USAP-DC

{"dp_type": "Project", "free_text": "ice-flow model"}

[{"awards": "0087144 Conway, Howard", "bounds_geometry": "POLYGON((-150 -83.5,-148 -83.5,-146 -83.5,-144 -83.5,-142 -83.5,-140 -83.5,-138 -83.5,-136 -83.5,-134 -83.5,-132 -83.5,-130 -83.5,-130 -83.65,-130 -83.8,-130 -83.95,-130 -84.1,-130 -84.25,-130 -84.4,-130 -84.55,-130 -84.7,-130 -84.85,-130 -85,-132 -85,-134 -85,-136 -85,-138 -85,-140 -85,-142 -85,-144 -85,-146 -85,-148 -85,-150 -85,-150 -84.85,-150 -84.7,-150 -84.55,-150 -84.4,-150 -84.25,-150 -84.1,-150 -83.95,-150 -83.8,-150 -83.65,-150 -83.5))", "dataset_titles": "Impulse HF radar data from Conway Ridge", "datasets": [{"dataset_uid": "601810", "doi": "10.15784/601810", "keywords": "Antarctica; Cryosphere; Siple Coast", "people": "Hoffman, Andrew; Christianson, Knut; Conway, Howard", "repository": "USAP-DC", "science_program": null, "title": "Impulse HF radar data from Conway Ridge", "url": "https://www.usap-dc.org/view/dataset/601810"}], "date_created": "Mon, 22 Jul 2024 00:00:00 GMT", "description": "Marine ice sheets are low-pass filters of climate variability that take centuries to adjust to interior and near-terminus changes in mass balance. Constraining these century-scale changes from satellite observations that span only the last 40 years is challenging. Here, we take a different approach of carefully synthesizing different data sets to infer changes in the configurations of van der Veen and Mercer Ice Streams on the Siple Coast over the past 3000 years from englacial features encoded in ice-penetrating radar data. Englacial radar data from Conway Ridge reveal smooth, surface conformal layers overlying disrupted stratigraphy that suggest the van der Veen Ice Stream was 40 km wider over 3000 years ago. Englacial layer dating indicates that the ice stream narrowed to its present configuration between $\\sim3000$ and $\\sim1000$ years ago. Similarly disrupted stratigraphy and buried crevasses suggest that ice flowing from Mercer to Whillans Ice Stream across the northwestern tip of the ridge slowed shortly after. Using an ice-flow model capable of simulating shear margin migration, we evaluate whether small changes in ice thickness can lead to large changes in shear margin location. Our results suggest that the tip of Conway Ridge is sensitive to thinning and thickening, and that when the basal strength at the tip of the ridge increases with the height above flotation, the ice sheet shear margins can change quickly.", "east": -130.0, "geometry": "POINT(-140 -84.25)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIER ELEVATION/ICE SHEET ELEVATION; Siple Coast", "locations": "Siple Coast", "north": -83.5, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Hoffman, Andrew; Conway, Howard", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -85.0, "title": "Glacial History of Ridge AB, West Antarctica", "uid": "p0010470", "west": -150.0}, {"awards": "2152622 Morlighem, Mathieu", "bounds_geometry": "POLYGON((-110 -74,-109 -74,-108 -74,-107 -74,-106 -74,-105 -74,-104 -74,-103 -74,-102 -74,-101 -74,-100 -74,-100 -74.3,-100 -74.6,-100 -74.9,-100 -75.2,-100 -75.5,-100 -75.8,-100 -76.1,-100 -76.4,-100 -76.7,-100 -77,-101 -77,-102 -77,-103 -77,-104 -77,-105 -77,-106 -77,-107 -77,-108 -77,-109 -77,-110 -77,-110 -76.7,-110 -76.4,-110 -76.1,-110 -75.8,-110 -75.5,-110 -75.2,-110 -74.9,-110 -74.6,-110 -74.3,-110 -74))", "dataset_titles": "Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Data Underneath Thwaites Glacier, Antarctica", "datasets": [{"dataset_uid": "601658", "doi": "10.15784/601658", "keywords": "Airborne Radar; Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Thwaites; Thwaites Glacier", "people": "Das, Indrani", "repository": "USAP-DC", "science_program": "Thwaites (ITGC)", "title": "Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Data Underneath Thwaites Glacier, Antarctica", "url": "https://www.usap-dc.org/view/dataset/601658"}], "date_created": "Tue, 20 Dec 2022 00:00:00 GMT", "description": "This project contributes to the joint initiative launched by the U.S. National Science Foundation (NSF) and the U.K. Natural Environment Research Council (NERC) to substantially improve decadal and longer-term projections of ice loss and sea-level rise originating from Thwaites Glacier in West Antarctica. Thwaites Glacier has been accelerating and widening over the past three decades. How fast Thwaites will disintegrate or how quickly it will find a new stable state have become some of the most important questions of the future of the West Antarctic Ice Sheet and its contribution to sea-level rise over the next decades to centuries and beyond. This project will rely on three independent numerical models of ice flow, coupled to an ocean circulation model to (1) improve our understanding of the interactions between the ice and the underlying bedrock, (2) analyze how sensitive the glacier is to external changes, (3) assess the processes that may lead to a collapse of Thwaites, and, most importantly, (4) forecast future ice loss of Thwaites. By providing predictions based on a suite of coupled ice-ocean models, this project will also assess the uncertainty in model projections. The project will use three independent ice-sheet models: Ice Sheet System Model, Ua, and STREAMICE, coupled to the ocean circulation model of the MIT General Circulation Model. The team will first focus on the representation of key physical processes of calving, ice damage, and basal slipperiness that have either not been included, or are poorly represented, in previous ice-flow modelling work. The team will then quantify the relative role of different proposed external drivers of change (e.g., ocean-induced ice-shelf thinning, loss of ice-shelf pinning points) and explore the stability regime of Thwaites Glacier with the aim of identifying internal thresholds separating stable and unstable grounding-line retreat. Using inverse methodology, the project will produce new physically consistent high-resolution (300-m) data sets on ice-thicknesses from available radar measurements. Furthermore, the team will generate new remote sensing data sets on ice velocities and rates of elevation change. These will be used to constrain and validate the numerical models, and will also be valuable stand-alone data sets. This process will allow the numerical models to be constrained more tightly by data than has previously been possible. The resultant more robust model predictions of near-future impact of Thwaites Glacier on global sea levels can inform policy-relevant decision-making. 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": -100.0, "geometry": "POINT(-105 -75.5)", "instruments": null, "is_usap_dc": true, "keywords": "COMPUTERS; Amundsen Sea; ICE SHEETS", "locations": "Amundsen Sea", "north": -74.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": "NOT APPLICABLE", "persons": "Morlighem, Mathieu; Das, Indrani", "platforms": "OTHER \u003e MODELS \u003e COMPUTERS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.0, "title": "NSF-NERC: PROcesses, drivers, Predictions: Modeling the response of Thwaites Glacier over the next Century using Ice/Ocean Coupled Models (PROPHET)", "uid": "p0010400", "west": -110.0}, {"awards": "1542756 Koutnik, Michelle", "bounds_geometry": "POLYGON((-180 -77,-179.5 -77,-179 -77,-178.5 -77,-178 -77,-177.5 -77,-177 -77,-176.5 -77,-176 -77,-175.5 -77,-175 -77,-175 -77.9,-175 -78.8,-175 -79.7,-175 -80.6,-175 -81.5,-175 -82.4,-175 -83.3,-175 -84.2,-175 -85.1,-175 -86,-175.5 -86,-176 -86,-176.5 -86,-177 -86,-177.5 -86,-178 -86,-178.5 -86,-179 -86,-179.5 -86,180 -86,177.5 -86,175 -86,172.5 -86,170 -86,167.5 -86,165 -86,162.5 -86,160 -86,157.5 -86,155 -86,155 -85.1,155 -84.2,155 -83.3,155 -82.4,155 -81.5,155 -80.6,155 -79.7,155 -78.8,155 -77.9,155 -77,157.5 -77,160 -77,162.5 -77,165 -77,167.5 -77,170 -77,172.5 -77,175 -77,177.5 -77,-180 -77))", "dataset_titles": "Beardmore Glacier model in \u0027icepack\u0027", "datasets": [{"dataset_uid": "200339", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Beardmore Glacier model in \u0027icepack\u0027", "url": "https://github.com/danshapero/beardmore"}], "date_created": "Mon, 12 Dec 2022 00:00:00 GMT", "description": "Reconstructions of past changes in thickness and extent of the Antarctic ice sheet are important for evaluating past and present sea-level change, and for validating numerical models necessary to make realistic predictions of changes under future climate and ocean conditions. Models estimate that the Ross Sea sector was one of the largest contributors to sea-level rise from Antarctica as the ice sheet adjusted during the past ten thousand years from the glacial period to the Holocene. In this sector, ice flow into the embayment comes through West Antarctic ice streams and through East Antarctic outlet glaciers that flow through the Transantarctic Mountains. Observational data constrain the last glacial maximum and the Holocene retreat, but models are necessary to understand the environmental conditions needed for outlet glaciers to reach observed high stands, to fit the observed patterns of retreat, and to understand how the contribution of ice from West Antarctica and from East Antarctica changed over time. The investigators will use available geological and geophysical data in combination with forward ice-flow models and inverse models to investigate the evolution of the four Transantarctic outlet glaciers where sufficient data exist. The objectives of this new modeling are to constrain the glaciological conditions necessary for these glaciers to thicken during the last glacial, thin during the Holocene, and reach their present-day state. By testing specific hypotheses this work contributes to an interdisciplinary effort to understand Holocene deglaciation of the Ross Sea Embayment. In addition, the modeling will address the resolving power of the available data to answer key questions for each target glacier. Broader impacts include mentoring a graduate student, public outreach, incorporation of research into high-school and university classes, and support of an early-career investigator.", "east": -175.0, "geometry": "POINT(170 -81.5)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIERS; Transantarctic Mountains; GLACIER THICKNESS/ICE SHEET THICKNESS", "locations": "Transantarctic Mountains", "north": -77.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Koutnik, Michelle; Smith, Ben; Conway, Howard; Shapero, Daniel", "platforms": null, "repo": "GitHub", "repositories": "GitHub", "science_programs": null, "south": -86.0, "title": "Holocene Deglaciation of the Western Ross Embayment: Constraints from East Antarctic Outlet Glaciers", "uid": "p0010398", "west": 155.0}, {"awards": "1643961 Anandakrishnan, Sridhar", "bounds_geometry": "POLYGON((-80 -83,-79.8 -83,-79.6 -83,-79.4 -83,-79.2 -83,-79 -83,-78.8 -83,-78.6 -83,-78.4 -83,-78.2 -83,-78 -83,-78 -83.2,-78 -83.4,-78 -83.6,-78 -83.8,-78 -84,-78 -84.2,-78 -84.4,-78 -84.6,-78 -84.8,-78 -85,-78.2 -85,-78.4 -85,-78.6 -85,-78.8 -85,-79 -85,-79.2 -85,-79.4 -85,-79.6 -85,-79.8 -85,-80 -85,-80 -84.8,-80 -84.6,-80 -84.4,-80 -84.2,-80 -84,-80 -83.8,-80 -83.6,-80 -83.4,-80 -83.2,-80 -83))", "dataset_titles": "Rutford Ice Stream short period data", "datasets": [{"dataset_uid": "200336", "doi": "https://doi.org/10.7914/SN/5B_2018", "keywords": null, "people": null, "repository": "IRIS", "science_program": null, "title": "Rutford Ice Stream short period data", "url": "http://fdsn.adc1.iris.edu/networks/detail/5B_2018/"}], "date_created": "Wed, 16 Nov 2022 00:00:00 GMT", "description": "Anandakrishnan/1643961 This award supports a project to study conditions under the Rutford Ice Stream, a large glacier that flows from the interior of the West Antarctic Ice Sheet to the Filchner Ronne Ice Shelf and then on to the ocean. The speed and volume of ice delivered to the ocean by this and similar glaciers is central to the question of sea-level change in the coming decades: if the volume of ice carried by Rutford to the ocean increases, then it will contribute to a rise in sea level. Numerical models of glacier flow that are used to forecast future conditions must include a component that accounts for the sliding of the ice over its bed. The sliding process is poorly modeled because of lack of detailed information about the bottom of glaciers, leading to increased uncertainty in the ice-flow models. Data from this project will provide such information. During this project, in collaboration with researchers at the British Antarctic Survey, a detailed survey of the properties of the bed of Rutford Ice Stream will be carried out. These surveys include using seismic instruments (which are sensitive to naturally occurring earthquakes within glaciers--called icequakes) to monitor the distribution of those icequakes at the bed. The locations, size, and timing of icequakes are controlled by the properties of the bed such as porosity, water pressure, and stress. As part of this project, a hole will be drilled to the bed of the glacier to monitor water pressures and to extract a sample of the basal material. By comparing the pressure variations with icequake production, the properties of the basal material over a large area can be better determined. Those results will aid in the application of numerical models by informing their description of the sliding process. This award requires field work in Antarctica. 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": -78.0, "geometry": "POINT(-79 -84)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIERS/ICE SHEETS; Seismicity; Ice Dynamic; Rutford Ice Stream", "locations": "Rutford Ice Stream", "north": -83.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Anandakrishnan, Sridhar", "platforms": null, "repo": "IRIS", "repositories": "IRIS", "science_programs": null, "south": -85.0, "title": "Rutford Ice Stream Cooperative Research Program with British Antarctic Survey", "uid": "p0010392", "west": -80.0}, {"awards": "1744649 Christianson, Knut", "bounds_geometry": "POLYGON((-120 -85.5,-117.5 -85.5,-115 -85.5,-112.5 -85.5,-110 -85.5,-107.5 -85.5,-105 -85.5,-102.5 -85.5,-100 -85.5,-97.5 -85.5,-95 -85.5,-95 -85.62,-95 -85.74,-95 -85.86,-95 -85.98,-95 -86.1,-95 -86.22,-95 -86.34,-95 -86.46000000000001,-95 -86.58,-95 -86.7,-97.5 -86.7,-100 -86.7,-102.5 -86.7,-105 -86.7,-107.5 -86.7,-110 -86.7,-112.5 -86.7,-115 -86.7,-117.5 -86.7,-120 -86.7,-120 -86.58,-120 -86.46000000000001,-120 -86.34,-120 -86.22,-120 -86.1,-120 -85.98,-120 -85.86,-120 -85.74,-120 -85.62,-120 -85.5))", "dataset_titles": "Hercules Dome ApRES Data; Hercules Dome High-Frequency Impulse Ice-Penetrating Radar Data; Hercules Dome Ice-Penetrating Radar Swath Topographies; Ice Dynamics at the Intersection of the West and East Antarctic Ice Sheets; ITASE Impulse Radar Hercules Dome to South Pole", "datasets": [{"dataset_uid": "601739", "doi": "10.15784/601739", "keywords": "Antarctica; Apres; Crystal Orientation Fabric; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Hercules Dome; Ice Dynamic; Ice Penetrating Radar; Radar Interferometry; Radar Polarimetry", "people": "Christianson, Knut; Hills, Benjamin; Holschuh, Nicholas; Hoffman, Andrew; Fudge, Tyler J; Horlings, Annika; Erwin, Emma; Steig, Eric J.", "repository": "USAP-DC", "science_program": "Hercules Dome Ice Core", "title": "Hercules Dome ApRES Data", "url": "https://www.usap-dc.org/view/dataset/601739"}, {"dataset_uid": "601606", "doi": "10.15784/601606", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Ice Penetrating Radar; Snow/ice; Snow/Ice", "people": "Christianson, Knut", "repository": "USAP-DC", "science_program": null, "title": "Ice Dynamics at the Intersection of the West and East Antarctic Ice Sheets", "url": "https://www.usap-dc.org/view/dataset/601606"}, {"dataset_uid": "601710", "doi": "10.15784/601710", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Hercules Dome; Ice Penetrating Radar; Snow/ice; Snow/Ice", "people": "Hills, Benjamin; Hoffman, Andrew; Christianson, Knut; Christian, John; Holschuh, Nicholas; Horlings, Annika; O\u0027Connor, Gemma", "repository": "USAP-DC", "science_program": "Hercules Dome Ice Core", "title": "Hercules Dome High-Frequency Impulse Ice-Penetrating Radar Data", "url": "https://www.usap-dc.org/view/dataset/601710"}, {"dataset_uid": "601711", "doi": "10.15784/601711", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Hercules Dome; Ice Penetrating Radar; Snow/ice; Snow/Ice", "people": "Holschuh, Nicholas; Hoffman, Andrew; Christianson, Knut; Paden, John", "repository": "USAP-DC", "science_program": "Hercules Dome Ice Core", "title": "Hercules Dome Ice-Penetrating Radar Swath Topographies", "url": "https://www.usap-dc.org/view/dataset/601711"}, {"dataset_uid": "601712", "doi": "10.15784/601712", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Hercules Dome; Ice Penetrating Radar; Snow/ice; Snow/Ice", "people": "Welch, Brian; Jacobel, Robert; Christianson, Knut; Hoffman, Andrew", "repository": "USAP-DC", "science_program": "Hercules Dome Ice Core", "title": "ITASE Impulse Radar Hercules Dome to South Pole", "url": "https://www.usap-dc.org/view/dataset/601712"}], "date_created": "Tue, 02 Aug 2022 00:00:00 GMT", "description": "The response of the Antarctic ice sheet to climate change is a central issue in projecting global sea-level rise. While much attention is focused on the ongoing rapid changes at the coastal margin of the West Antarctic Ice Sheet, obtaining records of past ice-sheet and climate change is the only way to constrain how an ice sheet changes over millennial timescales. Whether the West Antarctic Ice Sheet collapsed during the last interglacial period (~130,000 to 116,000 years ago), when temperatures were slightly warmer than today, remains a major unsolved problem in Antarctic glaciology. Hercules Dome is an ice divide located at the intersection of the East Antarctic and West Antarctic ice sheets. It is ideally situated to record the glaciological and climatic effects of changes in the West Antarctic Ice Sheet. This project will establish whether Hercules Dome experienced major changes in flow due to changes in the elevation of the two ice sheets. The project will also ascertain whether Hercules Domes is a suitable site from which to recover climate records from the last interglacial period. These records could be used to determine whether the West Antarctic Ice Sheet collapsed during that period. The project will support two early-career researchers and train students at the University of Washington. Results will be communicated through outreach programs in coordination the Ice Drilling Project Office, the University of Washington\u0027s annual Polar Science Weekend in Seattle, and art-science collaboration. This project will develop a history of ice dynamics at the intersection of the East and West Antarctic ice sheets, and ascertain whether the site is suitable for a deep ice-coring operation. Ice divides provide a unique opportunity to assess the stability of past ice flow. The low deviatoric stresses and non-linearity of ice flow causes an arch (a \"Raymond Bump\") in the internal layers beneath a stable ice divide. This information can be used to determine the duration of steady ice flow. Due to the slow horizontal ice-flow velocities, ice divides also preserve old ice with internal layering that reflects past flow conditions caused by divide migration. Hercules Dome is an ice divide that is well positioned to retain information of past variations in the geometry of both the East and West Antarctic Ice Sheets. This dome is also the most promising location at which to recover an ice core that can be used to determine whether the West Antarctic Ice Sheet collapsed during the last interglacial period. Limited ice-penetrating radar data collected along a previous scientific surface traverse indicate well-preserved englacial stratigraphy and evidence suggestive of a Raymond Bump, but the previous survey was not sufficiently extensive to allow thorough characterization or determination of past changes in ice dynamics. This project will conduct a dedicated survey to map the englacial stratigraphy and subglacial topography as well as basal properties at Hercules Dome. The project will use ground-based ice-penetrating radar to 1) image internal layers and the ice-sheet basal interface, 2) accurately measure englacial attenuation, and 3) determine englacial vertical strain rates. The radar data will be combined with GPS observations for detailed topography and surface velocities and ice-flow modeling to constrain the basal characteristics and the history of past ice flow. 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": -95.0, "geometry": "POINT(-107.5 -86.1)", "instruments": null, "is_usap_dc": true, "keywords": "West Antarctica; ICE DEPTH/THICKNESS; East Antarctica", "locations": "West Antarctica; East Antarctica", "north": -85.5, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Christianson, Knut; Hoffman, Andrew; Holschuh, Nicholas", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -86.7, "title": "Ice Dynamics at the Intersection of the West and East Antarctic Ice Sheets", "uid": "p0010359", "west": -120.0}, {"awards": "1643285 Joughin, Ian; 1643174 Padman, Laurence", "bounds_geometry": "POLYGON((-104 -73,-102.2 -73,-100.4 -73,-98.6 -73,-96.8 -73,-95 -73,-93.2 -73,-91.4 -73,-89.6 -73,-87.8 -73,-86 -73,-86 -73.8,-86 -74.6,-86 -75.4,-86 -76.2,-86 -77,-86 -77.8,-86 -78.6,-86 -79.4,-86 -80.2,-86 -81,-87.8 -81,-89.6 -81,-91.4 -81,-93.2 -81,-95 -81,-96.8 -81,-98.6 -81,-100.4 -81,-102.2 -81,-104 -81,-104 -80.2,-104 -79.4,-104 -78.6,-104 -77.8,-104 -77,-104 -76.2,-104 -75.4,-104 -74.6,-104 -73.8,-104 -73))", "dataset_titles": "Beta Version of Plume Model; Data associated with Ice-Shelf Retreat Drives Recent Pine Island Glacier Speedup and Ocean-Induced Melt Volume Directly Paces Ice Loss from Pine Island Glacier; icepack; Pine Island Basin Scale Model", "datasets": [{"dataset_uid": "200290", "doi": "http://hdl.handle.net/1773/46687", "keywords": null, "people": null, "repository": "Uni. Washington ResearchWorks Archive", "science_program": null, "title": "Data associated with Ice-Shelf Retreat Drives Recent Pine Island Glacier Speedup and Ocean-Induced Melt Volume Directly Paces Ice Loss from Pine Island Glacier", "url": "https://doi.org/10.6069/2MZZ-6B61"}, {"dataset_uid": "200313", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Beta Version of Plume Model", "url": "https://github.com/icepack/plumes"}, {"dataset_uid": "200315", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Pine Island Basin Scale Model", "url": "https://github.com/fastice/icesheetModels"}, {"dataset_uid": "200314", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "icepack", "url": "https://github.com/icepack/icepack"}], "date_created": "Fri, 13 May 2022 00:00:00 GMT", "description": "The West Antarctic Ice Sheet contains enough ice to raise global sea levels by 3-4 meters. Ice-sheet volume falls, and sea level increases, when more ice is lost to the ocean by glacier flow than is replaced by snowfall. Glacier speed is reduced when ice shelves, which are the floating extensions of the ice sheets, are present. Processes that affect ice shelf thickness and extent therefore influence the rates of grounded ice loss and sea-level rise. West Antarctica is currently losing ice, at an accelerating rate, with most loss occurring in the Amundsen Sea region via discharge from Pine Island and Thwaites glaciers. This loss was initiated by increased circulation of relatively warm ocean water beneath these glacier\u0027s ice shelves, causing them to thin by melting. However, this melting also depends on how the changing shape of the ice shelves affects the ocean circulation beneath them and the speeds of the grounded glaciers upstream. Limited understanding of these processes leads to uncertainties in estimates of future ice loss. This interdisciplinary project brings together glaciologists and oceanographers from three US institutions to study the interactions between changing glacier flow, ice shelf shape and extent, and ocean circulation. Data and numerical models will be used to identify the key processes that determine how rapidly this region can shed ice. The project team will train postdocs and graduate students in cutting-edge modeling techniques, and educate the public about Antarctic ice loss through talks, school science fairs, and Seattle Science Center\u0027s annual Polar Science Weekend. The project team will conduct simulations, using a combination of ice-sheet and ocean models, to reduce uncertainties in projected ice loss from Pine Island and Thwaites glaciers by: (i) assessing how ice-shelf melt rates will change as the ice-shelf cavities evolve through melting and grounding-line retreat, and (ii) improving understanding of the sensitivity of sub-shelf melt rates to changes in ocean state on the nearby continental shelf. These studies will reduce uncertainty on ice loss and sea-level rise estimates, and lay the groundwork for development of future fully-coupled ice-sheet/ocean models. The project will first develop high-resolution ice-shelf-cavity circulation models driven by modern observed regional ocean state and validated with estimates of melt derived from satellite observations. Next, an ice-flow model will be used to estimate the future grounding retreat. An iterative process with the ocean-circulation and ice-flow models will then simulate melt rates at each stage of retreat. These results will help assess the validity of the hypothesis that unstable collapse of the Amundsen Sea sector of West Antarctica is underway, which was based on simplified models of melt rate. These models will also provide a better understanding of the sensitivity of melt to regional forcing such as changes in Circumpolar Deep Water temperature and wind-driven changes in thermocline height. Finally, several semi-coupled ice-ocean simulations will help determine the influence of the ocean-circulation driven melt over the next several decades. These simulations will provide a much-improved understanding of the linkages between far-field ocean forcing, cavity circulation and melting, and ice-sheet response.", "east": -86.0, "geometry": "POINT(-95 -77)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIER MOTION/ICE SHEET MOTION; USA/NSF; ICE SHEETS; AMD; USAP-DC; MODELS; Amd/Us; Pine Island Glacier", "locations": "Pine Island Glacier", "north": -73.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Ocean and Atmospheric Sciences; Antarctic Ocean and Atmospheric Sciences; Antarctic Integrated System Science; Antarctic Integrated System Science", "paleo_time": null, "persons": "Joughin, Ian; Dutrieux, Pierre; Padman, Laurence; Springer, Scott", "platforms": "OTHER \u003e MODELS \u003e MODELS", "repo": "Uni. Washington ResearchWorks Archive", "repositories": "GitHub; Uni. Washington ResearchWorks Archive", "science_programs": null, "south": -81.0, "title": "Collaborative Research: Modeling ice-ocean interaction for the rapidly evolving ice shelf cavities of Pine Island and Thwaites glaciers, Antarctica ", "uid": "p0010318", "west": -104.0}, {"awards": "1643394 Buizert, Christo", "bounds_geometry": "POLYGON((-180 -65,-144 -65,-108 -65,-72 -65,-36 -65,0 -65,36 -65,72 -65,108 -65,144 -65,180 -65,180 -67.5,180 -70,180 -72.5,180 -75,180 -77.5,180 -80,180 -82.5,180 -85,180 -87.5,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87.5,-180 -85,-180 -82.5,-180 -80,-180 -77.5,-180 -75,-180 -72.5,-180 -70,-180 -67.5,-180 -65))", "dataset_titles": "Antarctica 40,000 Year Temperature and Elevation Reconstructions; GISP2 and WAIS Divide Ice Cores 60,000 Year Surface Temperature Reconstructions; WAIS Divide 67-6ka nssS Data and EDML, EDC and TALDICE Volcanic Tie Points", "datasets": [{"dataset_uid": "200256", "doi": "", "keywords": null, "people": null, "repository": "NCEI", "science_program": null, "title": "WAIS Divide 67-6ka nssS Data and EDML, EDC and TALDICE Volcanic Tie Points", "url": "https://www.ncei.noaa.gov/access/paleo-search/study/24530"}, {"dataset_uid": "200255", "doi": "", "keywords": null, "people": null, "repository": "NCEI", "science_program": null, "title": "Antarctica 40,000 Year Temperature and Elevation Reconstructions", "url": "https://www.ncei.noaa.gov/access/paleo-search/study/32632"}, {"dataset_uid": "200257", "doi": "", "keywords": null, "people": null, "repository": "NCEI", "science_program": null, "title": "GISP2 and WAIS Divide Ice Cores 60,000 Year Surface Temperature Reconstructions", "url": "https://www.ncei.noaa.gov/access/paleo-search/study/34133"}], "date_created": "Wed, 10 Nov 2021 00:00:00 GMT", "description": "Buizert/1643394 This award supports a project to use ice cores to study teleconnections between the northern hemisphere, tropics, and Antarctica during very abrupt climate events that occurred during the last ice age (from 70,000 to 11,000 years ago). The observations can be used to test scientific theories about the role of the westerly winds on atmospheric carbon dioxide. In a warming world, snow fall in Antarctica is expected to increase, which can reduce the Antarctic contribution to sea level rise, all else being equal. The study will investigate how snow fall changed in the past in response to changes in temperature and atmospheric circulation, which can help improve projections of future sea level rise. Antarctica is important for the future evolution of our planet in several ways; it has the largest inventory of land-based ice, equivalent to about 58 m of global sea level and currently contributes about 0.3 mm per year to global sea level rise, which is expected to increase in the future due to global warming. The oceans surrounding Antarctica help regulate the uptake of human-produced carbon dioxide. Shifts in the position and strength of the southern hemisphere westerly winds could change the amount of carbon dioxide that is absorbed by the ocean, which will influence the rate of global warming. The climate and winds near and over Antarctica are linked to the rest of our planet via so-called climatic teleconnections. This means that climate changes in remote places can influence the climate of Antarctica. Understanding how these climatic teleconnections work in both the ocean and atmosphere is an important goal of climate research. The funds will further contribute towards training of a postdoctoral researcher and an early-career researcher; outreach to public schools; and the communication of research findings to the general public via the media, local events, and a series of Wikipedia articles. The project will help to fully characterize the timing and spatial pattern of millennial-scale Antarctic climate change during the deglaciation and Dansgaard-Oeschger (DO) cycles using multiple synchronized Antarctic ice cores. The phasing of Antarctic climate change relative to Greenland DO events can distinguish between fast atmospheric teleconnections on sub-decadal timescales, and slow oceanic ones on centennial time scales. Preliminary work suggests that the spatial pattern of Antarctic change can fingerprint specific changes to the atmospheric circulation; in particular, the proposed work will clarify past movements of the Southern Hemisphere westerly winds during the DO cycle, which have been hypothesized. The project will help resolve a discrepancy between two previous seminal studies on the precise timing of interhemispheric coupling between ice cores in both hemispheres. The study will further provide state-of-the-art, internally-consistent ice core chronologies for all US Antarctic ice cores, as well as stratigraphic ties that can be used to integrate them into a next-generation Antarctic-wide ice core chronological framework. Combined with ice-flow modeling, these chronologies will be used for a continent-wide study of the relationship between ice sheet accumulation and temperature during the last deglaciation.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "ISOTOPES; Antarctica; USA/NSF; AMD; ICE CORE RECORDS; USAP-DC; VOLCANIC DEPOSITS; MODELS; Amd/Us", "locations": "Antarctica", "north": -65.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Buizert, Christo; Wettstein, Justin", "platforms": "OTHER \u003e MODELS \u003e MODELS", "repo": "NCEI", "repositories": "NCEI", "science_programs": null, "south": -90.0, "title": "Collaborative Research: The Timing and Spatial Expression of the Bipolar Seesaw in Antarctica from Synchronized Ice Cores", "uid": "p0010279", "west": -180.0}, {"awards": "1643355 Steig, Eric; 1643394 Buizert, Christo", "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": "Antarctica 40,000 Year Temperature and Elevation Reconstructions; Layer and Thinning based Accumulation Rate Reconstructions; WAIS Divide 67-6ka nssS Data and EDML, EDC and TALDICE Volcanic Tie Points", "datasets": [{"dataset_uid": "601448", "doi": "10.15784/601448", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Snow/ice; Snow/Ice", "people": "Fudge, T. J.", "repository": "USAP-DC", "science_program": null, "title": "Layer and Thinning based Accumulation Rate Reconstructions", "url": "https://www.usap-dc.org/view/dataset/601448"}, {"dataset_uid": "200219", "doi": "", "keywords": null, "people": null, "repository": "NCEI", "science_program": null, "title": "Antarctica 40,000 Year Temperature and Elevation Reconstructions", "url": "https://www.ncdc.noaa.gov/paleo-search/study/32632"}, {"dataset_uid": "200220", "doi": "", "keywords": null, "people": null, "repository": "NCEI", "science_program": null, "title": "WAIS Divide 67-6ka nssS Data and EDML, EDC and TALDICE Volcanic Tie Points", "url": "https://www.ncdc.noaa.gov/paleo/study/24530"}], "date_created": "Fri, 28 May 2021 00:00:00 GMT", "description": "Buizert/1643394 This award supports a project to use ice cores to study teleconnections between the northern hemisphere, tropics, and Antarctica during very abrupt climate events that occurred during the last ice age (from 70,000 to 11,000 years ago). The observations can be used to test scientific theories about the role of the westerly winds on atmospheric carbon dioxide. In a warming world, snow fall in Antarctica is expected to increase, which can reduce the Antarctic contribution to sea level rise, all else being equal. The study will investigate how snow fall changed in the past in response to changes in temperature and atmospheric circulation, which can help improve projections of future sea level rise. Antarctica is important for the future evolution of our planet in several ways; it has the largest inventory of land-based ice, equivalent to about 58 m of global sea level and currently contributes about 0.3 mm per year to global sea level rise, which is expected to increase in the future due to global warming. The oceans surrounding Antarctica help regulate the uptake of human-produced carbon dioxide. Shifts in the position and strength of the southern hemisphere westerly winds could change the amount of carbon dioxide that is absorbed by the ocean, which will influence the rate of global warming. The climate and winds near and over Antarctica are linked to the rest of our planet via so-called climatic teleconnections. This means that climate changes in remote places can influence the climate of Antarctica. Understanding how these climatic teleconnections work in both the ocean and atmosphere is an important goal of climate research. The funds will further contribute towards training of a postdoctoral researcher and an early-career researcher; outreach to public schools; and the communication of research findings to the general public via the media, local events, and a series of Wikipedia articles. The project will help to fully characterize the timing and spatial pattern of millennial-scale Antarctic climate change during the deglaciation and Dansgaard-Oeschger (DO) cycles using multiple synchronized Antarctic ice cores. The phasing of Antarctic climate change relative to Greenland DO events can distinguish between fast atmospheric teleconnections on sub-decadal timescales, and slow oceanic ones on centennial time scales. Preliminary work suggests that the spatial pattern of Antarctic change can fingerprint specific changes to the atmospheric circulation; in particular, the proposed work will clarify past movements of the Southern Hemisphere westerly winds during the DO cycle, which have been hypothesized. The project will help resolve a discrepancy between two previous seminal studies on the precise timing of interhemispheric coupling between ice cores in both hemispheres. The study will further provide state-of-the-art, internally-consistent ice core chronologies for all US Antarctic ice cores, as well as stratigraphic ties that can be used to integrate them into a next-generation Antarctic-wide ice core chronological framework. Combined with ice-flow modeling, these chronologies will be used for a continent-wide study of the relationship between ice sheet accumulation and temperature during the last deglaciation.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIERS/ICE SHEETS; Antarctica", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Fudge, T. J.; Steig, Eric J.; Buizert, Christo", "platforms": null, "repo": "USAP-DC", "repositories": "NCEI; USAP-DC", "science_programs": null, "south": -90.0, "title": "Collaborative Research: The Timing and Spatial Expression of the Bipolar Seesaw", "uid": "p0010183", "west": -180.0}, {"awards": "0838783 Conway, Howard; 0838256 Todd, Claire; 0838784 Balco, Gregory", "bounds_geometry": "POLYGON((-66.27517 -83.23921,-65.341961 -83.23921,-64.408752 -83.23921,-63.475543 -83.23921,-62.542334 -83.23921,-61.609125 -83.23921,-60.675916 -83.23921,-59.742707 -83.23921,-58.809498 -83.23921,-57.876289 -83.23921,-56.94308 -83.23921,-56.94308 -83.359865,-56.94308 -83.48052,-56.94308 -83.601175,-56.94308 -83.72183,-56.94308 -83.842485,-56.94308 -83.96314,-56.94308 -84.083795,-56.94308 -84.20445,-56.94308 -84.325105,-56.94308 -84.44576,-57.876289 -84.44576,-58.809498 -84.44576,-59.742707 -84.44576,-60.675916 -84.44576,-61.609125 -84.44576,-62.542334 -84.44576,-63.475543 -84.44576,-64.408752 -84.44576,-65.341961 -84.44576,-66.27517 -84.44576,-66.27517 -84.325105,-66.27517 -84.20445,-66.27517 -84.083795,-66.27517 -83.96314,-66.27517 -83.842485,-66.27517 -83.72183,-66.27517 -83.601175,-66.27517 -83.48052,-66.27517 -83.359865,-66.27517 -83.23921))", "dataset_titles": "Interface to observational data collected in this project and geologic age information derived therefrom. Dynamic content, continuously updated.; Web page linking to documents containing data collected in this project. Static content", "datasets": [{"dataset_uid": "200195", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Web page linking to documents containing data collected in this project. Static content", "url": "http://noblegas.berkeley.edu/~balcs/pensacola/"}, {"dataset_uid": "200194", "doi": "", "keywords": null, "people": null, "repository": "ICE-D", "science_program": null, "title": "Interface to observational data collected in this project and geologic age information derived therefrom. Dynamic content, continuously updated.", "url": "https://version2.ice-d.org/antarctica/nsf/"}], "date_created": "Sat, 19 Dec 2020 00:00:00 GMT", "description": "This award supports a project to find and date geologic evidence of past ice-marginal positions in the Pensacola Mountains, which border the Foundation Ice Stream at the head of the Weddell Sea embayment. The project will involve glacial geologic mapping and cosmogenic-nuclide surface exposure dating of glacially transported erratics. An ice-flow model will be used to link our exposure-dating results together in a glaciologically consistent way, and to relate them to regional LGM to Holocene elevation changes. A secondary focus of the project seeks to improve the effectiveness of exposure-dating methods in understanding ice sheet change. Changes in the location of the ice margin, and thus the exposure ages that record these changes, are controlled not only by regional ice sheet mass balance, but also by local effects on snow- and icefields immediately adjacent to the exposure-dating sites. This part of the project will combine glaciological observations near the present ice margin with targeted exposure- age sampling in an effort to better understand the processes controlling the ice margin location, and improve the interpretation of very recent exposure-age data as a record of latest Holocene to present ice sheet changes. The intellectual merit of the project is that it will provide direct geologic evidence of LGM-to-Holocene ice volume change in a region of Antarctica where no such evidence now exists. The broader impacts of the work involve both gathering information needed for accurate understanding of past and present global sea level change. Secondly, this project will help to develop and maintain the human and intellectual resources necessary for continued excellence in polar research and global change education, by linking experienced Antarctic researchers with early career scientists who seek to develop their expertise in both research and education. In addition, it brings together two early career scientists whose careers are focused at opposite ends of the research-education spectrum, thus facilitating better integration of research and education both in the careers of these scientists and in the outcome of this project. This award has field work in Antarctica.", "east": -56.94308, "geometry": "POINT(-61.609125 -83.842485)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIERS/ICE SHEETS; GLACIER THICKNESS/ICE SHEET THICKNESS; NOT APPLICABLE; GLACIER ELEVATION/ICE SHEET ELEVATION; Antarctica", "locations": "Antarctica", "north": -83.23921, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Glaciology", "paleo_time": "PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY \u003e HOLOCENE; PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY \u003e PLEISTOCENE", "persons": "Balco, Gregory; Todd, Claire; Conway, Howard", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "PI website", "repositories": "ICE-D; PI website", "science_programs": null, "south": -84.44576, "title": "Collaborative Research: Last Glacial Maximum and Deglaciation Chronology for the Foundation Ice Stream and Southeastern Weddell Sea Embayment", "uid": "p0010151", "west": -66.27517}, {"awards": "1246045 Waddington, Edwin", "bounds_geometry": "POLYGON((-180 -70,-144 -70,-108 -70,-72 -70,-36 -70,0 -70,36 -70,72 -70,108 -70,144 -70,180 -70,180 -72,180 -74,180 -76,180 -78,180 -80,180 -82,180 -84,180 -86,180 -88,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -88,-180 -86,-180 -84,-180 -82,-180 -80,-180 -78,-180 -76,-180 -74,-180 -72,-180 -70))", "dataset_titles": "Code for inference of fabric from sonic velocity and thin-section measurements.; Code for models involving stochastic treatment of ice fabric", "datasets": [{"dataset_uid": "000244", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Code for models involving stochastic treatment of ice fabric", "url": "https://github.com/mjhay/stochastic_fabric"}, {"dataset_uid": "000243", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Code for inference of fabric from sonic velocity and thin-section measurements.", "url": "https://github.com/mjhay/neem_sonic_model"}], "date_created": "Mon, 02 Apr 2018 00:00:00 GMT", "description": "Waddington/1246045 This award supports a project to investigate the onset and growth of folds and other disturbances seen in the stratigraphic layers of polar ice sheets. The intellectual merit of the work is that it will lead to a better understanding of the grain-scale processes that control the development of these stratigraphic features in the ice and will help answer questions such as what processes can initiate such disturbances. Snow is deposited on polar ice sheets in layers that are generally flat, with thicknesses that vary slowly along the layers. However, ice cores and ice-penetrating radar show that in some cases, after conversion to ice, and following lengthy burial, the layers can become folded, develop pinch-and-swell structures (boudinage), and be sheared by ice flow, at scales ranging from centimeters to hundreds of meters. The processes causing these disturbances are still poorly understood. Disturbances appear to develop first at the ice-crystal scale, then cascade up to larger scales with continuing ice flow and strain. Crystal-scale processes causing distortions of cm-scale layers will be modeled using Elle, a microstructure-modeling package, and constrained by fabric thin-sections and grain-elongation measurements from the West Antarctic Ice Sheet divide ice-core. A full-stress continuum anisotropic ice-flow model coupled to an ice-fabric evolution model will be used to study bulk flow of anisotropic ice, to understand evolution and growth of flow disturbances on the meter and larger scale. Results from this study will assist in future ice-core site selection, and interpretation of stratigraphy in ice cores and radar, and will provide improved descriptions of rheology and stratigraphy for ice-sheet flow models.The broader impacts are that it will bring greater understanding to ice dynamics responsible for stratigraphic disturbance. This information is valuable to constrain depth-age relationships in ice cores for paleoclimate study. This will allow researchers to put current climate change in a more accurate context. This project will provide three years of support for a graduate student as well as support and research experience for an undergraduate research assistant; this will contribute to development of talent needed to address important future questions in glaciology and climate change. The research will be communicated to the public through outreach events and results from the study will be disseminated through public and professional meetings as well as journal publications. The project does not require field work in Antarctica.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "NOT APPLICABLE; USAP-DC", "locations": null, "north": -70.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Waddington, Edwin D.", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "GitHub", "repositories": "GitHub", "science_programs": null, "south": -90.0, "title": "Anisotropic Ice and Stratigraphic Disturbances", "uid": "p0000073", "west": -180.0}, {"awards": "0944191 Taylor, Kendrick; 0944197 Waddington, Edwin", "bounds_geometry": "POLYGON((-180 -79,-173.3 -79,-166.6 -79,-159.9 -79,-153.2 -79,-146.5 -79,-139.8 -79,-133.1 -79,-126.4 -79,-119.7 -79,-113 -79,-113 -79.1,-113 -79.2,-113 -79.3,-113 -79.4,-113 -79.5,-113 -79.6,-113 -79.7,-113 -79.8,-113 -79.9,-113 -80,-119.7 -80,-126.4 -80,-133.1 -80,-139.8 -80,-146.5 -80,-153.2 -80,-159.9 -80,-166.6 -80,-173.3 -80,180 -80,150.9 -80,121.8 -80,92.7 -80,63.6 -80,34.5 -80,5.4 -80,-23.7 -80,-52.8 -80,-81.9 -80,-111 -80,-111 -79.9,-111 -79.8,-111 -79.7,-111 -79.6,-111 -79.5,-111 -79.4,-111 -79.3,-111 -79.2,-111 -79.1,-111 -79,-81.9 -79,-52.8 -79,-23.7 -79,5.4 -79,34.5 -79,63.6 -79,92.7 -79,121.8 -79,150.9 -79,-180 -79))", "dataset_titles": "Accumulation Rates from the WAIS Divide Ice Core; WAIS Divide Ice Core Electrical Conductance Measurements, Antarctica; WAIS Divide Multi Track Electrical Measurements; WD2014: Timescale for WAIS Divide Core 2006 A (WDC-06A)", "datasets": [{"dataset_uid": "601004", "doi": "10.15784/601004", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Snow Accumulation; WAIS Divide Ice Core", "people": "Waddington, Edwin D.; Buizert, Christo; Conway, Howard; Fudge, T. J.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Accumulation Rates from the WAIS Divide Ice Core", "url": "https://www.usap-dc.org/view/dataset/601004"}, {"dataset_uid": "601172", "doi": "10.15784/601172", "keywords": "Antarctic; Antarctica; Electrical Conductivity; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice; Ice Core Data; Ice Core Records; Physical Properties; Snow/ice; Snow/Ice; WAIS Divide; WAIS Divide Ice Core; Wais Project; West Antarctic Ice Sheet", "people": "Taylor, Kendrick C.; Fudge, T. J.", "repository": "USAP-DC", "science_program": null, "title": "WAIS Divide Multi Track Electrical Measurements", "url": "https://www.usap-dc.org/view/dataset/601172"}, {"dataset_uid": "609591", "doi": "10.7265/N5B56GPJ", "keywords": "Antarctica; Electrical Conductivity; Glaciers/ice Sheet; Glaciers/Ice Sheet; Ice Core Records; Physical Properties; WAIS Divide; WAIS Divide Ice Core", "people": "Fudge, T. J.; Taylor, Kendrick C.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "WAIS Divide Ice Core Electrical Conductance Measurements, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609591"}, {"dataset_uid": "601015", "doi": "10.15784/601015", "keywords": "Antarctica; Depth-Age-Model; Geochronology; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; WAIS Divide; WAIS Divide Ice Core", "people": "Fudge, T. J.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "WD2014: Timescale for WAIS Divide Core 2006 A (WDC-06A)", "url": "https://www.usap-dc.org/view/dataset/601015"}], "date_created": "Tue, 25 Apr 2017 00:00:00 GMT", "description": "This award supports a project to help to establish the depth-age chronology and the histories of accumulation and ice dynamics for the WAIS Divide ice core. The depth-age relationship and the histories of accumulation and ice dynamics are coupled. An accurate age scale is needed to infer histories of accumulation rate and ice-thickness change using ice-flow models. In turn, the accumulation-rate history is needed to calculate the age difference of ice to determine the age of the trapped gases. The accumulation history is also needed to calculate atmospheric concentrations of impurities trapped in the ice and is an important characteristic of climate. The history of ice-thickness change is also fundamental to understanding the stability of the WAIS. The primary goals of the WAIS Divide ice core project are to investigate climate forcing by greenhouse gases, the initiation of climate changes, and the stability of the West Antarctic Ice Sheet (WAIS). An accurate age scale is fundamental for achieving these goals. The first objective of this project is to establish an annually resolved depth-age relationship for the past 40,000 years. This will be done by measuring variations in electrical conductivity along the ice core, which are caused by seasonal variations in chemistry. We expect to be able to resolve annual layers back to 40,000 years before present (3,000 m depth) using this method. The second objective is to search for stratigraphic disturbances in the core that would compromise the paleoclimate record. Irregular layering will be identified by measuring the electrical conductivity of the ice in a vertical plan through the core. The third objective is to derive a preliminary chronology for the entire core. For the deeper ice we will use an ice-flow model to interpolate between known age markers, such as dated volcanic horizons and tie points from the methane gas chronology. The fourth objective is to derive a refined chronology simultaneously with histories of accumulation and ice-sheet thickness. An ice-flow model and all available data will be used to formulate an inverse problem, in which we infer the most appropriate histories of accumulation and ice-thickness, together with estimates of uncertainties. The flow model associated with those preferred histories then produces the best estimate of the chronology. The research contributes directly to the primary goals of the West Antarctic Ice Sheet Initiative. The project will help develop the next generation of scientists through the education and training of one Ph.D. student and several undergraduate students. This project will result in instrumentation for measuring the electrical conductivity of ice cores being available at the National Ice Core Lab for other researchers to use on other projects. All collaborators are committed to fostering diversity and currently participate in scientific outreach and most participate in undergraduate education. Outreach will be accomplished through regularly scheduled community and K-12 outreach events at UW, talks and popular writing by the PIs, as well as through our respective press offices.", "east": -111.0, "geometry": "POINT(-112 -79.5)", "instruments": null, "is_usap_dc": true, "keywords": "Ice Core Depth; National Ice Core Lab; Electrical Conductivity; FIELD INVESTIGATION; Not provided", "locations": null, "north": -79.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Glaciology; Antarctic Glaciology; Antarctic Earth Sciences", "paleo_time": null, "persons": "Conway, Howard; Fudge, T. J.; Taylor, Kendrick C.; Waddington, Edwin D.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -80.0, "title": "Collaborative Research: Establishing the Chronology and Histories of Accumulation and Ice Dynamics for the WAIS Divide Core", "uid": "p0000026", "west": -113.0}, {"awards": "0537752 Creyts, Timothy; 0538674 Winebrenner, Dale", "bounds_geometry": null, "dataset_titles": "Millennially Averaged Accumulation Rates for Lake Vostok; Modeled Radar Attenuation Rate Profile at the Vostok 5G Ice Core Site, Antarctica", "datasets": [{"dataset_uid": "609501", "doi": "10.7265/N59K485D", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Lake Vostok; Radar Attenuation Rate; Vostok Ice Core", "people": "Matsuoka, Kenichi; Studinger, Michael S.; Macgregor, Joseph A.", "repository": "USAP-DC", "science_program": null, "title": "Modeled Radar Attenuation Rate Profile at the Vostok 5G Ice Core Site, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609501"}, {"dataset_uid": "609500", "doi": "10.7265/N5F769HV", "keywords": "Accumulation Rate; Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Lake Vostok", "people": "Studinger, Michael S.; Winebrenner, Dale; Waddington, Edwin D.; Macgregor, Joseph A.; Matsuoka, Kenichi", "repository": "USAP-DC", "science_program": null, "title": "Millennially Averaged Accumulation Rates for Lake Vostok", "url": "https://www.usap-dc.org/view/dataset/609500"}], "date_created": "Thu, 09 Aug 2012 00:00:00 GMT", "description": "0538674\u003cbr/\u003eMatsuoka\u003cbr/\u003eThis award supports a project to evaluate radio-echo intensities in the available SOAR ice-penetrating radar data along grids covering Lake Vostok, and along four regional tracks from Ridge B toward the lake. The project has two objectives; first, it will examine the upper surface of the lake and reflectors hypothesized to be a boundary between the meteoric and accreted ice. They will provide crucial knowledge on the dynamic evolution of the lake. Second, this project will examine a poorly understood echo-free zone within the deep ice in central East Antarctica. This zone may consist of distorted stagnant ice, while its upper boundary may be a shear zone. The SOAR radar data provide a unique resource to examine spatiotemporal water circulation patterns that should be understood in order to select the best direct-sampling strategy to the lake. The Vostok ice core provides a unique opportunity to do this work. First, the path effects, i.e. propagation loss and birefringence, will be derived at the ice-core site using ice temperature, chemistry, and fabric data. Second, lateral variations of the propagation loss will be estimated by tracking chemistry associated with radar-detected isochronous layers, and by inferring temperatures from an ice-flow model that can replicate those layers. Ice-fabric patterns will be inferred from anisotropy in the reflectivity at about 100 radar-track cross-over sites. In terms of broader impacts, a graduate student will be trained to interpret the radar data in the light of radar theory and glaciological context of Lake Vostok and summer workshops for K-12 teachers will be provided in Seattle and New York. This project will contribute to ongoing efforts to study Lake Vostok and will complement the site selection for a North Vostok ice core, which has been proposed by Russia and France as an IPY program.", "east": null, "geometry": null, "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; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e LIDAR/LASER SOUNDERS \u003e LASERS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e ALTIMETERS \u003e RADAR ALTIMETERS \u003e ALTIMETERS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e ALTIMETERS \u003e RADAR ALTIMETERS \u003e RADAR ALTIMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e CHEMICAL METERS/ANALYZERS \u003e ION CHROMATOGRAPHS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e THERMOMETERS \u003e THERMOMETERS", "is_usap_dc": true, "keywords": "Airborne Radar Sounding; DHC-6; Salinity; Lake Vostok; Antarctic Ice Sheet; Modeling; FIELD SURVEYS; Model Output; Accumulation Rate; MODELS; Numerical Model; Ice Sheet; Not provided; Hydrostatic; Aerogeophysical; Subglacial; Attenuation Rate; Radar; FIELD INVESTIGATION; Model; Circulation; LABORATORY", "locations": "Lake Vostok; Antarctic Ice Sheet", "north": null, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": "PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY \u003e HOLOCENE; PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY \u003e PLEISTOCENE", "persons": "Matsuoka, Kenichi; Winebrenner, Dale; Creyts, Timothy; Macgregor, Joseph A.; Studinger, Michael S.; Waddington, Edwin D.", "platforms": "AIR-BASED PLATFORMS \u003e PROPELLER \u003e DHC-6; 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; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Collaborative Research: Deciphering the Deep Ice and the Ice-water Interface over Lake Vostok Using Existing Radar Data", "uid": "p0000090", "west": null}, {"awards": "0636997 Waddington, Edwin", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Tue, 20 Mar 2012 00:00:00 GMT", "description": "Waddington/0636997\u003cbr/\u003e\u003cbr/\u003eThis award supports a project to integrate three lines of glaciology research, previously treated independently. First, internal layers in ice sheets, detected by ice-penetrating radar, retain information about past spatial and temporal patterns of ice accumulation. Ice-flow modelers can recover this information, using geophysical inverse methods; however, the ages of the layers must be known, through interpolation where they intersect a well-dated ice core. \u003cbr/\u003eSecond, concentrations of methane and some other atmospheric constituents vary through time as climate changes. However, the atmosphere is always well mixed, and concentrations are similar world-wide at any one time, so gas variations from an undated core can be correlated with those in a well-dated core such as GISP2. Because air in near-surface firn mixes readily with the atmosphere above, the air that is trapped in bubbles deep in the firn is typically hundreds to thousands of years younger than that firn. Gas geochemists must calculate this age difference, called delta-age, with a firn-densification model before the ice enclosing the gas can be dated accurately. To calculate delta-age, they must know the temperature and the snow accumulation rate at the time and place where the snow fell. Third, gases can be correlated between cores only at times when the atmosphere changed, so ice-core dates must be interpolated at depths between the sparse dated points. Simplistic interpolation schemes can create undesirable artifacts in the depth-age profile. The intellectual merit of this project is that it will develop new interpolation methods that calculate layer thinning over time due to ice-flow mechanics. Accurate interpolation also requires a spatial and temporal accumulation history. These three issues are coupled through accumulation patterns and ice-core dates. This project will develop an integrated inversion procedure to solve all three problems simultaneously. The new method will incorporate ice-penetrating radar profile data and ice-core data, and will find self-consistent: spatial/temporal accumulation patterns; delta-age profiles for ice cores; and reliably interpolated depth-age profiles. The project will then: recalculate the depth-age profile at Byrd Station, Antarctica; provide a preliminary depth-age at the West Antarctic Ice Sheet (WAIS) in the initial stages of drilling, using radar layers with estimated ages traced from Byrd Station; and generate a self-consistent depth-age relationship for Taylor Dome, Antarctica over the past 20ka, where low accumulation has created uncertainty in dating, accumulation, and controversy over delta-age estimates. The broader impacts of the project are that it will support the PhD research of a female graduate student, and her continued outreach work with Making Connections, a non-profit program through the University of Washington Women\u0027s Center, which matches professional women mentors with minority high-school women interested in mathematics and science, disciplines where they are traditionally under-represented. The graduate student will also work with Girls on Ice, a ten-day glacier field program, taught by women scientist instructors, emphasizing scientific observation through immersion, leadership skills and safety awareness.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "Internal Layers; LABORATORY; Ice Core; FIELD SURVEYS; Firn; FIELD INVESTIGATION; Accumulation; Glaciology; Climate Change; Ice Sheet", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Carns, Regina; Hay, Mike; Waddington, Edwin D.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repositories": null, "science_programs": null, "south": null, "title": "Self-consistent Ice Dynamics, Accumulation, Delta-age, and Interpolation of Sparse Age Data using an Inverse Approach", "uid": "p0000376", "west": null}, {"awards": "0636996 Waddington, Edwin; 0940650 Pettit, Erin", "bounds_geometry": "POLYGON((-165 -75,-159 -75,-153 -75,-147 -75,-141 -75,-135 -75,-129 -75,-123 -75,-117 -75,-111 -75,-105 -75,-105 -76,-105 -77,-105 -78,-105 -79,-105 -80,-105 -81,-105 -82,-105 -83,-105 -84,-105 -85,-111 -85,-117 -85,-123 -85,-129 -85,-135 -85,-141 -85,-147 -85,-153 -85,-159 -85,-165 -85,-165 -84,-165 -83,-165 -82,-165 -81,-165 -80,-165 -79,-165 -78,-165 -77,-165 -76,-165 -75))", "dataset_titles": null, "datasets": null, "date_created": "Fri, 16 Mar 2012 00:00:00 GMT", "description": "Pettit/0636795\u003cbr/\u003e\u003cbr/\u003eThis award supports a project to constrain the accumulation rate, thickness, and temperature history for Siple Dome using a vertical velocity profile that includes the effects of an evolving fabric on deformation through time, to invert the depth-profile of fabric determined from sonic velocity measurements and grain size observed in thin sections in Siple Dome for the surface temperature and accumulation rate changes in the past, focusing on the apparent abrupt climate change events at 22ka and 15ka. The intellectual merit of the work is that it will extract past climate information from a number of physical properties of the deep ice using a coupled fabric evolution and ice-sheet flow model. The focus will be on the deep ice-age ice at Siple Dome, where the ice-core record shows puzzling signals and where modeling results imply intriguing deformation patterns. The method will also be applied to the records from Byrd Station and Taylor Dome to ultimately form a basis for future analysis of the West Antarctic Divide core. The broader impacts of the project are that it will ultimately contribute to our understanding of the effects of anisotropy on ice flow dynamics in West Antarctica. It will contribute to our understanding of the connection between ice flow and the paleoclimate record in ice cores, particularly with respect to the relationship between the chemical record and ice deformation. And it will contribute a new ice-flow model that includes the effects of anisotropy and fabric evolution. The project will also contribute to advancing the career of a new, young, female investigator and will support a couple of graduate students. Finally, the work will encouraging diversity in the physical sciences by directly helping to support the Girls on Ice a program that encourages young women to explore science and the natural world.", "east": -105.0, "geometry": "POINT(-135 -80)", "instruments": null, "is_usap_dc": false, "keywords": "LABORATORY; FIELD SURVEYS; FIELD INVESTIGATION; Vertical Velocity; COMPUTERS; Ice Core; Firn; Accumulation Rate; Siple Dome; Ice Thickness; Abrupt Climate Change; Ice Temperature; Metamorphism; Anisotropy; Antarctica", "locations": "Siple Dome; Antarctica", "north": -75.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Pettit, Erin; Waddington, Edwin D.", "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", "repositories": null, "science_programs": null, "south": -85.0, "title": "Collaborative Research: Anisotropy, Abrupt Climate Change, and the Deep Ice in West Antarctica", "uid": "p0000741", "west": -165.0}, {"awards": "0636818 Stone, John", "bounds_geometry": "POLYGON((-157 -85,-156 -85,-155 -85,-154 -85,-153 -85,-152 -85,-151 -85,-150 -85,-149 -85,-148 -85,-147 -85,-147 -85.3,-147 -85.6,-147 -85.9,-147 -86.2,-147 -86.5,-147 -86.8,-147 -87.1,-147 -87.4,-147 -87.7,-147 -88,-148 -88,-149 -88,-150 -88,-151 -88,-152 -88,-153 -88,-154 -88,-155 -88,-156 -88,-157 -88,-157 -87.7,-157 -87.4,-157 -87.1,-157 -86.8,-157 -86.5,-157 -86.2,-157 -85.9,-157 -85.6,-157 -85.3,-157 -85))", "dataset_titles": null, "datasets": null, "date_created": "Fri, 05 Aug 2011 00:00:00 GMT", "description": "Hall/0636687\u003cbr/\u003e\u003cbr/\u003eThis award supports a project to investigate late Pleistocene and Holocene changes in Scott Glacier, a key outlet glacier that flows directly into the Ross Sea just west of the present-day West Antarctic Ice Sheet (WAIS) grounding line. The overarching goals are to understand changes in WAIS configuration in the Ross Sea sector at and since the last glacial maximum (LGM) and to determine whether Holocene retreat observed in the Ross Embayment has ended or if it is still ongoing. To address these goals, moraine and drift sequences associated with Scott Glacier will be mapped and dated and ice thickness, surface velocity and surface mass balance will be measured to constrain an ice-flow model of the glacier. This model will be used to help interpret the dated geologic sequences. The intellectual merit of the project relates to gaining a better understanding of the West Antarctic Ice Sheet and how changing activity of fast-flowing outlet glaciers and ice streams exerts strong control on the mass balance of the ice sheet. Previous work suggests that grounding-line retreat in the Ross Sea continued into the late Holocene and left open the possibility of ongoing deglaciation as part of a long-term trend. Results from Reedy Glacier, an outlet glacier just behind the grounding line, suggest that retreat may have slowed substantially over the past 2000 years and perhaps even stopped. By coupling the work on Scott Glacier with recent data from Reedy Glacier, the grounding-line position will be bracketed and it should be possible to establish whether the retreat has truly ended or if it is ongoing. The broader impacts of the work relate to the societal relevance of an improved understanding of the West Antarctic ice sheet to establish how it will respond to current and possible future environmental changes. The work addresses this key goal of the West Antarctic Ice Sheet Initiative, as well as the International Polar Year focus on ice sheet history and dynamics. The work will develop future scientists through the education and training of one undergraduate and two Ph.D. students, interaction with K-12 students through classroom visits, web-based \u0027expedition\u0027 journals, letters from the field, and discussions with teachers. Results from this project will be posted with previous exposure dating results from Antarctica, on the University of Washington Cosmogenic Nuclide Lab website, which also provides information about chemical procedures and calculation methods to other scientists working with cosmogenic nuclides.", "east": -147.0, "geometry": "POINT(-152 -86.5)", "instruments": null, "is_usap_dc": false, "keywords": "Not provided", "locations": null, "north": -85.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Stone, John; Conway, Howard", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": -88.0, "title": "Collaborative Research:Grounding-line Retreat in the Southern Ross Sea - Constraints from Scott Glacier", "uid": "p0000149", "west": -157.0}, {"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": "0440670 Hulbe, Christina; 0440636 Fahnestock, Mark", "bounds_geometry": "POLYGON((-180 -70,-175 -70,-170 -70,-165 -70,-160 -70,-155 -70,-150 -70,-145 -70,-140 -70,-135 -70,-130 -70,-130 -71.6,-130 -73.2,-130 -74.8,-130 -76.4,-130 -78,-130 -79.6,-130 -81.2,-130 -82.8,-130 -84.4,-130 -86,-135 -86,-140 -86,-145 -86,-150 -86,-155 -86,-160 -86,-165 -86,-170 -86,-175 -86,180 -86,180 -86,180 -86,180 -86,180 -86,180 -86,180 -86,180 -86,180 -86,180 -86,180 -86,180 -84.4,180 -82.8,180 -81.2,180 -79.6,180 -78,180 -76.4,180 -74.8,180 -73.2,180 -71.6,180 -70,180 -70,180 -70,180 -70,180 -70,180 -70,180 -70,180 -70,180 -70,180 -70,-180 -70))", "dataset_titles": "MOA-derived Structural Feature Map of the Ronne Ice Shelf; MOA-derived Structural Feature Map of the Ross Ice Shelf; Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams", "datasets": [{"dataset_uid": "600024", "doi": "", "keywords": null, "people": "Fahnestock, Mark", "repository": "USAP-DC", "science_program": null, "title": "Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams", "url": "https://www.usap-dc.org/view/dataset/600024"}, {"dataset_uid": "609497", "doi": "10.7265/N5PR7SXR", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; MOA; MODIS; Ronne Ice Shelf", "people": "Hulbe, Christina; Ledoux, Christine", "repository": "USAP-DC", "science_program": null, "title": "MOA-derived Structural Feature Map of the Ronne Ice Shelf", "url": "https://www.usap-dc.org/view/dataset/609497"}, {"dataset_uid": "601432", "doi": "10.15784/601432", "keywords": "Antarctica", "people": "Forbes, Martin; Ledoux, Christine; Hulbe, Christina", "repository": "USAP-DC", "science_program": null, "title": "MOA-derived Structural Feature Map of the Ross Ice Shelf", "url": "https://www.usap-dc.org/view/dataset/601432"}], "date_created": "Thu, 25 Sep 2008 00:00:00 GMT", "description": "This award supports a three year project to develop the tools required to interpret complex patterns of flow features on the Ross Ice Shelf, which record the discharge history the ice streams flowing east off of the West Antarctic Ice Sheet. This work builds on previous research that used flow features visible in satellite image mosaics and numerical models of ice shelf flow to detect changes in grounding zone dynamics and redirection of ice stream outlets over hundreds of years. Recently observed changes on Whillans Ice Stream fit within this framework. The pattern of redirection is driven by the influence of rapid downstream thinning on the basal thermal gradient in the ice and associated \"sticky spot\" (ice rise) formation. In pursuing this work, the investigators recognized other records of discharge variation on the shelf that can be used to build a more complete history and understanding of ice-stream discharge variability. The intellectual merit of the proposed work lies in the fact that these records, including fracture patterns and spatial variation in ice thickness, when understood in the proper context, will yield quantitative information about the timing and dynamics of ice stream slowdowns, grounding line retreat, and the relative history of discharge between the ice streams. New tools will help further constrain this history. The laser altimeter on NASA\u0027s IceSAT has improved our knowledge of the surface elevation of Antarctic ice. IceSAT surface elevations provide a high-resolution map of ice-shelf thickness that, along with provenance maps from ice-shelf image mosaics, will be used to estimate the volumes of ice involved in past ice-stream discharge events (slowdowns, redirections, and so on). This project will develop new numerical models for fracture propagation; these will allow past variations in ice-shelf stress state to be investigated. Together, the dynamic and volume-flux histories will provide a powerful set of observations for understanding past variations in ice stream discharge and the underlying physical processes. The broader impacts of this project center on how it contributes to the ability to estimate West Antarctic contributions to global sea level rise and to answer outstanding questions about the causes of millennial and longer-scale evolution of ice streams. This work will provide a history of the most complex record of ice discharge known. In addition to the incorporation of this research into graduate student advising and normal teaching duties, the investigators are involved in other avenues of civic engagement and education. Outreach to high school students and the community at large is promoted on an annual basis by the investigators at both institutions. New outreach projects at Portland State University are developed with the assistance of researchers with expertise in student learning and achievement in science and mathematics. The collaborative research team includes two glaciologists with experience in the pairing of high resolution satellite imagery and a variety of ice-flow models and a geologist whose focus is the mechanics of rock deformation.", "east": -130.0, "geometry": "POINT(-155 -78)", "instruments": "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 SPECTROMETERS/RADIOMETERS \u003e IMAGING SPECTROMETERS/RADIOMETERS \u003e MODIS", "is_usap_dc": true, "keywords": "FIELD INVESTIGATION; Fracture Patterns; Ross Ice Shelf; West Antarctic Ice Sheet; Not provided; Antarctica; TERRA; Ice Sheet; Ice Rise; LABORATORY; Ice-Stream Discharge; West Antarctica; Fracture Propagation; SATELLITES; Ice Stream Motion; Grounding Line; Ice Movement; Ice Stream; Whillans Ice Stream; Ice Stream Outlets; Basal Temperature Gradient; Numerical Model; Ice Thickness; Flow Features; Kamb Ice Stream; Antarctic Ice Sheet; Satellite Image Mosaics; Icesat; Grounding Line Migration; ICESAT", "locations": "Kamb Ice Stream; Whillans Ice Stream; Antarctica; Ross Ice Shelf; West Antarctic Ice Sheet; Antarctic Ice Sheet; West Antarctica", "north": -70.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Hulbe, Christina; Ledoux, Christine; Fahnestock, Mark", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; Not provided; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e ICE, CLOUD AND LAND ELEVATION SATELLITE (ICESAT) \u003e ICESAT; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e SATELLITES; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e TERRA", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -86.0, "title": "Collaborative Research: Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams", "uid": "p0000096", "west": 180.0}]

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