involving the interpretation of ice-surface features such as relict flow traces and crevasses. The broader impacts of the project will be in addressing a global environmental problem with critical societal implications, training the next generation of scientists and engineers to serve the nation, and encouraging women to pursue scientific or engineering careers. Participants from both institutions are involved in a range of public outreach activities.", "east": 155.51, "geometry": "POINT(155.11 -82.82)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e RADAR", "is_usap_dc": true, "keywords": "Not provided; Ice Sheet Elevation; West Antarctic Ice Stream; MODELS; Ice Sheet Thickness; West Antarctic Ice Sheet; Kamb Ice Stream; Antarctic Ice Sheet; Ice Sheet; Ice Stream Motion; Antarctica; Siple Dome; Grounding Line; FIELD INVESTIGATION; GPS; FIELD SURVEYS; West Antarctica; Ice Stream; Radar", "locations": "Antarctica; Kamb Ice Stream; West Antarctic Ice Stream; Antarctic Ice Sheet; West Antarctica; West Antarctic Ice Sheet; Siple Dome", "north": -82.78, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Hulbe, Christina; Catania, Ginny", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided; OTHER \u003e MODELS \u003e MODELS; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -82.86, "title": "Collaborative Research: Grounding Line Forensics: The History of Grounding Line Retreat in the Kamb Ice Stream Outlet Region", "uid": "p0000019", "west": 154.71}, {"awards": "0337567 Jacobel, Robert", "bounds_geometry": "POLYGON((130 -78,133 -78,136 -78,139 -78,142 -78,145 -78,148 -78,151 -78,154 -78,157 -78,160 -78,160 -79.2,160 -80.4,160 -81.6,160 -82.8,160 -84,160 -85.2,160 -86.4,160 -87.6,160 -88.8,160 -90,157 -90,154 -90,151 -90,148 -90,145 -90,142 -90,139 -90,136 -90,133 -90,130 -90,130 -88.8,130 -87.6,130 -86.4,130 -85.2,130 -84,130 -82.8,130 -81.6,130 -80.4,130 -79.2,130 -78))", "dataset_titles": "Glaciological Investigations of the Bulge and Trunk of Kamb Ice Stream, West Antarctica; Radar Studies of Internal Stratigraphy and Bed Topography along the US ITASE-II Traverse", "datasets": [{"dataset_uid": "609380", "doi": "10.7265/N5ZC80SH", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Kamb Ice Stream", "people": "Jacobel, Robert", "repository": "USAP-DC", "science_program": null, "title": "Glaciological Investigations of the Bulge and Trunk of Kamb Ice Stream, West Antarctica", "url": "https://www.usap-dc.org/view/dataset/609380"}, {"dataset_uid": "609475", "doi": "10.7265/N5G73BMS", "keywords": "Antarctica; Elevation; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Thickness; ITASE; South Pole; Taylor Dome", "people": "Jacobel, Robert", "repository": "USAP-DC", "science_program": "ITASE", "title": "Radar Studies of Internal Stratigraphy and Bed Topography along the US ITASE-II Traverse", "url": "https://www.usap-dc.org/view/dataset/609475"}], "date_created": "Wed, 20 Oct 2010 00:00:00 GMT", "description": "This award supports a project to test whether Kamb Ice Stream (formerly Ice Stream C (ISC)), an ice stream\u003cbr/\u003ethat is thought to have stopped ~150 years ago, may be already in the process of restarting. If yes, it will help establish what is the rate of ice stream reactivation and what mechanisms are controlling this rate. If there is no evidence for ongoing ice stream reactivation, the physical controls that are preventing it will be examined and alternative scenarios for near-future evolution of this ice stream will be explored. One such scenario is an increase in ice diversion toward the neighboring Whillans Ice Stream. Such diversion may help prevent a complete stoppage of Whillans Ice Stream,which has been slowing down for at least the last 24 years. This project will consist of two components: (1) field observations of bed properties,geometry of internal radar reflectors, as well as surface strain rates and velocity/topography changes using Ice-Penetrating Radar and differential Global Positioning System, (2) numerical modeling study of near future(~100-1000 years) evolution of Kamb Ice Stream. The field component will be focused on the bulge-to-trunk transition, which is located at the present time just downstream of the so-called camp UpC. Reactivation of Kamb Ice Stream should be reflected in a downstream migration of the bulge-trunk transition at possibly high rates (bulge migration rates of ~km/yr occur on surging mountain glaciers). The modeling\u003cbr/\u003ecomponent will be used to generate predictions regarding the near-future behavior of Kamb Ice Stream. This project will provide training opportunities for at least two undergraduate students (per year) at St. Olaf College and for one\u003cbr/\u003eundergraduate student (per year) at UCSC. This collaboration will bring together scientists from three different types of US institutions: (1) a liberal arts college (St.Olaf College), (2) a public research university (UCSC) and (3) a NASA research laboratory (JPL). The project will also help build a new glaciological research program at UCSC. Project results will be incorporated into undergraduate and graduate courses at UCSC and will be made available\u003cbr/\u003eto the general public and educators through downloadable graphics and animations posted on the research website of the UCSC PI. Field data resulting from the project will be posted in the Antarctic Glaciological Data Center for use by other investigators.", "east": 160.0, "geometry": "POINT(145 -84)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e RADAR ECHO SOUNDERS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e RADAR", "is_usap_dc": true, "keywords": "Ice; Antarctic Glaciations; Radar; Antarctic Ice Sheet; Radar Echo Sounder; Ice Sheet Thickness; Ice Stream; Ice Sheet Elevation; Not provided; Radar Echo Sounding; Ice Stratigraphy; Antarctica; West Antarctic Ice Sheet; Continental Ice Sheet; Ice Cap; Antarctic; US ITASE; FIELD SURVEYS; Ice Thickness; FIELD INVESTIGATION", "locations": "Antarctic; Antarctica; Antarctic Ice Sheet; West Antarctic Ice Sheet", "north": -78.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Jacobel, Robert", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "ITASE", "south": -90.0, "title": "Collaborative Research: Is Ice Stream C Restarting? Glaciological Investigations of the \u0027Bulge\u0027 and the Trunk of Ice Stream C, West Antartica", "uid": "p0000192", "west": 130.0}, {"awards": "0003619 Dalziel, Ian", "bounds_geometry": null, "dataset_titles": "Expedition Data; Expedition data of LMG9810", "datasets": [{"dataset_uid": "002092", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG9810"}, {"dataset_uid": "002678", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG9810", "url": "https://www.rvdata.us/search/cruise/LMG9810"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a collaborative research program to initiate a Global Positioning System (GPS) network to measure crustal motions in the bedrock surrounding and underlying the West Antarctic Ice Sheet (WAIS). Evaluation of the role of both tectonic and ice-induced crustal motions of the WAIS bedrock is a critical goal for understanding past, present, and future dynamics of WAIS and its potential role in future global change scenarios, as well as improving our understanding of the role of Antarctica in global plate motions. The extent of active tectonism in West Antarctica is largely speculative, as few data exist that constrain its geographic distribution, directions, or rates of deformation. Active tectonism and the influence of bedrock on the WAIS have been highlighted recently by geophysical data indicating active subglacial volcanism and control of ice streaming by the presence of sedimentary basins. The influence of bedrock crustal motion on the WAIS and its future dynamics is a fundamental issue. Existing GPS projects are located only on the fringe of the ice sheet and do not address the regional picture. It is important that baseline GPS measurements on the bedrock around and within the WAIS be started so that a basis is established for detecting change.\u003cbr/\u003e\u003cbr/\u003eTo measure crustal motions, this project will build a West Antarctica GPS Network (WAGN) of at least 15 GPS sites across the interior of West Antarctica (approximately the size of the contiguous United States from the Rocky Mountains to the Pacific coast) over a two-year period beginning in the Antarctic field season 2001-2002. The planned network is designed using the Multi-modal Occupation Strategy (MOST), in which a small number of independent GPS \"roving\" receivers make differential measurements against a network of continuous GPS stations for comparatively short periods at each site. This experimental strategy, successfully implemented by a number of projects in California, S America, the SW Pacific and Central Asia, minimizes logistical requirements, an essential element of application of GPS geodesy in the scattered and remote outcrops of the WAIS bedrock.\u003cbr/\u003e\u003cbr/\u003eThe WAGN program will be integrated with the GPS network that has been established linking the Antarctic Peninsula with South America through the Scotia arc (Scotia Arc GPS Project (SCARP)). It will also interface with stations currently measuring motion across the Ross Embayment, and with the continent-wide GIANT program of the Working Group on Geodesy and Geographic Information Systems of the Scientific Committee on Antarctic Research (SCAR). The GPS network will be based on permanent monuments set in solid rock outcrops that will have near-zero set-up error for roving GPS occupations, and that can be directly converted to a continuous GPS site when future technology makes autonomous operation and satellite data linkage throughout West Antarctica both reliable and economical. The planned network both depends on and complements the existing and planned continuous networks. It is presently not practical, for reasons of cost and logistics, to accomplish the measurements proposed herein with either a network of continuous stations or traditional campaigns.\u003cbr/\u003e\u003cbr/\u003eThe proposed WAGN will complement existing GPS projects by filling a major gap in coverage among several discrete crustal blocks that make up West Antarctica, a critical area of potential bedrock movements. If crustal motions are relatively slow, meaningful results will only begin to emerge within the five-year maximum period of time for an individual funded project. Hence this proposal is only to initiate the network and test precision and velocities at the most critical sites. Once built, however, the network will yield increasingly meaningful results with the passage of time. Indeed, the slower the rates turn out to be, the more important an early start to measuring. It is anticipated that the results of this project will initiate an iterative process that will gradually resolve into an understanding of the contributions from plate rotations and viscoelastic and elastic motions resulting from deglaciation and ice mass changes. Velocities obtained from initial reoccupation of the most critical sites will dictate the timing of a follow-up proposal for reoccupation of the entire network when detectable motions have occurred.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "R/V LMG", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Dalziel, Ian W.", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "Collaborative Research: A GPS Network to Determine Crustal Motions in the Bedrock of the West Antarctic Ice Sheet: Phase I - Installation", "uid": "p0000859", "west": null}, {"awards": "0440666 Waddington, Edwin", "bounds_geometry": null, "dataset_titles": "Histories of Accumulation, Thickness, and WAIS Divide Location, Antarctica", "datasets": [{"dataset_uid": "609473", "doi": "10.7265/N5QR4V2J", "keywords": "Antarctica; Elevation; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; WAIS Divide; WAIS Divide Ice Core", "people": "Koutnik, Michelle; Waddington, Edwin D.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Histories of Accumulation, Thickness, and WAIS Divide Location, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609473"}], "date_created": "Thu, 04 Mar 2010 00:00:00 GMT", "description": "This award supports development of a new modeling approach that will extract information about past snow accumulation rate in both space and time in the vicinity of the future ice core near the Ross-Amundsen divide of the West Antarctic Ice Sheet (WAIS). Internal layers, detected by ice-penetrating radar, are isochrones, or former ice-sheet surfaces that have been buried by subsequent snowfall, and distorted by ice flow. Extensive ice-penetrating radar data are available over the inland portion of the WAIS. Layers have been dated back to 17,000 years before present. The radar data add the spatial dimension to the temporally resolved accumulation record from ice cores. Accumulation rates are traditionally derived from the depths of young, shallow layers, corrected for strain using a local 1-D ice-flow model. Older, deeper layers have been more affected by flow over large horizontal distances. However, it is these deeper layers that contain information on longer-term climate patterns. This project will use geophysical inverse theory and a 2.5D flow-band ice-flow forward model comprising ice-surface and layer-evolution modules, to extract robust transient accumulation patterns by assimilating multiple deeper, more-deformed layers that have previously been intractable. Histories of divide migration, geothermal flux, and surface evolution will also be produced. The grant will support the PhD research of a female graduate student who is a mentor to female socio-economically disadvantaged high-school students interested in science, through the University of Washington Women\u0027s Center. It will also provide a research\u003cbr/\u003eexperience for an undergraduate student, and contribute to a freshman seminar on Scientific Research.", "east": null, "geometry": null, "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS", "is_usap_dc": true, "keywords": "Ross-Amundsen Divide; FIELD SURVEYS; Internal Layers; Ice Flow Model; West Antarctic Ice Sheet; Accumulation; Glacier; Ice Penetrating Radar; Model; MODELS; Snow Accumulation; GPS; Antarctica; Isochron; Not provided; Snowfall; Radar", "locations": "West Antarctic Ice Sheet; Antarctica; Ross-Amundsen Divide", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Koutnik, Michelle; Waddington, Edwin D.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided; OTHER \u003e MODELS \u003e MODELS; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": null, "title": "Histories of accumulation, thickness and WAIS Divide location from radar layers using a new inverse approach", "uid": "p0000018", "west": null}, {"awards": "0230285 Wilson, Terry", "bounds_geometry": "POLYGON((152.833 -75.317,154.4897 -75.317,156.1464 -75.317,157.8031 -75.317,159.4598 -75.317,161.1165 -75.317,162.7732 -75.317,164.4299 -75.317,166.0866 -75.317,167.7433 -75.317,169.4 -75.317,169.4 -75.9186,169.4 -76.5202,169.4 -77.1218,169.4 -77.7234,169.4 -78.325,169.4 -78.9266,169.4 -79.5282,169.4 -80.1298,169.4 -80.7314,169.4 -81.333,167.7433 -81.333,166.0866 -81.333,164.4299 -81.333,162.7732 -81.333,161.1165 -81.333,159.4598 -81.333,157.8031 -81.333,156.1464 -81.333,154.4897 -81.333,152.833 -81.333,152.833 -80.7314,152.833 -80.1298,152.833 -79.5282,152.833 -78.9266,152.833 -78.325,152.833 -77.7234,152.833 -77.1218,152.833 -76.5202,152.833 -75.9186,152.833 -75.317))", "dataset_titles": null, "datasets": null, "date_created": "Sat, 12 Dec 2009 00:00:00 GMT", "description": "OPP-0230285/OPP-0230356\u003cbr/\u003ePIs: Wilson, Terry J./Hothem, Larry D.\u003cbr/\u003e\u003cbr/\u003eThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a project to conduct GPS measurements of bedrock crustal motions in an extended Transantarctic Mountains Deformation network (TAMDEF) to document neotectonic displacements due to tectonic deformation within the West Antarctic rift and/or to mass change of the Antarctic ice sheets. Horizontal displacements related to active neotectonic rifting, strike-slip translations, and volcanism will be tightly constrained by monitoring the combined TAMDEF and Italian VLNDEF networks of bedrock GPS stations along the Transantarctic Mountains and on offshore islands in the Ross Sea. Glacio-isostatic adjustments due to deglaciation since the Last Glacial Maximum and to modern mass change of the ice sheets will be modeled from GPS-derived crustal motions together with new information from other programs on the configurations, thicknesses, deglaciation history and modern mass balance of the ice sheets. Tectonic and rheological information from ongoing structural and seismic investigations in the Victoria Land region will also be integrated in the modeling. The integrative and iterative modeling will yield a holistic interpretation of neotectonics and ice sheet history that will help us to discriminate tectonic crustal displacements from viscoelastic/elastic glacio-isostatic motions. These results will provide key information to interpret broad, continental-scale crustal motion patterns detected by sparse, regionally distributed GPS continuous trackers and by spaceborne instruments. This study will contribute to international programs focused on Antarctic neotectonic and global change issues.\u003cbr/\u003e\u003cbr/\u003eStrategies to meet these science objectives include repeat surveys of key sites in the existing TAMDEF network, extension of the array of TAMDEF sites southward about 250 km along the Transantarctic Mountains, linked measurements with the VLNDEF network, and integration of quasi-continuous trackers within the campaign network. By extending the array of bedrock sites southward, these measurements will cross gradients in predicted vertical motion due to viscoelastic rebound. The southward extension will also allow determination of the southern limit of the active Terror Rift and will provide a better baseline for constraints on any ongoing tectonic displacements across the West Antarctic rift system as a whole that might be possible using GPS data collected by the West Antarctic GPS Network. This project will also investigate unique aspects of GPS geodesy in Antarctica to determine how the error spectrum compares to mid-latitude regions and to identify the optimum measurement and data processing schemes for Antarctic conditions. The geodetic research will improve position accuracies within our network and will also yield general recommendations for deformation monitoring networks in polar regions.\u003cbr/\u003e\u003cbr/\u003eAn education and outreach program is planned and will be targeted at non-science-major undergraduate students taking Earth System Science at Ohio State University. The objective will be to illuminate the research process for nonscientists. This effort will educate students on the process of science and inform them about Antarctica and how it relates to global science issues.", "east": 169.4, "geometry": "POINT(161.1165 -78.325)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS", "is_usap_dc": false, "keywords": "GPS", "locations": null, "north": -75.317, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Wilson, Terry", "platforms": "SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repositories": null, "science_programs": null, "south": -81.333, "title": "Collaborative Research: Transantarctic Mountains Deformation Network: GPS Measurements of Neotectonic Motion in the Antarctic Interior", "uid": "p0000574", "west": 152.833}, {"awards": "0228052 Kreutz, Karl", "bounds_geometry": "POLYGON((161.0434 -77.3002,161.241645 -77.3002,161.43989 -77.3002,161.638135 -77.3002,161.83638 -77.3002,162.034625 -77.3002,162.23287 -77.3002,162.431115 -77.3002,162.62936 -77.3002,162.827605 -77.3002,163.02585 -77.3002,163.02585 -77.3784846,163.02585 -77.4567692,163.02585 -77.5350538,163.02585 -77.6133384,163.02585 -77.691623,163.02585 -77.7699076,163.02585 -77.8481922,163.02585 -77.9264768,163.02585 -78.0047614,163.02585 -78.083046,162.827605 -78.083046,162.62936 -78.083046,162.431115 -78.083046,162.23287 -78.083046,162.034625 -78.083046,161.83638 -78.083046,161.638135 -78.083046,161.43989 -78.083046,161.241645 -78.083046,161.0434 -78.083046,161.0434 -78.0047614,161.0434 -77.9264768,161.0434 -77.8481922,161.0434 -77.7699076,161.0434 -77.691623,161.0434 -77.6133384,161.0434 -77.5350538,161.0434 -77.4567692,161.0434 -77.3784846,161.0434 -77.3002))", "dataset_titles": "Late Holocene Climate Variability, Dry Valleys, Antarctica", "datasets": [{"dataset_uid": "609399", "doi": "10.7265/N5FF3Q92", "keywords": "Antarctica; Borehole Temperature; Chemistry:ice; Chemistry:Ice; Dry Valleys; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Isotope; Mass Balance; Paleoclimate; Physical Properties", "people": "Mayewski, Paul A.; Kreutz, Karl", "repository": "USAP-DC", "science_program": null, "title": "Late Holocene Climate Variability, Dry Valleys, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609399"}], "date_created": "Tue, 21 Oct 2008 00:00:00 GMT", "description": "This award supports a project to collect and develop high-resolution ice core records from the Dry Valleys region of Antarctica, and provide interpretations of interannual to decadal-scale climate variability during the last 2000 years (late Holocene). The project will test hypotheses related to ocean/atmosphere teleconnections (e.g., El Nino Southern Oscillation, Antarctic Oscillation) that may be responsible for major late Holocene climate events such as the Little Ice Age in the Southern Hemisphere. Conceptual and quantitative models of these processes in the Dry Valleys during the late Holocene are critical for understanding recent climate changes, and represent the main scientific merit of the project. We plan to collect intermediate-length ice cores (100-200m) at four sites along transects in Taylor Valley and Wright Valley, and analyze each core at high resolution for stable isotopes (d18O, dD), major ions (Na+, Mg2+, Ca2+, K+, NH4+, Cl-, NO3-, SO42-, MSA), and trace elements (Al, Fe, S, Sr, B). A suite of statistical techniques will be applied to the multivariate glaciochemical dataset to identify chemical associations and to calibrate the time-series records with available instrumental data. Broader impacts of the project include: 1) contributions to several ongoing interdisciplinary Antarctic research programs; 2) graduate and undergraduate student involvement in field, laboratory, and data interpretation activities; 3) use of project data and ideas in several UMaine courses and outreach activities; and 4) data dissemination through peer-reviewed publications, UMaine and other paleoclimate data archive websites, and presentations at national and international meetings.", "east": 163.02585, "geometry": "POINT(162.034625 -77.691623)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MC-ICP-MS; IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e AWS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e HUMIDITY SENSORS; IN SITU/LABORATORY INSTRUMENTS \u003e PRESSURE/HEIGHT METERS \u003e PRESSURE SENSORS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e TEMPERATURE SENSORS", "is_usap_dc": true, "keywords": "Holocene; Climate Research; AWS Climate Data; Paleoclimate; Climate Variation; Dry Valleys; Wright Valley; Little Ice Age; Stable Isotopes; Glaciochemical; Ice Core; FIELD INVESTIGATION; Enso; Antarctic Oscillation; Climate; GPS; El Nino-Southern Oscillation; LABORATORY; Not provided; Climate Change; Ice Core Records; Antarctica; Taylor Valley; FIELD SURVEYS; Variability", "locations": "Antarctica; Dry Valleys; Taylor Valley; Wright Valley", "north": -77.3002, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": "PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY \u003e HOLOCENE", "persons": "Kreutz, Karl; Arcone, Steven; Mayewski, Paul A.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.083046, "title": "Dry Valleys Late Holocene Climate Variability", "uid": "p0000155", "west": 161.0434}, {"awards": "0229546 MacAyeal, Douglas", "bounds_geometry": "POINT(-178 -78)", "dataset_titles": "collection of nascent rift images and description of station deployment; Continuous GPS (static) Data from the Ross Ice Shelf, Antarctica; Giant Icebergs of the Ross Sea, in situ Drift and Weather Measurements, Antarctica; Iceberg Firn Temperatures, Antarctica; Iceberg Harmonic Tremor, Seismometer Data, Antarctica; Iceberg Satellite imagery from stations and ice shelves (full data link not provided); Iceberg Tiltmeter Measurements, Antarctica; Ice Shelf Rift Time-Lapse Photography, Antarctica; Incorporated Research Institutions for Seismology; Nascent Iceberg Webcam Images available during the deployment period; Ross Ice Shelf Firn Temperature, Antarctica; The files contain a short header (number of data samples, sample rate, start time, stop time, channel title)The time series data then follow the header above.; This site mirrors the NSIDC website archive.", "datasets": [{"dataset_uid": "609352", "doi": "10.7265/N5M61H55", "keywords": "Glaciology; Iceberg; Oceans; Ross Ice Shelf; Sea Ice; Snow/ice; Snow/Ice; Southern Ocean; Temperature", "people": "MacAyeal, Douglas; Sergienko, Olga; Thom, Jonathan", "repository": "USAP-DC", "science_program": null, "title": "Iceberg Firn Temperatures, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609352"}, {"dataset_uid": "609350", "doi": "10.7265/N5VM496K", "keywords": "AWS; Glaciology; GPS; Iceberg; Meteorology; Oceans; Ross Sea; Sea Ice; Southern Ocean; Weatherstation", "people": "Bassis, Jeremy; Aster, Richard; Okal, Emile; MacAyeal, Douglas", "repository": "USAP-DC", "science_program": null, "title": "Giant Icebergs of the Ross Sea, in situ Drift and Weather Measurements, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609350"}, {"dataset_uid": "609351", "doi": "10.7265/N5QV3JGV", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Photo/video; Photo/Video; Ross Ice Shelf", "people": "Brunt, Kelly; MacAyeal, Douglas", "repository": "USAP-DC", "science_program": null, "title": "Ice Shelf Rift Time-Lapse Photography, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609351"}, {"dataset_uid": "609347", "doi": "10.7265/N57W694M", "keywords": "Antarctica; Geodesy; Geology/Geophysics - Other; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPS; Ross Ice Shelf; Southern Ocean", "people": "Brunt, Kelly; MacAyeal, Douglas; King, Matthew", "repository": "USAP-DC", "science_program": null, "title": "Continuous GPS (static) Data from the Ross Ice Shelf, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609347"}, {"dataset_uid": "001684", "doi": "", "keywords": null, "people": null, "repository": "AMRDC", "science_program": null, "title": "This site mirrors the NSIDC website archive.", "url": "http://uwamrc.ssec.wisc.edu/"}, {"dataset_uid": "609353", "doi": "10.7265/N5GF0RFF", "keywords": "Glaciology; Iceberg; Oceans; Ross Ice Shelf; Sea Ice; Southern Ocean; Tiltmeter", "people": "Kim, Young-Jin; MacAyeal, Douglas; Bliss, Andrew", "repository": "USAP-DC", "science_program": null, "title": "Iceberg Tiltmeter Measurements, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609353"}, {"dataset_uid": "609354", "doi": "10.7265/N5BP00Q3", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ross Ice Shelf; Snow/ice; Snow/Ice; Temperature", "people": "Scambos, Ted; Sergienko, Olga; Muto, Atsu; MacAyeal, Douglas", "repository": "USAP-DC", "science_program": null, "title": "Ross Ice Shelf Firn Temperature, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609354"}, {"dataset_uid": "002568", "doi": "", "keywords": null, "people": null, "repository": "Project website", "science_program": null, "title": "Iceberg Satellite imagery from stations and ice shelves (full data link not provided)", "url": "http://amrc.ssec.wisc.edu/"}, {"dataset_uid": "001598", "doi": "", "keywords": null, "people": null, "repository": "NSIDC", "science_program": null, "title": "The files contain a short header (number of data samples, sample rate, start time, stop time, channel title)The time series data then follow the header above.", "url": "http://nsidc.org"}, {"dataset_uid": "002504", "doi": "", "keywords": null, "people": null, "repository": "Project website", "science_program": null, "title": "Nascent Iceberg Webcam Images available during the deployment period", "url": "https://amrc.ssec.wisc.edu/data/iceberg.html"}, {"dataset_uid": "001639", "doi": "", "keywords": null, "people": null, "repository": "Project website", "science_program": null, "title": "collection of nascent rift images and description of station deployment", "url": "http://thistle.org/nascent/index.shtml"}, {"dataset_uid": "609349", "doi": "10.7265/N5445JD6", "keywords": "Geology/Geophysics - Other; Glaciology; Iceberg; Oceans; Ross Sea; Sea Ice; Seismometer; Southern Ocean", "people": "Bassis, Jeremy; Aster, Richard; Okal, Emile; MacAyeal, Douglas", "repository": "USAP-DC", "science_program": null, "title": "Iceberg Harmonic Tremor, Seismometer Data, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609349"}, {"dataset_uid": "001685", "doi": "", "keywords": null, "people": null, "repository": "IRIS", "science_program": null, "title": "Incorporated Research Institutions for Seismology", "url": "http://www.iris.edu/data/sources.htm"}], "date_created": "Fri, 19 Sep 2008 00:00:00 GMT", "description": "This award supports the study of the drift and break-up of Earth\u0027s largest icebergs, which were recently released into the Ross Sea of Antarctica as a result of calving from the Ross Ice Shelf. The scientific goals of the study are to determine the physics of iceberg motion within the dynamic context of ocean currents, winds, and sea ice, which determine the forces that drive iceberg motion, and the relationship between the iceberg and geographically and topographically determined pinning points on which the iceberg can ground. In addition, the processes by which icebergs influence the local environments (e.g., sea ice conditions near Antarctica, access to penguin rookeries, air-sea heat exchange and upwelling at iceberg margins, nutrient fluxes) will be studied. The processes by which icebergs generate globally far-reaching ocean acoustic signals that are detected within the global seismic (earthquake) sensing networks will also be studied. A featured element of the scientific research activity will be a field effort to deploy automatic weather stations, seismometer arrays and GPS-tracking stations on several of the largest icebergs presently adrift, or about to be adrift, in the Ross Sea. Data generated and relayed via satellite to home institutions in the Midwest will motivate theoretical analysis and computer simulation; and will be archived on an \"iceberg\" website (http://amrc.ssec.wisc.edu/amrc/iceberg.html) for access by scientists and the general public. At the most broad level, the study is justified by the fact that icebergs released by the Antarctic ice sheet represent the largest movements of fresh water within the natural environment (e.g., several of the icebergs to be studied, B15, C19 and others calved since 2000 CE, represent over 6000 cubic kilometers of fresh water-an amount roughly equivalent to 100 years of the flow of the Nile River). A better understanding of the impact of iceberg drift through the environment, and particularly the impact on ocean stratification and mixing, is essential to the understanding of the abrupt global climate changes witnessed by proxy during the ice age and of concern under conditions of future greenhouse warming. On a more specific level, the study will generate a knowledge base useful for the better management of Antarctic logistical resources (e.g., the shipping lanes to McMurdo Station) that can occasionally be influenced by adverse effects icebergs have on sea ice conditions.", "east": -178.0, "geometry": "POINT(-178 -78)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e AWS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e THERMISTORS \u003e THERMISTORS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e HUMIDITY SENSORS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e TEMPERATURE SENSORS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e SEISMOMETERS \u003e SEISMOMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e MMS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e CAMERAS \u003e CAMERAS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e CAMERAS \u003e CAMERAS; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e SEISMOMETERS \u003e SEISMOMETERS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e TEMPERATURE LOGGERS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e TEMPERATURE PROFILERS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e TEMPERATURE SENSORS", "is_usap_dc": true, "keywords": "SEISMOLOGICAL STATIONS; Pressure; AWS; Velocity Measurements; Firn Temperature Measurements; Ice Velocity; Seismology; Ice Sheet Elevation; Harmonic Tremor; Ice Shelf Temperature; Wind Speed; Iceberg; Ice Surface Elevation; Non-Volcanic Tremor; Not provided; Antarctic; Iceberg Tremor; Solar Radiation; Antarctic Ice Sheet; Ross Ice Shelf; Elevation; GPS; Temperature Profiles; Ice Shelf Rift Camera; GROUND STATIONS; Latitude; GROUND-BASED OBSERVATIONS; Ice Shelf Weather; FIELD INVESTIGATION; ARWS; Surface Elevation; Ice Shelf Flow; Antarctica; FIELD SURVEYS; Camera; Seismometer; Iceberg Weather (aws); Ice Movement; Photo; Wind Direction; Iceberg Snow Accumulation; Tremor And Slow Slip Events; AWS Climate Data; Location; Iceberg Drift; Iceberg Collisions; Iceberg Tilt; Atmospheric Pressure; Iceberg Seismicity; Firn Temperature", "locations": "Antarctic; Antarctica; Antarctic Ice Sheet; Ross Ice Shelf", "north": -78.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Okal, Emile; Aster, Richard; Bassis, Jeremy; Kim, Young-Jin; Bliss, Andrew; Sergienko, Olga; Thom, Jonathan; Scambos, Ted; Muto, Atsu; Brunt, Kelly; King, Matthew; Parker, Tim; Okal, Marianne; Cathles, Mac; MacAyeal, Douglas", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e ARWS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND STATIONS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e SEISMOLOGICAL STATIONS; Not provided; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "USAP-DC", "repositories": "AMRDC; IRIS; NSIDC; Project website; USAP-DC", "science_programs": null, "south": -78.0, "title": "Collaborative Research of Earth\u0027s Largest Icebergs", "uid": "p0000117", "west": -178.0}, {"awards": "0338295 Tulaczyk, Slawek", "bounds_geometry": "POLYGON((-139 -82,-138.2 -82,-137.4 -82,-136.6 -82,-135.8 -82,-135 -82,-134.2 -82,-133.4 -82,-132.6 -82,-131.8 -82,-131 -82,-131 -82.08,-131 -82.16,-131 -82.24,-131 -82.32,-131 -82.4,-131 -82.48,-131 -82.56,-131 -82.64,-131 -82.72,-131 -82.8,-131.8 -82.8,-132.6 -82.8,-133.4 -82.8,-134.2 -82.8,-135 -82.8,-135.8 -82.8,-136.6 -82.8,-137.4 -82.8,-138.2 -82.8,-139 -82.8,-139 -82.72,-139 -82.64,-139 -82.56,-139 -82.48,-139 -82.4,-139 -82.32,-139 -82.24,-139 -82.16,-139 -82.08,-139 -82))", "dataset_titles": null, "datasets": null, "date_created": "Mon, 04 Aug 2008 00:00:00 GMT", "description": "This award supports a project to test whether Kamb Ice Stream (formerly Ice Stream C (ISC)), an ice stream\u003cbr/\u003ethat is thought to have stopped ~150 years ago, may be already in the process of restarting. If yes, it will help establish what is the rate of ice stream reactivation and what mechanisms are controlling this rate. If there is no evidence for ongoing ice stream reactivation, the physical controls that are preventing it will be examined and alternative scenarios for near-future evolution of this ice stream will be explored. One such scenario is an increase in ice diversion toward the neighboring Whillans Ice Stream. Such diversion may help prevent a complete stoppage of Whillans Ice Stream,which has been slowing down for at least the last 24 years. This project will consist of two components: (1) field observations of bed properties,geometry of internal radar reflectors, as well as surface strain rates and velocity/topography changes using Ice-Penetrating Radar and differential Global Positioning System, (2) numerical modeling study of near future(~100-1000 years) evolution of Kamb Ice Stream. The field component will be focused on the bulge-to-trunk transition, which is located at the present time just downstream of the so-called camp UpC. Reactivation of Kamb Ice Stream should be reflected in a downstream migration of the bulge-trunk transition at possibly high rates (bulge migration rates of ~km/yr occur on surging mountain glaciers). The modeling\u003cbr/\u003ecomponent will be used to generate predictions regarding the near-future behavior of Kamb Ice Stream. This project will provide training opportunities for at least two undergraduate students (per year) at St. Olaf College and for one\u003cbr/\u003eundergraduate student (per year) at UCSC. This collaboration will bring together scientists from three different types of US institutions: (1) a liberal arts college (St.Olaf College), (2) a public research university (UCSC) and (3) a NASA research laboratory (JPL). The project will also help build a new glaciological research program at UCSC. Project results will be incorporated into undergraduate and graduate courses at UCSC and will be made available\u003cbr/\u003eto the general public and educators through downloadable graphics and animations posted on the research website of the UCSC PI. Field data resulting from the project will be posted in the Antarctic Glaciological Data Center for use by other investigators.", "east": -131.0, "geometry": "POINT(-135 -82.4)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR", "is_usap_dc": false, "keywords": "Topography; GPS; Kamb Ice Stream; Ice Stream; FIELD SURVEYS; FIELD INVESTIGATION; Not provided; Ice Penetrating Radar; Ice Stream C; Velocity; Surface Strain Rates; Antarctic", "locations": "Antarctic; Kamb Ice Stream; Ice Stream C", "north": -82.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Tulaczyk, Slawek; Joughin, Ian", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided", "repositories": null, "science_programs": null, "south": -82.8, "title": "Collaborative Research: Is Kamb Ice Stream Restarting? Glaciological Investigations of the Bulge-Trunk Transition on Kamb Ice Stream, West Antarctica", "uid": "p0000238", "west": -139.0}, {"awards": "0540915 Scambos, Ted", "bounds_geometry": "POLYGON((-57.9857 -48.444,-55.95557 -48.444,-53.92544 -48.444,-51.89531 -48.444,-49.86518 -48.444,-47.83505 -48.444,-45.80492 -48.444,-43.77479 -48.444,-41.74466 -48.444,-39.71453 -48.444,-37.6844 -48.444,-37.6844 -50.12802,-37.6844 -51.81204,-37.6844 -53.49606,-37.6844 -55.18008,-37.6844 -56.8641,-37.6844 -58.54812,-37.6844 -60.23214,-37.6844 -61.91616,-37.6844 -63.60018,-37.6844 -65.2842,-39.71453 -65.2842,-41.74466 -65.2842,-43.77479 -65.2842,-45.80492 -65.2842,-47.83505 -65.2842,-49.86518 -65.2842,-51.89531 -65.2842,-53.92544 -65.2842,-55.95557 -65.2842,-57.9857 -65.2842,-57.9857 -63.60018,-57.9857 -61.91616,-57.9857 -60.23214,-57.9857 -58.54812,-57.9857 -56.8641,-57.9857 -55.18008,-57.9857 -53.49606,-57.9857 -51.81204,-57.9857 -50.12802,-57.9857 -48.444))", "dataset_titles": "Atlas of the Cryosphere - View dynamic maps of snow, sea ice, glaciers, ice sheets, permafrost, and more.; Climate, Drift, and Image Data from Antarctic Icebergs A22A and UK211, 2006-2007; MODIS Mosaic of Antarctica (MOA)", "datasets": [{"dataset_uid": "000189", "doi": "", "keywords": null, "people": null, "repository": "NSIDC", "science_program": null, "title": "Atlas of the Cryosphere - View dynamic maps of snow, sea ice, glaciers, ice sheets, permafrost, and more.", "url": "http://nsidc.org/MMS/atlas/cryosphere_atlas_north.html"}, {"dataset_uid": "000190", "doi": "", "keywords": null, "people": null, "repository": "NSIDC", "science_program": null, "title": "MODIS Mosaic of Antarctica (MOA)", "url": "http://nsidc.org/data/nsidc-0280.html"}, {"dataset_uid": "609466", "doi": "10.7265/N5N014GW", "keywords": "Ablation; Atmosphere; Glaciology; GPS; Meteorology; Oceans; Photo/video; Photo/Video; Sea Ice; Southern Ocean; Temperature", "people": "Thom, Jonathan; Scambos, Ted; Yermolin, Yevgeny; Bohlander, Jennifer; Bauer, Rob", "repository": "USAP-DC", "science_program": null, "title": "Climate, Drift, and Image Data from Antarctic Icebergs A22A and UK211, 2006-2007", "url": "https://www.usap-dc.org/view/dataset/609466"}], "date_created": "Thu, 16 Aug 2007 00:00:00 GMT", "description": "This award supports a small grant for exploratory research to study the processes that contribute to the melting and break-up of tabular polar icebergs as they drift north. This work will enable the participation of a group of U.S. scientists in this international project which is collaborative with the Instituto Antartico Argentino. The field team will place weather instruments, firn sensors, and a video camera on the iceberg to measure the processes that affect it as it drifts north. In contrast to icebergs in other sectors of Antarctica, icebergs in the northwestern Weddell Sea drift northward along relatively predictable paths, and reach climate and ocean conditions that lead to break-up within a few years. The timing of this study is critical due to the anticipated presence of iceberg A43A, which broke off the Ronne Ice Shelf in February 2000 and which is expected to be accessible from Marambio Station in early 2006. It has recently been recognized that the end stages of break-up of these icebergs can imitate the rapid disintegrations due to melt ponding and surface fracturing observed for the Larsen A and Larsen B ice shelves. However, in some cases, basal melting may play a significant role in shelf break-up. Resolving the processes (surface ponding/ fracturing versus basal melt) and observing other processes of iceberg drift and break up in-situ are of high scientific interest. An understanding of the mechanisms that lead to the distintegration of icebergs as they drift north may enable scientists to use icebergs as proxies for understanding the processes that could cause ice shelves to disintegrate in a warming climate. A broader impact would thus be an ability to predict ice shelf disintegration in a warming world. Glacier mass balance and ice shelf stability are of critical importance to sea level change, which also has broader societal relevance.", "east": -37.6844, "geometry": "POINT(-47.83505 -56.8641)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e ICE AUGERS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e SNOW DENSITY CUTTER; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e SPECTROMETERS/RADIOMETERS \u003e IMAGING SPECTROMETERS/RADIOMETERS \u003e MODIS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e CAMERAS \u003e CAMERAS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e MMS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e THERMOMETERS \u003e THERMOMETERS", "is_usap_dc": true, "keywords": "Air Temperature; Weddell Sea; Edge-Wasting; Ice Shelf Meltwater; TERRA; Antarctic; GPS; Iceberg; Ice Breakup; South Atlantic Ocean; AQUA; Tabular; Photo; Not provided; Icetrek; HELICOPTER; Antarctica", "locations": "Antarctic; Weddell Sea; Antarctica; South Atlantic Ocean", "north": -48.444, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Scambos, Ted; Bohlander, Jennifer; Bauer, Rob; Yermolin, Yevgeny; Thom, Jonathan", "platforms": "AIR-BASED PLATFORMS \u003e ROTORCRAFT/HELICOPTER \u003e HELICOPTER; Not provided; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e AQUA; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e TERRA; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "NSIDC", "repositories": "NSIDC; USAP-DC", "science_programs": null, "south": -65.2842, "title": "Investigating Iceberg Evolution During Drift and Break-Up: A Proxy for Climate-Related Changes in Antarctic Ice Shelves", "uid": "p0000003", "west": -57.9857}, {"awards": "9725882 Raymond, Charles", "bounds_geometry": "POLYGON((-141.6722 -80.1678,-141.34195 -80.1678,-141.0117 -80.1678,-140.68145 -80.1678,-140.3512 -80.1678,-140.02095 -80.1678,-139.6907 -80.1678,-139.36045 -80.1678,-139.0302 -80.1678,-138.69995 -80.1678,-138.3697 -80.1678,-138.3697 -80.4863,-138.3697 -80.8048,-138.3697 -81.1233,-138.3697 -81.4418,-138.3697 -81.7603,-138.3697 -82.0788,-138.3697 -82.3973,-138.3697 -82.7158,-138.3697 -83.0343,-138.3697 -83.3528,-138.69995 -83.3528,-139.0302 -83.3528,-139.36045 -83.3528,-139.6907 -83.3528,-140.02095 -83.3528,-140.3512 -83.3528,-140.68145 -83.3528,-141.0117 -83.3528,-141.34195 -83.3528,-141.6722 -83.3528,-141.6722 -83.0343,-141.6722 -82.7158,-141.6722 -82.3973,-141.6722 -82.0788,-141.6722 -81.7603,-141.6722 -81.4418,-141.6722 -81.1233,-141.6722 -80.8048,-141.6722 -80.4863,-141.6722 -80.1678))", "dataset_titles": "Radar Investigations of Antarctic Ice Stream Margins, Siple Dome, 1998", "datasets": [{"dataset_uid": "609303", "doi": "10.7265/N52B8VZP", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Radar; Siple Dome", "people": "Nereson, Nadine A.; Raymond, Charles", "repository": "USAP-DC", "science_program": "Siple Dome Ice Core", "title": "Radar Investigations of Antarctic Ice Stream Margins, Siple Dome, 1998", "url": "https://www.usap-dc.org/view/dataset/609303"}], "date_created": "Fri, 06 Jul 2007 00:00:00 GMT", "description": "9725882 Raymond This award is for support for a program of surface-based radio echo sounding to examine the geometry of the internal layering and the presence or absence of thawed zones outside the margins of active Ice Streams B and E and across the flow band feeding Ice Stream D. Melting in the marginal shear zone and/or on the bed outside an ice stream relates to the amount of support of the ice stream from the sides compared to the bed and the conditions that limit expansion of its width. Radar observations will be extended over the crest of adjacent inter-ice-stream ridges (B/C and D/E) and areas next to the flow band in the onset of D. The purpose is to examine internal layering indicative of the histories of these areas adjacent to ice streams and to determine whether ice streams have expanded into these presently stable areas in the past. These goals concerning the physical controls and history of ice stream width relate to how the discharge of ice streams has changed in the past and could change in the future to affect sea level.", "east": -138.3697, "geometry": "POINT(-140.02095 -81.7603)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS", "is_usap_dc": true, "keywords": "Ice Stream; Antarctica; Bed Geometry; GROUND-BASED OBSERVATIONS; Internal Layering; Internal Layer Geometry; Siple Dome; Shabtaie Ridge; Not provided; Engelhardt Ridge; Ice Stream Margins; Radar; Whillans Ice Stream; GPS; Bed Reflectivity; Macayeal Ice Stream; Surface Geometry", "locations": "Antarctica; Engelhardt Ridge; Macayeal Ice Stream; Shabtaie Ridge; Siple Dome; Whillans Ice Stream", "north": -80.1678, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Raymond, Charles; Nereson, Nadine A.", "platforms": "LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; Not provided; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": -83.3528, "title": "Internal Stratigraphy and Basal Conditions at the Margins ofActive Ice Streams of the Siple Coast, Antarctica", "uid": "p0000626", "west": -141.6722}, {"awards": "0125579 Cuffey, Kurt; 0126202 Blankenship, Donald", "bounds_geometry": "POLYGON((160 -77.6,160.25 -77.6,160.5 -77.6,160.75 -77.6,161 -77.6,161.25 -77.6,161.5 -77.6,161.75 -77.6,162 -77.6,162.25 -77.6,162.5 -77.6,162.5 -77.63,162.5 -77.66,162.5 -77.69,162.5 -77.72,162.5 -77.75,162.5 -77.78,162.5 -77.81,162.5 -77.84,162.5 -77.87,162.5 -77.9,162.25 -77.9,162 -77.9,161.75 -77.9,161.5 -77.9,161.25 -77.9,161 -77.9,160.75 -77.9,160.5 -77.9,160.25 -77.9,160 -77.9,160 -77.87,160 -77.84,160 -77.81,160 -77.78,160 -77.75,160 -77.72,160 -77.69,160 -77.66,160 -77.63,160 -77.6))", "dataset_titles": "Ablation Rates of Taylor Glacier, Antarctica; Stable Isotopes of Ice on the Surface of Taylor Glacier, Antarctica; Surface Velocities of Taylor Glacier, Antarctica", "datasets": [{"dataset_uid": "609324", "doi": "10.7265/N5RV0KM7", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Velocity; Taylor Glacier", "people": "Kavanaugh, Jeffrey; Cuffey, Kurt M.; Bliss, Andrew; Aciego, Sarah", "repository": "USAP-DC", "science_program": null, "title": "Surface Velocities of Taylor Glacier, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609324"}, {"dataset_uid": "609326", "doi": "10.7265/N5N29TW8", "keywords": "Ablation Poles; Ablation Rates; Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Taylor Glacier", "people": "Cuffey, Kurt M.; Kavanaugh, Jeffrey; Bliss, Andrew", "repository": "USAP-DC", "science_program": null, "title": "Ablation Rates of Taylor Glacier, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609326"}, {"dataset_uid": "609323", "doi": "10.7265/N5WM1BBZ", "keywords": "Antarctica; Chemistry:ice; Chemistry:Ice; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Isotope; Taylor Glacier", "people": "Cuffey, Kurt M.; Bliss, Andrew; Kavanaugh, Jeffrey; Aciego, Sarah", "repository": "USAP-DC", "science_program": null, "title": "Stable Isotopes of Ice on the Surface of Taylor Glacier, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609323"}], "date_created": "Tue, 13 Feb 2007 00:00:00 GMT", "description": "This award supports a project to significantly improve our understanding of how Taylor Glacier flows and responds to climate changes. Taylor Glacier drains the Taylor Dome region of the East Antarctic Ice Sheet and terminates in Taylor Valley, one of the Dry Valleys of Victoria Land. It provides a crucial and unique link between two intensively studied Antarctic environments: the Taylor Dome, from which a 130 kyr ice core paleoclimate record has recently been extracted, and the Dry Valleys, a pivotal Long-Term Ecological Research (LTER) site and a focus of research on geomorphology and glacial geology. The proposed work will thus make an important contribution to ongoing efforts to exploit the Taylor Dome - Dry Valleys system to build a uniquely comprehensive view of regional long-term environmental changes. The proposed work has two complementary components: field research and numerical modelling. Two field seasons will be used to measure velocity, surface strain rate, mass balance, ice thickness, glacier bed reflectance, and subglacial topography, along a nearly complete longitudinal transect of the Taylor Glacier, and along select cross-valley transects. This information will be used to constrain numerical models of ice and heat flow for the Taylor Dome - Taylor Glacier system. These calibrated models will be used to analyze the time-dependent response of the Taylor Glacier to climate changes. The synthesis of results will be aimed to improve understanding of the glacial geomorphology of Taylor Valley, and to illuminate impacts on the Taylor Valley lakes ecosystem. The project will have a major role in furthering the careers of a doctoral-level graduate student and a post-doctoral researcher.", "east": 162.5, "geometry": "POINT(161.25 -77.75)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS", "is_usap_dc": true, "keywords": "Glacier; Glacier Surface; Glacier Surface Ablation; Ice Velocity; Velocity Measurements; Taylor Glacier; Isotope; GPS; Ice Sheet Elevation; Not provided; FIELD INVESTIGATION; Ice Surface Elevation; Ablation; Oxygen Isotope; Elevation; Deuterium; GROUND-BASED OBSERVATIONS; Glacier Surface Ablation Rate; Surface Elevation", "locations": "Taylor Glacier", "north": -77.6, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Bliss, Andrew; Kavanaugh, Jeffrey; Aciego, Sarah; Cuffey, Kurt M.; Morse, David L.; Blankenship, Donald D.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; Not provided; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.9, "title": "Collaborative Research: Dynamics and Climatic Response of the Taylor Glacier System", "uid": "p0000084", "west": 160.0}]
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The evolution of surface and shallow subsurface meltwater across Antarctic ice shelves has important implications for their (in)stability, as demonstrated by the 2002 rapid collapse of the Larsen B Ice Shelf. It is vital to understand the causes of ice-shelf (in)stability because ice shelves buttress against the discharge of inland ice and therefore influence ice-sheet contributions to sea-level rise. Ice-shelf break-up may be triggered by stress variations associated with surface meltwater movement, ponding, and drainage. These variations may cause an ice shelf to flex and fracture. This four-year project will provide key geophysical observations to improve understanding of ice-shelf meltwater and its effects on (in)stability. The work will be conducted on the George VI Ice Shelf on the Antarctic Peninsula, where hundreds of surface lakes form each summer. Over a 27-month period, global positioning systems, seismometers, water pressure transducers, automatic weather stations, and in-ice thermistor strings will be deployed to record ice shelf flexure, fracture seismicity, water depths, and surface and subsurface melting, respectively, in and around several surface lakes on the George VI Ice Shelf, within roughly 20 km of the British Antarctic Survey's Fossil Bluff Station. Field data will be used to validate and extend the team's approach to modelling ice-shelf flexure and stress, and possible "Larsen-B style" ice-shelf instability and break-up. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Satellite observations of Earth’s surface gravity and elevation changes indicate rapid melting of ice sheets in recent decades in northern Antarctica Peninsula and Amundsen Sea Embayment of West Antarctica. This rapid melting may lead to significant global sea level rise which is a major societal concern. Measurements from the Global Positioning System (GPS) show rapid land uplift in these regions as the ice sheets melt. When an ice sheet melts, the melt water flows to oceans, causing global sea level to rise. However, the sea level change at a given geographic location is also influenced by two other factors associated with the ice melting process: 1) the vertical motion of the land and 2) gravitational attraction. The vertical motion of the land is caused by the change of pressure force on the surface of the solid Earth. For example, the removal of ice mass reduces the pressure force on the land, leading to uplift of the land below the ice sheet, while the addition of water in oceans increases the pressure force on the seafloor, causing it to subside. The sea level always follows the equipotential surface of the gravity which changes as the mass on the Earth’s surface (e.g., the ice and water) or/and in its interiors (e.g., at the crust-mantle boundary) is redistributed. Additionally, the vertical motion of the land below an ice sheet has important effects on the evolution and stability of the ice sheet and may determine whether the ice sheet will rapidly collapse or gradually stabilize. The main goal of this project is to build an accurate and efficient computer model to study the displacement and deformation of the Antarctic crust and mantle in response to recent ice melting. The project will significantly improve existing and publicly available computer code, CitcomSVE. The horizontal and vertical components of the Earth’s surface displacement depends on mantle viscosity and elastic properties of the Earth. Although seismic imaging studies demonstrate that the Antarctica mantle is heterogeneous, most studies on the ice-melting induced deformation in Antarctica have assumed that mantle viscosity and elastic properties only vary with the depth due to computational limitations. In this project, the new computational method in CitcomSVE avoids such assumptions and makes it possible to include realistic 3-D mantle viscosity and elastic properties in computing the Antarctica crustal and mantle displacement. This project will interpret the GPS measurements of the surface displacements in northern Antarctica Peninsula and Amundsen Sea Embayment of West Antarctica and use the observations to place constraints on mantle viscosity and deformation mechanisms. The project will also seek to predict the future land displacement Antarctica, which will lead to a better understand of Antarctica ice sheets. Finally, the project has direct implications for the study of global sea level change and the dynamics of the Greenland ice sheet. Technical Description Glacial isostatic adjustment (GIA) is important for understanding not only fundamental science questions including mantle viscosity, mantle convection and lithospheric deformation but also societally important questions of global sea-level change, polar ice melting, climate change, and groundwater hydrology. Studies of rock deformation in laboratory experiments, post-seismic deformation, and mantle dynamics indicate that mantle viscosity is temperature- and stress-dependent. Although the effects of stress-dependent (i.e., non-Newtonian) viscosity and transient creep rheology on GIA process have been studied, observational evidence remains elusive. There has been significant ice mass loss in recent decades in northern Antarctica Peninsula (NAP) and Amundsen Sea Embayment (ASE) of West Antarctica. The ice mass loss has caused rapid bedrock uplift as measured by GPS techniques which require surprisingly small upper mantle viscosity of ~1018 Pas. The rapid uplifts may have important feedback effects on ongoing ice melting because of their influence on grounding line migration, and the inferred small viscosity may have implications for mantle rheology and deformation on decadal time scales. The main objective of the project is to test hypotheses that the GPS observations in NAP and ASE regions are controlled by 3-D non-Newtonian or/and transient creep viscosity by developing new GIA modeling capability based on finite element package CitcomSVE. The project will carry out the following three tasks: Task 1 is to build GIA models for the NAP and ASE regions to examine the effects of 3-D temperature-dependent mantle viscosity on the surface displacements and to test hypothesis that the 3-D mantle viscosity improves the fit to the GPS observations. Task 2 is to test the hypothesis that non-Newtonian or/and transient creep rheology controls GIA process on decadal time scales by computing GIA models and comparing model predictions with GPS observations for the NAP and ASE regions. Task 3 is to implement transient creep (i.e., Burgers model) rheology into finite element package CitcomSVE for modeling the GIA process on global and regional scales and to make the package publicly available to the scientific community. The project will develop the first numerical GIA model with Burgers transient rheology and use the models to examine the effects of 3-D temperature-dependent viscosity, non-Newtonian viscosity and transient rheology on GIA-induced surface displacements in Antarctica. The project will model the unique GPS observations of unusually large displacement rates in the NAP and ASE regions to place constraints on mantle rheology and to distinguish between 3-D temperature-dependent, non-Newtonian and transient mantle viscosity. The project will expand the capability of the publicly available software package CitcomSVE for modeling viscoelastic deformation and tidal deformation on global and regional scales. The project will advance our understanding in lithospheric deformation and mantle rheology on decadal time scales, which helps predict grounding line migration and understand ice sheet stability in West Antarctica. The project will strengthen the open science practice by improving the publicly available code CitcomSVE at github. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Part I: Non-technical description: Understanding human-induced changes on biodiversity is one of the most important scientific challenges we face today. This is especially true for marine environments that are home to much of the world’s biomass and biodiversity. A particularly effective approach to investigate the effects of climate change on marine ecosystems is to monitor top-predator populations such as seabirds or marine mammals. The food web in the Southern Ocean in relatively small and involves few species, therefore climate-induced variations at the prey species level directly affect the predator species level. For example, seabirds, like penguins, are ideal to detect and study these ecosystem changes. This study combines traditional methods to study emperor penguin population dynamics with the use of an autonomous vehicle to conduct the population dynamic measurements with less impact and higher accuracy. This project leverages an existing long-term emperor penguin observatory at the Atka Bay colony which hosts penguins living in the Weddell sea and the Atlantic sector of the Southern Ocean. The study will kickstart the collection of a multi-decadal data set in an area of the Southern Ocean that has been understudied. It will fill important gaps in ecological knowledge on the state of the Emperor penguin and its adaptive capabilities within a changing world. Finally, the project supports NSF goals of training new generations of scientists through collaborative training of undergraduate students and the creation of a new class on robotics for ecosystem study. Emperor penguins are an iconic species that few people will ever see in the wild. Through the technology developed in this proposal, the public can be immersed in real-time into the life of an emperor penguin colony. Public outreach will be achieved by showcasing real-time video and audio footage of emperor penguins from the field as social media science and engineering-themed educational materials. Part II: Technical description: Polar ecosystems currently experience significant impacts due to global changes. Measurable negative effects on polar wildlife have already occurred, such as population decreases of numerous seabird species, including the complete loss of colonies of one of the most emblematic species of the Antarctic, the emperor penguin. These existing impacts on polar species are alarming, especially because many polar species still remain poorly studied due to technical and logistical challenges imposed by the harsh environment and extreme remoteness. Developing technologies and tools for monitoring such wildlife populations is, therefore, a matter of urgency. This project aims to help close major knowledge gaps about the emperor penguin, in particular about their adaptive capability to a changing environment, by the development of next-generation tools to remotely study entire colonies. Specifically, the main goal of this project is to implement and test an autonomous unmanned ground vehicle equipped with Radio-frequency identification (RFID) antennas and wireless mesh communication data-loggers to: 1) identify RFID-tagged emperor penguins during breeding to studying population dynamics without human presence; and 2) receive Global Positioning System-Time Domain Reflectometry (GPS-TDR) datasets from Very High Frequency VHF-GPS-TDR data-loggers without human presence to study animal behavior and distribution at sea. The autonomous vehicles navigation through the colony will be aided by an existing remote penguin observatory (SPOT). Properly implemented, this technology can be used to study of the life history of individual penguins, and therefore gather data for behavioral and population dynamic studies. The new data will contribute to intelligent establishment of marine protected areas in Antarctica. The education objectives of this CAREER project are designed to increase the interest in a STEM education for the next generation of scientists by combining the charisma of the emperor penguin with robotics research. Within this project, a new class on ecosystem robotics will be developed and taught, Robotics boot-camps will allow undergraduate students to remotely participate in Antarctic field trips, and an annual curriculum will be developed that allows K-12 students to follow the life of the emperor penguin during the breeding cycle, powered by real-time data obtained using the unmanned ground vehicle as well as the existing emperor penguin observatory. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Licht/1443433 Sediments deposited by the Antarctic ice sheet are an archive of its history with time and help geologists to determine how the remote interior of the ice sheet has changed over the past several hundred thousand years. This project will focus on the formation and dynamics of moraines (accumulations of dirt and rocks that are incorporated in the glacier surface or have been pushed along by the glacier as it moves) near the blue ice area of Mt. Achernar in the central Transantarctic Mountains in Antarctica.. The study will improve basic understanding of the formation of these moraines. Fieldwork at the site will focus on imaging the internal structure of the moraine to determine the processes by which it, and others like it, form over time. Additional analyses will include measurements of ice flow and collection of rock samples to determine the timing of debris deposition and the changes in the sources of sediments from deep within the Antarctic continent. The project will provide both graduate and undergraduate students training in paleoclimate studies, geology, and numerical modeling approaches. The broader impacts of the proposed work include hands on training in the Earth Sciences for graduate and undergraduate students, collaboration with colleagues in New Zealand and Sweden to provide an international research experience for students from the US, and three educational modules to be delivered by student researchers regarding Antarctica's role in global environments. The research is societally relevant and multidisciplinary and the topics are ideal for sharing with the public. All research findings will be made publicly available to others via timely publication in high-impact, peer-reviewed journals and all data will be submitted to the National Snow and Ice Data Center, and excess samples will be provided to the U.S. Polar Rock Repository. Direct observations of ice sheet history from the margins of Antarctica's polar plateau are essential for testing numerical ice sheet models, and the laterally extensive, blue-ice moraines of the Mt. Achernar Moraine complex in the central Transantarctic Mountains contain a unique and nearly untapped direct, quasi-continuous record of ice sheet change over multiple glacial cycles. The project objectives include improved understanding of processes and rates of blue ice moraine formation, as well as identifying the topographic, glaciological, and climatic controls on their evolution. Data to be collected with fieldwork in Antarctica include: imaging of internal ice structure with ground-penetrating radar, measurement of ice flow velocity and direction with a global positioning system (GPS) array, analysis of debris concentration and composition in glacier ice, state-of-the-art cosmogenic multi-nuclide analyses to determine exposure ages of moraine debris, mapping of trimlines and provenance analysis. Numerical model simulations, constrained by field data, will be used to evaluate the factors influencing changes in glacier flow that potentially impact the accumulation of the moraine debris. All together, the new data and modeling efforts will improve conceptual models of blue ice moraine formation, and thereby make them a more valuable proxy for developing a better understanding of the history of the ice sheet.
Meltwater lakes that sit on top of Antarctica's floating ice shelves have likely contributed to the dramatic changes seen in Antarctica's glacial ice cover over the past two decades. In 2002, the 1,600-square-kilometer Larsen B Ice Shelf located on the Eastern side of the Antarctic Peninsula, for example, broke into thousands of small icebergs, which subsequently floated away as a result of the formation of more than 2,000 meltwater lakes on its surface over the prior decade. Our research project addresses the reasons why surface lakes form on Antarctic ice shelves and how these surface lakes subsequently contribute to the forces that may contribute to ice-shelf breakup like that of the Larsen B. Our project focuses primarily on making precise global positioning system (GPS) measurements of ice-shelf bending in response to the filling and draining of a surface lake on the McMurdo Ice Shelf. The observed vertical displacements (on the order of tens of centimeters) in response to lake filling will be used to calibrate and test computer simulation models that predict the response of ice shelves to surface lakes more generally and in a variety of future climate conditions. Our project will make hourly measurements of both vertical ice-shelf movements (using GPS surveying instruments) and of temperature and sunlight conditions (that drive melting) around a surface lake located close to the McMurdo Station airfield. Following this initial data-gathering effort, computer simulations and other more theoretical analysis will be undertaken to determine the suitability of the chosen McMurdo Ice Shelf surface lake as a field-laboratory for continued study. Ultimately, the research will contribute to understanding of the glaciological processes that link climate change to rising sea level. A successful outcome of the research will allow glaciologists to better assess the processes that promote or erode the influence Antarctic ice shelves have in controlling the transfer of ice from the interior of Antarctica into the ocean. The project will undertake two outreach activities: (1) web-posting of a field-activity journal and (2) establishing an open-access glaciological teaching and outreach web-sharing site for the International Glaciological Society. The proposed project seeks to experimentally verify a theory of ice-shelf instability proposed to explain the explosive break-up of Larsen B Ice Shelf in 2002. This theory holds that the filling and draining of supraglacial lakes on floating ice shelves induces sufficient flexure stress within the ice to (a) induce upward/downward propagating fractures originating at the base/surface of the ice shelf that (b) dissect the ice shelf into fragments that tend to have widths less than about half the ice thickness. The significance of narrow widths is that they promote capsize of the ice-shelf fragments during the break-up process. This capsize releases large amounts of gravitational potential energy (comparable to thousands of kilotons of TNT for the Larsen B Ice Shelf) thereby promoting explosiveness of the Larsen B event. The observational motivation for experimentally verifying the surface-lake mechanism for ice-shelf breakup is based on the fact that >2,000 surface lakes developed on the Larsen B Ice Shelf in the decade prior to its break up, and that these lakes were observed (via satellite imagery) to drain in a coordinated fashion during the day prior to the initiation of the break up. The field-observation component of the project will focus on a supraglacial lake on the McMurdo Ice Shelf where there is persistent summer season surface melting. The lake will be studied during a single provisional field season to determine whether grooming of surrounding surface streams and shorelines with heavy construction equipment will allow surface water to be manually encouraged to fill the lake. If successfully encouraged to develop, the McMurdo Ice Shelf surface lake will allow measurements of key ice-shelf flexure and stress variables needed to develop the theory of ice-shelf surface lakes without having to access the much more logistically demanding surface lakes of ice-shelves located elsewhere in Antarctica. Data to be gathered during the 6-week provisional field season include: energy- and water-balance parameters determining how the surface lake grows and fills, and various global positioning system measurements of the vertical bending of the ice sheet in response to the changing meltwater load contained within the surface lake. These data will be used to (1) constrain a computer model of viscoelastic flexure and possible fracture of the ice shelf in response to the increasing load of meltwater in the lake, and (2) determine whether continued study of the incipient surface-meltwater lake features on the McMurdo Ice Shelf provides a promising avenue for constraining the more-general behavior of surface meltwater lakes on other ice shelves located in warmer parts of Antarctica. Computer models constrained by the observational data obtained from the field project will inform energy- and water-balance models of ice shelves in general, and allow more accurate forecasts of changing ice-shelf conditions surrounding the inland ice of Antarctica. The project will create the first-ever ground-based observations useful for spawning the development of models capable of predicting viscoelastic and fracture behavior of ice shelves in response to supraglacial lake evolution, including slow changes due to energy balance effects, as well as fast changes due to filling and draining.
This project aims to identify which portions of the glacial cover in the Antarctic Peninsula are losing mass to the ocean. This is an important issue to resolve because the Antarctic Peninsula is warming at a faster rate than any other region across the earth. Even though glaciers across the Antarctic Peninsula are small, compared to the continental ice sheet, defining how rapidly they respond to both ocean and atmospheric temperature rise is critical. It is critical because it informs us about the exact mechanisms which regulate ice flow and melting into the ocean. For instance, after the break- up of the Larsen Ice Shelf in 2002 many glaciers began to flow rapidly into the sea. Measuring how much ice was involved is difficult and depends upon accurate estimates of volume and area. One way to increase the accuracy of our estimates is to measure how fast the Earth's crust is rebounding or bouncing back, after the ice has been removed. This rebound effect can be measured with very precise techniques using instruments locked into ice free bedrock surrounding the area of interest. These instruments are monitored by a set of positioning satellites (the Global Positioning System or GPS) in a continuous fashion. Of course the movement of the Earth's bedrock relates not only to the immediate response but also the longer term rate that reflects the long vanished ice masses that once covered the entire Antarctic Peninsula?at the time of the last glaciation. These rebound measurements can, therefore, also tell us about the amount of ice which covered the Antarctic Peninsula thousands of years ago. Glacial isostatic rebound is one of the complicating factors in allowing us to understand how much the larger ice sheets are losing today, something that can be estimated by satellite techniques but only within large errors when the isostatic (rebound) correction is unknown. The research proposed consists of maintaining a set of six rebound stations until the year 2016, allowing for a longer time series and thus more accurate estimates of immediate elastic and longer term rebound effects. It also involves the establishment of two additional GPS stations that will focus on constraining the "bull's eye" of rebound suggested by measurements over the past two years. In addition, several more geologic data points will be collected that will help to reconstruct the position of the ice sheet margin during its recession from the full ice sheet of the last glacial maximum. These will be based upon the coring of marine sediment sequences now recognized to have been deposited along the margins of retreating ice sheets and outlets. Precise dating of the ice margin along with the new and improved rebound data will help to constrain past ice sheet configurations and refine geophysical models related to the nature of post glacial rebound. Data management will be under the auspices of the UNAVCO polar geophysical network or POLENET and will be publically available at the time of station installation. This project is a small scale extension of the ongoing LARsen Ice Shelf, Antarctica Project (LARISSA), an IPY (International Polar Year)-funded interdisciplinary study aimed at understanding earth system connections related to the Larsen Ice Shelf and the northern Antarctic Peninsula.
This project constructs POLENET a network of GPS and seismic stations in West Antarctica to understand how the mass of the West Antarctic ice sheet (WAIS) changes with time. The information is ultimately used to predict sea level rise accompanying global warming and interpret climate change records. The GPS (global positioning system) stations measure vertical and horizontal movements of bedrock, while the seismic stations characterize physical properties of the ice/rock interface, lithosphere, and mantle. Combined with satellite data, this project offers a more complete picture of the ice sheet's current state, its likely change in the near future, and its overall size during the last glacial maximum. This data will also be used to infer sub-ice sheet geology and the terrestrial heat flux, critical inputs to models of glacier movement. As well, this project improves tomographic models of the earth's deep interior and core through its location in the Earth's poorly instrumented southern hemisphere. <br/><br/><br/><br/>Broader impacts of this project are varied. The work is relevant to society for improving our understanding of the impacts of global warming on sea level rise. It also supports education at the postdoctoral, graduate, and undergraduate levels, and outreach to groups underrepresented in the sciences. As an International Polar Year contribution, this project establishes a legacy of infrastructure for polar measurements. It also involves an international collaboration of twenty four countries. For more information see IPY Project #185 at IPY.org. NSF is supporting a complementary Arctic POLENET array being constructed in Greenland under NSF Award #0632320.
This award supports a field experiment, with partners from Chile and the Netherlands, to determine the state of health and stability of Larsen C ice shelf in response to climate change. Significant glaciological and ecological changes are taking place in the Antarctic Peninsula in response to climate warming that is proceeding at 6 times the global average rate. Following the collapse of Larsen A ice shelf in 1995 and Larsen B in 2002, the outlet glaciers that nourished them with land ice accelerated massively, losing a disproportionate amount of ice to the ocean. Further south, the much larger Larsen C ice shelf is thinning and measurements collected over more than a decade suggest that it is doomed to break up. The intellectual merit of the project will be to contribute to the scientific knowledge of one of the Antarctic sectors where the most significant changes are taking place at present. The project is central to a cluster of International Polar Year activities in the Antarctic Peninsula. It will yield a legacy of international collaboration, instrument networking, education of young scientists, reference data and scientific analysis in a remote but globally relevant glaciological setting. The broader impacts of the project will be to address the contribution to sea level rise from Antarctica and to bring live monitoring of climate and ice dynamics in Antarctica to scientists, students, the non-specialized public, the press and the media via live web broadcasting of progress, data collection, visualization and analysis. Existing data will be combined with new measurements to assess what physical processes are controlling the weakening of the ice shelf, whether a break up is likely, and provide baseline data to quantify the consequences of a breakup. Field activities will include measurements using the Global Positioning System (GPS), installation of automatic weather stations (AWS), ground penetrating radar (GPR) measurements, collection of shallow firn cores and temperature measurements. These data will be used to characterize the dynamic response of the ice shelf to a variety of phenomena (oceanic tides, iceberg calving, ice-front retreat and rifting, time series of weather conditions, structural characteristics of the ice shelf and bottom melting regime, and the ability of firn to collect melt water and subsequently form water ponds that over-deepen and weaken the ice shelf). This effort will complement an analysis of remote sensing data, ice-shelf numerical models and control methods funded independently to provide a more comprehensive analysis of the ice shelf evolution in a changing climate.
This award supports a project to investigate fabrics with ground-based radar measurements near the Ross/Amundsen Sea ice-flow divide where a deep ice core will be drilled. The alignment of crystals in ice (crystal-orientation fabric) has an important effect on ice deformation. As ice deforms, anisotropic fabrics are produced, which, in turn, influence further deformation. Measurement of ice fabric variations can help reveal the deformation history of the ice and indicate how the ice will deform in the future. Ice cores provide opportunities to determine a vertical fabric profile, but horizontal variations of fabrics remain unknown. Remote sensing with ice-penetrating radar is the only way to do that over large areas. Preliminary results show that well-established polarimetric methods can detect the degree of horizontal anisotropy of fabrics and their orientation, even when they are nearly vertical-symmetric fabrics. In conjunction with ice deformation history, our first mapping of ice fabrics will contribute to modeling ice flow near the future ice core site. The project will train a graduate student and provide research experiences for two under graduate students both in field and laboratory. The project will contribute to ongoing West Antarctic ice sheet program efforts to better understand the impact of the ice sheet on global sea level rise. This project also supports an international collaboration between US and Japanese scientists.
0538120<br/>Catania<br/>This award supports a project to identify and map ice surface and internal features that chronicle the sequence of events leading to the shut-down of Kamb ice stream. In particular, the project will study past grounding line migration and the relationship between that process and ice stream shutdown. The intellectual merits of the project include the fact that an understanding of such processes has important implications for our ability to accurately predict mass balance changes in this region. Currently, one of the five major West Antarctic ice streams, Kamb, is quiescent, and another, Whillans, is slowing in its downstream reaches. The Kamb shutdown appears to have begun at its downstream end but beyond that simple observation, it is not possible, yet, to draw meaningful comparisons between the two adjacent streams. We do not know if current events on Whillans Ice Stream are similar to what transpired during the Kamb shut-down. The work proposed here intends to bridge that gap. It is expected that this effort will yield useful insights into the influence of grounding line dynamics on ice stream flow. The work will involve a combination of field investigations using radio-echo sounding and GPS combined with computational efforts involving the interpretation of ice-surface features such as relict flow traces and crevasses. The broader impacts of the project will be in addressing a global environmental problem with critical societal implications, training the next generation of scientists and engineers to serve the nation, and encouraging women to pursue scientific or engineering careers. Participants from both institutions are involved in a range of public outreach activities.
This award supports a project to test whether Kamb Ice Stream (formerly Ice Stream C (ISC)), an ice stream<br/>that is thought to have stopped ~150 years ago, may be already in the process of restarting. If yes, it will help establish what is the rate of ice stream reactivation and what mechanisms are controlling this rate. If there is no evidence for ongoing ice stream reactivation, the physical controls that are preventing it will be examined and alternative scenarios for near-future evolution of this ice stream will be explored. One such scenario is an increase in ice diversion toward the neighboring Whillans Ice Stream. Such diversion may help prevent a complete stoppage of Whillans Ice Stream,which has been slowing down for at least the last 24 years. This project will consist of two components: (1) field observations of bed properties,geometry of internal radar reflectors, as well as surface strain rates and velocity/topography changes using Ice-Penetrating Radar and differential Global Positioning System, (2) numerical modeling study of near future(~100-1000 years) evolution of Kamb Ice Stream. The field component will be focused on the bulge-to-trunk transition, which is located at the present time just downstream of the so-called camp UpC. Reactivation of Kamb Ice Stream should be reflected in a downstream migration of the bulge-trunk transition at possibly high rates (bulge migration rates of ~km/yr occur on surging mountain glaciers). The modeling<br/>component will be used to generate predictions regarding the near-future behavior of Kamb Ice Stream. This project will provide training opportunities for at least two undergraduate students (per year) at St. Olaf College and for one<br/>undergraduate student (per year) at UCSC. This collaboration will bring together scientists from three different types of US institutions: (1) a liberal arts college (St.Olaf College), (2) a public research university (UCSC) and (3) a NASA research laboratory (JPL). The project will also help build a new glaciological research program at UCSC. Project results will be incorporated into undergraduate and graduate courses at UCSC and will be made available<br/>to the general public and educators through downloadable graphics and animations posted on the research website of the UCSC PI. Field data resulting from the project will be posted in the Antarctic Glaciological Data Center for use by other investigators.
This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a collaborative research program to initiate a Global Positioning System (GPS) network to measure crustal motions in the bedrock surrounding and underlying the West Antarctic Ice Sheet (WAIS). Evaluation of the role of both tectonic and ice-induced crustal motions of the WAIS bedrock is a critical goal for understanding past, present, and future dynamics of WAIS and its potential role in future global change scenarios, as well as improving our understanding of the role of Antarctica in global plate motions. The extent of active tectonism in West Antarctica is largely speculative, as few data exist that constrain its geographic distribution, directions, or rates of deformation. Active tectonism and the influence of bedrock on the WAIS have been highlighted recently by geophysical data indicating active subglacial volcanism and control of ice streaming by the presence of sedimentary basins. The influence of bedrock crustal motion on the WAIS and its future dynamics is a fundamental issue. Existing GPS projects are located only on the fringe of the ice sheet and do not address the regional picture. It is important that baseline GPS measurements on the bedrock around and within the WAIS be started so that a basis is established for detecting change.<br/><br/>To measure crustal motions, this project will build a West Antarctica GPS Network (WAGN) of at least 15 GPS sites across the interior of West Antarctica (approximately the size of the contiguous United States from the Rocky Mountains to the Pacific coast) over a two-year period beginning in the Antarctic field season 2001-2002. The planned network is designed using the Multi-modal Occupation Strategy (MOST), in which a small number of independent GPS "roving" receivers make differential measurements against a network of continuous GPS stations for comparatively short periods at each site. This experimental strategy, successfully implemented by a number of projects in California, S America, the SW Pacific and Central Asia, minimizes logistical requirements, an essential element of application of GPS geodesy in the scattered and remote outcrops of the WAIS bedrock.<br/><br/>The WAGN program will be integrated with the GPS network that has been established linking the Antarctic Peninsula with South America through the Scotia arc (Scotia Arc GPS Project (SCARP)). It will also interface with stations currently measuring motion across the Ross Embayment, and with the continent-wide GIANT program of the Working Group on Geodesy and Geographic Information Systems of the Scientific Committee on Antarctic Research (SCAR). The GPS network will be based on permanent monuments set in solid rock outcrops that will have near-zero set-up error for roving GPS occupations, and that can be directly converted to a continuous GPS site when future technology makes autonomous operation and satellite data linkage throughout West Antarctica both reliable and economical. The planned network both depends on and complements the existing and planned continuous networks. It is presently not practical, for reasons of cost and logistics, to accomplish the measurements proposed herein with either a network of continuous stations or traditional campaigns.<br/><br/>The proposed WAGN will complement existing GPS projects by filling a major gap in coverage among several discrete crustal blocks that make up West Antarctica, a critical area of potential bedrock movements. If crustal motions are relatively slow, meaningful results will only begin to emerge within the five-year maximum period of time for an individual funded project. Hence this proposal is only to initiate the network and test precision and velocities at the most critical sites. Once built, however, the network will yield increasingly meaningful results with the passage of time. Indeed, the slower the rates turn out to be, the more important an early start to measuring. It is anticipated that the results of this project will initiate an iterative process that will gradually resolve into an understanding of the contributions from plate rotations and viscoelastic and elastic motions resulting from deglaciation and ice mass changes. Velocities obtained from initial reoccupation of the most critical sites will dictate the timing of a follow-up proposal for reoccupation of the entire network when detectable motions have occurred.
This award supports development of a new modeling approach that will extract information about past snow accumulation rate in both space and time in the vicinity of the future ice core near the Ross-Amundsen divide of the West Antarctic Ice Sheet (WAIS). Internal layers, detected by ice-penetrating radar, are isochrones, or former ice-sheet surfaces that have been buried by subsequent snowfall, and distorted by ice flow. Extensive ice-penetrating radar data are available over the inland portion of the WAIS. Layers have been dated back to 17,000 years before present. The radar data add the spatial dimension to the temporally resolved accumulation record from ice cores. Accumulation rates are traditionally derived from the depths of young, shallow layers, corrected for strain using a local 1-D ice-flow model. Older, deeper layers have been more affected by flow over large horizontal distances. However, it is these deeper layers that contain information on longer-term climate patterns. This project will use geophysical inverse theory and a 2.5D flow-band ice-flow forward model comprising ice-surface and layer-evolution modules, to extract robust transient accumulation patterns by assimilating multiple deeper, more-deformed layers that have previously been intractable. Histories of divide migration, geothermal flux, and surface evolution will also be produced. The grant will support the PhD research of a female graduate student who is a mentor to female socio-economically disadvantaged high-school students interested in science, through the University of Washington Women's Center. It will also provide a research<br/>experience for an undergraduate student, and contribute to a freshman seminar on Scientific Research.
OPP-0230285/OPP-0230356<br/>PIs: Wilson, Terry J./Hothem, Larry D.<br/><br/>This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a project to conduct GPS measurements of bedrock crustal motions in an extended Transantarctic Mountains Deformation network (TAMDEF) to document neotectonic displacements due to tectonic deformation within the West Antarctic rift and/or to mass change of the Antarctic ice sheets. Horizontal displacements related to active neotectonic rifting, strike-slip translations, and volcanism will be tightly constrained by monitoring the combined TAMDEF and Italian VLNDEF networks of bedrock GPS stations along the Transantarctic Mountains and on offshore islands in the Ross Sea. Glacio-isostatic adjustments due to deglaciation since the Last Glacial Maximum and to modern mass change of the ice sheets will be modeled from GPS-derived crustal motions together with new information from other programs on the configurations, thicknesses, deglaciation history and modern mass balance of the ice sheets. Tectonic and rheological information from ongoing structural and seismic investigations in the Victoria Land region will also be integrated in the modeling. The integrative and iterative modeling will yield a holistic interpretation of neotectonics and ice sheet history that will help us to discriminate tectonic crustal displacements from viscoelastic/elastic glacio-isostatic motions. These results will provide key information to interpret broad, continental-scale crustal motion patterns detected by sparse, regionally distributed GPS continuous trackers and by spaceborne instruments. This study will contribute to international programs focused on Antarctic neotectonic and global change issues.<br/><br/>Strategies to meet these science objectives include repeat surveys of key sites in the existing TAMDEF network, extension of the array of TAMDEF sites southward about 250 km along the Transantarctic Mountains, linked measurements with the VLNDEF network, and integration of quasi-continuous trackers within the campaign network. By extending the array of bedrock sites southward, these measurements will cross gradients in predicted vertical motion due to viscoelastic rebound. The southward extension will also allow determination of the southern limit of the active Terror Rift and will provide a better baseline for constraints on any ongoing tectonic displacements across the West Antarctic rift system as a whole that might be possible using GPS data collected by the West Antarctic GPS Network. This project will also investigate unique aspects of GPS geodesy in Antarctica to determine how the error spectrum compares to mid-latitude regions and to identify the optimum measurement and data processing schemes for Antarctic conditions. The geodetic research will improve position accuracies within our network and will also yield general recommendations for deformation monitoring networks in polar regions.<br/><br/>An education and outreach program is planned and will be targeted at non-science-major undergraduate students taking Earth System Science at Ohio State University. The objective will be to illuminate the research process for nonscientists. This effort will educate students on the process of science and inform them about Antarctica and how it relates to global science issues.
This award supports a project to collect and develop high-resolution ice core records from the Dry Valleys region of Antarctica, and provide interpretations of interannual to decadal-scale climate variability during the last 2000 years (late Holocene). The project will test hypotheses related to ocean/atmosphere teleconnections (e.g., El Nino Southern Oscillation, Antarctic Oscillation) that may be responsible for major late Holocene climate events such as the Little Ice Age in the Southern Hemisphere. Conceptual and quantitative models of these processes in the Dry Valleys during the late Holocene are critical for understanding recent climate changes, and represent the main scientific merit of the project. We plan to collect intermediate-length ice cores (100-200m) at four sites along transects in Taylor Valley and Wright Valley, and analyze each core at high resolution for stable isotopes (d18O, dD), major ions (Na+, Mg2+, Ca2+, K+, NH4+, Cl-, NO3-, SO42-, MSA), and trace elements (Al, Fe, S, Sr, B). A suite of statistical techniques will be applied to the multivariate glaciochemical dataset to identify chemical associations and to calibrate the time-series records with available instrumental data. Broader impacts of the project include: 1) contributions to several ongoing interdisciplinary Antarctic research programs; 2) graduate and undergraduate student involvement in field, laboratory, and data interpretation activities; 3) use of project data and ideas in several UMaine courses and outreach activities; and 4) data dissemination through peer-reviewed publications, UMaine and other paleoclimate data archive websites, and presentations at national and international meetings.
This award supports the study of the drift and break-up of Earth's largest icebergs, which were recently released into the Ross Sea of Antarctica as a result of calving from the Ross Ice Shelf. The scientific goals of the study are to determine the physics of iceberg motion within the dynamic context of ocean currents, winds, and sea ice, which determine the forces that drive iceberg motion, and the relationship between the iceberg and geographically and topographically determined pinning points on which the iceberg can ground. In addition, the processes by which icebergs influence the local environments (e.g., sea ice conditions near Antarctica, access to penguin rookeries, air-sea heat exchange and upwelling at iceberg margins, nutrient fluxes) will be studied. The processes by which icebergs generate globally far-reaching ocean acoustic signals that are detected within the global seismic (earthquake) sensing networks will also be studied. A featured element of the scientific research activity will be a field effort to deploy automatic weather stations, seismometer arrays and GPS-tracking stations on several of the largest icebergs presently adrift, or about to be adrift, in the Ross Sea. Data generated and relayed via satellite to home institutions in the Midwest will motivate theoretical analysis and computer simulation; and will be archived on an "iceberg" website (http://amrc.ssec.wisc.edu/amrc/iceberg.html) for access by scientists and the general public. At the most broad level, the study is justified by the fact that icebergs released by the Antarctic ice sheet represent the largest movements of fresh water within the natural environment (e.g., several of the icebergs to be studied, B15, C19 and others calved since 2000 CE, represent over 6000 cubic kilometers of fresh water-an amount roughly equivalent to 100 years of the flow of the Nile River). A better understanding of the impact of iceberg drift through the environment, and particularly the impact on ocean stratification and mixing, is essential to the understanding of the abrupt global climate changes witnessed by proxy during the ice age and of concern under conditions of future greenhouse warming. On a more specific level, the study will generate a knowledge base useful for the better management of Antarctic logistical resources (e.g., the shipping lanes to McMurdo Station) that can occasionally be influenced by adverse effects icebergs have on sea ice conditions.
This award supports a project to test whether Kamb Ice Stream (formerly Ice Stream C (ISC)), an ice stream<br/>that is thought to have stopped ~150 years ago, may be already in the process of restarting. If yes, it will help establish what is the rate of ice stream reactivation and what mechanisms are controlling this rate. If there is no evidence for ongoing ice stream reactivation, the physical controls that are preventing it will be examined and alternative scenarios for near-future evolution of this ice stream will be explored. One such scenario is an increase in ice diversion toward the neighboring Whillans Ice Stream. Such diversion may help prevent a complete stoppage of Whillans Ice Stream,which has been slowing down for at least the last 24 years. This project will consist of two components: (1) field observations of bed properties,geometry of internal radar reflectors, as well as surface strain rates and velocity/topography changes using Ice-Penetrating Radar and differential Global Positioning System, (2) numerical modeling study of near future(~100-1000 years) evolution of Kamb Ice Stream. The field component will be focused on the bulge-to-trunk transition, which is located at the present time just downstream of the so-called camp UpC. Reactivation of Kamb Ice Stream should be reflected in a downstream migration of the bulge-trunk transition at possibly high rates (bulge migration rates of ~km/yr occur on surging mountain glaciers). The modeling<br/>component will be used to generate predictions regarding the near-future behavior of Kamb Ice Stream. This project will provide training opportunities for at least two undergraduate students (per year) at St. Olaf College and for one<br/>undergraduate student (per year) at UCSC. This collaboration will bring together scientists from three different types of US institutions: (1) a liberal arts college (St.Olaf College), (2) a public research university (UCSC) and (3) a NASA research laboratory (JPL). The project will also help build a new glaciological research program at UCSC. Project results will be incorporated into undergraduate and graduate courses at UCSC and will be made available<br/>to the general public and educators through downloadable graphics and animations posted on the research website of the UCSC PI. Field data resulting from the project will be posted in the Antarctic Glaciological Data Center for use by other investigators.
This award supports a small grant for exploratory research to study the processes that contribute to the melting and break-up of tabular polar icebergs as they drift north. This work will enable the participation of a group of U.S. scientists in this international project which is collaborative with the Instituto Antartico Argentino. The field team will place weather instruments, firn sensors, and a video camera on the iceberg to measure the processes that affect it as it drifts north. In contrast to icebergs in other sectors of Antarctica, icebergs in the northwestern Weddell Sea drift northward along relatively predictable paths, and reach climate and ocean conditions that lead to break-up within a few years. The timing of this study is critical due to the anticipated presence of iceberg A43A, which broke off the Ronne Ice Shelf in February 2000 and which is expected to be accessible from Marambio Station in early 2006. It has recently been recognized that the end stages of break-up of these icebergs can imitate the rapid disintegrations due to melt ponding and surface fracturing observed for the Larsen A and Larsen B ice shelves. However, in some cases, basal melting may play a significant role in shelf break-up. Resolving the processes (surface ponding/ fracturing versus basal melt) and observing other processes of iceberg drift and break up in-situ are of high scientific interest. An understanding of the mechanisms that lead to the distintegration of icebergs as they drift north may enable scientists to use icebergs as proxies for understanding the processes that could cause ice shelves to disintegrate in a warming climate. A broader impact would thus be an ability to predict ice shelf disintegration in a warming world. Glacier mass balance and ice shelf stability are of critical importance to sea level change, which also has broader societal relevance.
9725882 Raymond This award is for support for a program of surface-based radio echo sounding to examine the geometry of the internal layering and the presence or absence of thawed zones outside the margins of active Ice Streams B and E and across the flow band feeding Ice Stream D. Melting in the marginal shear zone and/or on the bed outside an ice stream relates to the amount of support of the ice stream from the sides compared to the bed and the conditions that limit expansion of its width. Radar observations will be extended over the crest of adjacent inter-ice-stream ridges (B/C and D/E) and areas next to the flow band in the onset of D. The purpose is to examine internal layering indicative of the histories of these areas adjacent to ice streams and to determine whether ice streams have expanded into these presently stable areas in the past. These goals concerning the physical controls and history of ice stream width relate to how the discharge of ice streams has changed in the past and could change in the future to affect sea level.
This award supports a project to significantly improve our understanding of how Taylor Glacier flows and responds to climate changes. Taylor Glacier drains the Taylor Dome region of the East Antarctic Ice Sheet and terminates in Taylor Valley, one of the Dry Valleys of Victoria Land. It provides a crucial and unique link between two intensively studied Antarctic environments: the Taylor Dome, from which a 130 kyr ice core paleoclimate record has recently been extracted, and the Dry Valleys, a pivotal Long-Term Ecological Research (LTER) site and a focus of research on geomorphology and glacial geology. The proposed work will thus make an important contribution to ongoing efforts to exploit the Taylor Dome - Dry Valleys system to build a uniquely comprehensive view of regional long-term environmental changes. The proposed work has two complementary components: field research and numerical modelling. Two field seasons will be used to measure velocity, surface strain rate, mass balance, ice thickness, glacier bed reflectance, and subglacial topography, along a nearly complete longitudinal transect of the Taylor Glacier, and along select cross-valley transects. This information will be used to constrain numerical models of ice and heat flow for the Taylor Dome - Taylor Glacier system. These calibrated models will be used to analyze the time-dependent response of the Taylor Glacier to climate changes. The synthesis of results will be aimed to improve understanding of the glacial geomorphology of Taylor Valley, and to illuminate impacts on the Taylor Valley lakes ecosystem. The project will have a major role in furthering the careers of a doctoral-level graduate student and a post-doctoral researcher.