USAP-DC

{"dp_type": "Project", "free_text": "bubbles"}

[{"awards": "2218402 Fegyveresi, John", "bounds_geometry": "POLYGON((-115 -85.5,-113.5 -85.5,-112 -85.5,-110.5 -85.5,-109 -85.5,-107.5 -85.5,-106 -85.5,-104.5 -85.5,-103 -85.5,-101.5 -85.5,-100 -85.5,-100 -85.65,-100 -85.8,-100 -85.95,-100 -86.1,-100 -86.25,-100 -86.4,-100 -86.55,-100 -86.7,-100 -86.85,-100 -87,-101.5 -87,-103 -87,-104.5 -87,-106 -87,-107.5 -87,-109 -87,-110.5 -87,-112 -87,-113.5 -87,-115 -87,-115 -86.85,-115 -86.7,-115 -86.55,-115 -86.4,-115 -86.25,-115 -86.1,-115 -85.95,-115 -85.8,-115 -85.65,-115 -85.5))", "dataset_titles": null, "datasets": null, "date_created": "Mon, 19 Sep 2022 00:00:00 GMT", "description": "Brittle ice has been a long-standing and consistent challenge for ice-coring projects, complicating sampling, and introducing the possibility of contamination. Several procedures have been tested to reduce brittle damage to recovered cores, but many come with high monetary and time costs. Our background research suggests that bubble size and c-axis fabric are primary drivers for brittleness and are predictable from site characteristics, enabling prediction of brittleness before coring. We propose to improve understanding of the mechanisms involved in brittle ice onset and behavior, through targeted investigations of various ice physical properties, in carefully selected samples across multiple ice-core sites, in order to guide the upcoming Hercules Dome ice-core drilling and science communities. This project will involve collaboration between Northern Arizona University, the National Science Foundation Ice Core Facility, and Pennsylvania State University, and will utilize new and existing ice-core physical properties data from several previously drilled sites. This is a high-risk, low-cost project that could yield important results, and thus is well-suited for EAGER funding. This proposal utilizes existing ice cores and does not require Antarctic fieldwork. ", "east": -100.0, "geometry": "POINT(-107.5 -86.25)", "instruments": null, "is_usap_dc": true, "keywords": "Hercules Dome Ice Core; bubbles; grain statistics; ICE SHEETS; West Antarctica; LABORATORY; ice cores; c-axis fabric; brittle ice; physical properties; ICE CORE RECORDS", "locations": "West Antarctica", "north": -85.5, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Fegyveresi, John", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repositories": null, "science_programs": "Hercules Dome Ice Core", "south": -87.0, "title": "EAGER: Constraining the Expected Brittle-ice Behavior for the Hercules Dome Ice-core Site.", "uid": "p0010378", "west": -115.0}, {"awards": "1643669 Petrenko, Vasilii; 1643716 Buizert, Christo; 1643664 Severinghaus, Jeffrey", "bounds_geometry": "POLYGON((112 -66,112.2 -66,112.4 -66,112.6 -66,112.8 -66,113 -66,113.2 -66,113.4 -66,113.6 -66,113.8 -66,114 -66,114 -66.1,114 -66.2,114 -66.3,114 -66.4,114 -66.5,114 -66.6,114 -66.7,114 -66.8,114 -66.9,114 -67,113.8 -67,113.6 -67,113.4 -67,113.2 -67,113 -67,112.8 -67,112.6 -67,112.4 -67,112.2 -67,112 -67,112 -66.9,112 -66.8,112 -66.7,112 -66.6,112 -66.5,112 -66.4,112 -66.3,112 -66.2,112 -66.1,112 -66))", "dataset_titles": "Concentration and isotopic composition of atmospheric N2O over the last century; Law Dome DE08-OH firn air 15N, O2/N2, Ar/N2, 18O of O2; Law Dome DE08-OH site noble gases in ice: testing the 86Krexcess proxy", "datasets": [{"dataset_uid": "601597", "doi": "10.15784/601597", "keywords": "Antarctica; Cryosphere; ice cores; Law Dome; noble gases", "people": "Severinghaus, Jeffrey P.", "repository": "USAP-DC", "science_program": null, "title": "Law Dome DE08-OH site noble gases in ice: testing the 86Krexcess proxy", "url": "https://www.usap-dc.org/view/dataset/601597"}, {"dataset_uid": "601598", "doi": "10.15784/601598", "keywords": "Antarctica; Cryosphere; Firn; firn densification; Gravitational Settling; Inert Gases; Law Dome", "people": "Severinghaus, Jeffrey P.", "repository": "USAP-DC", "science_program": null, "title": "Law Dome DE08-OH firn air 15N, O2/N2, Ar/N2, 18O of O2", "url": "https://www.usap-dc.org/view/dataset/601598"}, {"dataset_uid": "601693", "doi": "10.15784/601693", "keywords": "Antarctic; Antarctica; Anthropogenic Emission; Atmosphere; Cryosphere; Cryosphere; Greenhouse Gas; Greenland; Ice Core Data; Nitrification and Denitrification Processes; Nitrous Oxide; Site-specific 15N isotopomer; Styx Glacier", "people": "Yoshida, Naohiro ; Langenfelds, Ray L ; Joong Kim, Seong; Etheridge, David; Buizert, Christo ; Toyoda, Sakae ; Ghosh, Sambit; Ahn, Jinho ", "repository": "USAP-DC", "science_program": null, "title": "Concentration and isotopic composition of atmospheric N2O over the last century", "url": "https://www.usap-dc.org/view/dataset/601693"}], "date_created": "Fri, 17 Jun 2022 00:00:00 GMT", "description": "Hydroxyl radicals are responsible for removal of most atmospheric trace gases, including pollutants and important greenhouse gases. They have been called the \"detergent of the atmosphere\". Changes in hydroxyl radical concentration in response to large changes in reactive trace gas emissions, which may happen in the future, are uncertain. This project aims to provide the first estimates of the variability of atmospheric hydroxyl radicals since about 1880 AD when anthropogenic emissions of reactive trace gases were minimal. This will improve understanding of their stability in response to large changes in emissions. The project will also investigate whether ice cores record past changes in Southern Hemisphere westerly winds. These winds are a key component of the global climate system, and have an important influence on ocean circulation and possibly on atmospheric carbon dioxide concentrations. The project team will include three early career scientists, a postdoctoral researcher, and graduate and undergraduate students, working in collaboration with senior scientists and Australian collaborators. \u003cbr/\u003e \u003cbr/\u003eFirn air and shallow ice to a depth of about 233 m will be sampled at the Law Dome high-accumulation coastal site in East Antarctica. Trapped air will be extracted from the ice cores on site immediately after drilling. Carbon-14 of carbon monoxide (14CO) will be analyzed in firn and ice-core air samples. Corrections will be made for the in situ cosmogenic 14CO component in the ice, allowing for the atmospheric 14CO history to be reconstructed. This 14CO history will be interpreted with the aid of a chemistry-transport model to place the first observational constraints on the variability of Southern Hemisphere hydroxyl radical concentration after about 1880 AD. An additional component of the project will analyze Krypton-86 in the firn-air and ice-core samples. These measurements will explore whether ice-core Krypton-86 acts as a proxy for barometric pressure variability, and whether this proxy can be used in Antarctic ice cores to infer past movement of the Southern Hemisphere westerly winds.\u003cbr/\u003e\u003cbr/\u003eThis 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": 114.0, "geometry": "POINT(113 -66.5)", "instruments": null, "is_usap_dc": true, "keywords": "LABORATORY; AMD; TRACE GASES/TRACE SPECIES; Law Dome; USAP-DC; ICE CORE AIR BUBBLES; AMD/US; USA/NSF", "locations": "Law Dome", "north": -66.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Petrenko, Vasilii; Murray, Lee T; Buizert, Christo; Petrenko, Vasilii; Murray, Lee T", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -67.0, "title": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability", "uid": "p0010341", "west": 112.0}, {"awards": "1445205 Putkonen, Jaakko", "bounds_geometry": "POLYGON((157.6 -83.2,157.62 -83.2,157.64 -83.2,157.66 -83.2,157.68 -83.2,157.7 -83.2,157.72 -83.2,157.74 -83.2,157.76 -83.2,157.78 -83.2,157.8 -83.2,157.8 -83.21,157.8 -83.22,157.8 -83.23,157.8 -83.24,157.8 -83.25,157.8 -83.26,157.8 -83.27,157.8 -83.28,157.8 -83.29,157.8 -83.3,157.78 -83.3,157.76 -83.3,157.74 -83.3,157.72 -83.3,157.7 -83.3,157.68 -83.3,157.66 -83.3,157.64 -83.3,157.62 -83.3,157.6 -83.3,157.6 -83.29,157.6 -83.28,157.6 -83.27,157.6 -83.26,157.6 -83.25,157.6 -83.24,157.6 -83.23,157.6 -83.22,157.6 -83.21,157.6 -83.2))", "dataset_titles": "Cosmogenic-Nuclide data at ICE-D; Old Ice, Ong Valley, Transantarctic Mountains", "datasets": [{"dataset_uid": "200295", "doi": "", "keywords": null, "people": null, "repository": "ICE-D", "science_program": null, "title": "Cosmogenic-Nuclide data at ICE-D", "url": "https://version2.ice-d.org/antarctica/nsf/"}, {"dataset_uid": "601665", "doi": "10.15784/601665", "keywords": "Antarctica; Buried Ice; Cosmogenic Isotopes; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Old Ice; Ong Valley", "people": "Putkonen, Jaakko; Bergelin, Marie", "repository": "USAP-DC", "science_program": null, "title": "Old Ice, Ong Valley, Transantarctic Mountains", "url": "https://www.usap-dc.org/view/dataset/601665"}], "date_created": "Fri, 16 Jul 2021 00:00:00 GMT", "description": "Finding the oldest ice on Earth can tell us about the climate and life forms in the distant past\r\n\r\nRecently we discovered a mile wide and hundreds of feet thick ice body in Antarctica that is buried under just a few feet of dirt. Thus far our analyses of the dirt suggest that the ice is over million years old. Generally, glacial ice contains tiny bubbles and dirt that was deposited and locked in the ice by the ancient snowfall and today still holds small samples of the atmospheric gases and everything else that was carried by the winds in the past. Such samples may include the amount of greenhouse gases, plant pollen, microbes, and mineral dust. Therefore the glaciers are like archives where we can access and study the Earth\u2019s history with samples that are unavailable anywhere else. Ice survives poorly on Earth\u2019s surface and therefore currently only few ice samples are known that are approximately million years old. Our site has a high potential to harbor perhaps the oldest ice on Earth. However, first we need to sample and date the ice. Our research will also help us understand how these pockets of buried ice can survive such unusually long periods of time. Such understanding will help us study the landforms and history of not only Antarctica but also the Mars where similar dirt covered glaciers are found today.\r\n\r\nWe propose to collect regolith samples through the approximately 1 m thick cover and to core the buried ice in Ong Valley down to 10 m depth to determine the cosmogenic nuclide concentrations both in the regolith and in the embedded mineral matter suspended in the ice. The systematics of the target cosmogenic nuclides (10Be, 26Al, and 21Ne) such as half-lives, isotope production rates, production pathways, and related attenuation lengths allow us to uniquely determine the age of the ice and the rate the ice is sublimating. Our existing samples and analyses reveal accumulation of mineral matter at the base of surficial debris layer and the surface erosion of this debris by eolian processes. The intellectual merit of the proposed activity: Our main objective is to unequivocally determine the age and sublimation rate of two buried massive ice bodies in time scale of thousands to millions of years. The slow sublimation is a fundamentally Antarctic process, and may have altered most of the currently ice-free areas throughout the continent. Similar large, debris covered ice bodies have been recently discovered in Mars as well. Our results may transform the understanding of the longevity of the buried ice bodies and potentially reveal the oldest ice ever found in the interior of the Antarctica. If proven old and slowly sublimating, this buried ice can potentially yield direct information about the atmospheric chemistry, ancient life forms, and geology of greater antiquity than the currently available and sampled ice bodies. The broader impacts resulting from the proposed activity: The results will be relevant to researchers in glaciology, paleoclimatology, planetary geology, and biology. Several students will participate in the project and do field work in Antarctica, work in lab, attend meetings, attend outreach activities, and produce videos. A graduate student will prepare his/her thesis on a topic closely related to the objectives of the proposed research. The results of the research will be published in scientific meetings and publications.\r\n", "east": 157.8, "geometry": "POINT(157.7 -83.25)", "instruments": null, "is_usap_dc": true, "keywords": "USAP-DC; AMD; USA/NSF; FIELD SURVEYS; Transantarctic Mountains; AMD/US; GLACIERS/ICE SHEETS", "locations": "Transantarctic Mountains", "north": -83.2, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Glaciology", "paleo_time": null, "persons": "putkonen, jaakko; Balco, Gregory; Morgan, Daniel", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS", "repo": "ICE-D", "repositories": "Other; USAP-DC", "science_programs": null, "south": -83.3, "title": "Collaborative Research: Long Term Sublimation/Preservation of Two Separate, Buried Glacier Ice Masses, Ong Valley, Southern Transantarctic Mountains", "uid": "p0010231", "west": 157.6}, {"awards": "1935438 McCarthy, Christine", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Thu, 03 Jun 2021 00:00:00 GMT", "description": "The ice sheets of Antarctica and Greenland are losing mass and contributing to accelerating global sea-level rise. Satellite altimetry provides precise measurement of ice-sheet volume change, but computing ice-sheet mass change the quantity relevant for estimating the ice sheets sea-level contribution requires knowing the density of the ice sheet. The density near the ice-sheet surface also affects age estimates of air bubbles recovered in ice cores, which are a key source of information on past climate changes. Ice-sheet density is primarily controlled by the rate at which firn (snow that has persisted for a year or more on ice sheets) compacts into ice, but there is currently no widely accepted theory of how this compaction occurs. The goal of this project is thus to advance understanding of how firn densifies. The team will conduct laboratory experiments and analyze ice-penetrating radar and ice-core data from Antarctica. A key desired outcome of the project is a new model of firn densification that can be used to improve satellite-based altimetry measurements of present-day ice-sheet change and reconstructions of past climate changes from ice cores.\r\n\r\nThis project will combine laboratory experiments, numerical modeling, and geophysical techniques to determine the rheology of firn as it compacts to form ice. The team will use two methods to measure firn compaction: (1) lab-based experiments and (2) analysis of ice-core and radar data. For the lab-based work, the team will conduct a suite of compaction experiments on synthetic firn samples under uni-axial strain and constant temperature and axial stress. They will also measure the grain-size evolution. By running a large number of experiments (\u003e 25), the team will constrain key parameters that determine how firn compaction rate depends on density, temperature, grain size, and axial stress. The experiments will be conducted in a table-top apparatus at temperatures as low as -40 degrees C and axial stresses up to 4 MPa. For the field-data-based component, the team will analyze ice-core and ice-penetrating radar data to produce the first coincident set of radar-derived firn compaction rates, borehole temperatures, firn densities, and firn grain sizes. Results from lab and field data will be tied together using a numerical firn compaction model. This model is formulated using conservation of mass, momentum, and energy, along with an explicit description of firn rheology and grain-size evolution. Constraints on firn rheology will be incorporated into this model and the team will use it to examine fundamental questions about how changes in the climate affect firn density. This is a crucial unknown that contributes significant measurement uncertainty in estimates of past and present climate change.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "AMD; LABORATORY; USA/NSF; COMPUTERS; AMD/US; USAP-DC; FIRN; Antarctic Ice Sheet", "locations": "Antarctic Ice Sheet", "north": null, "nsf_funding_programs": "Antarctic Glaciology; Arctic Natural Sciences", "paleo_time": null, "persons": "McCarthy, Christine M.; Kingslake, Jonathan", "platforms": "OTHER \u003e MODELS \u003e COMPUTERS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repositories": null, "science_programs": null, "south": null, "title": "Understanding Firn Rheology Through Laboratory Compaction Experiments and Radar Data", "uid": "p0010185", "west": null}, {"awards": "1419979 Severinghaus, Jeffrey", "bounds_geometry": "POLYGON((166.65 -78.62,166.654 -78.62,166.658 -78.62,166.662 -78.62,166.666 -78.62,166.67 -78.62,166.674 -78.62,166.678 -78.62,166.682 -78.62,166.686 -78.62,166.69 -78.62,166.69 -78.6205,166.69 -78.621,166.69 -78.6215,166.69 -78.622,166.69 -78.6225,166.69 -78.623,166.69 -78.6235,166.69 -78.624,166.69 -78.6245,166.69 -78.625,166.686 -78.625,166.682 -78.625,166.678 -78.625,166.674 -78.625,166.67 -78.625,166.666 -78.625,166.662 -78.625,166.658 -78.625,166.654 -78.625,166.65 -78.625,166.65 -78.6245,166.65 -78.624,166.65 -78.6235,166.65 -78.623,166.65 -78.6225,166.65 -78.622,166.65 -78.6215,166.65 -78.621,166.65 -78.6205,166.65 -78.62))", "dataset_titles": null, "datasets": null, "date_created": "Mon, 18 May 2020 00:00:00 GMT", "description": "The PIs have designed and built a new type of rapid access ice drill (RAID) for use in Antarctica. This community tool has the ability to rapidly drill through ice up to 3300 m thick and then collect samples of the ice, ice-sheet bed interface, and bedrock substrate below. This drilling technology will provide a new way to obtain in situ measurements and samples for interdisciplinary studies in geology, glaciology, paleoclimatology, microbiology, and astrophysics. The RAID drilling platform will give the scientific community access to records of geologic and climatic change on a variety of timescales, from the billion-year rock record to million-year ice and climate histories. Development of this platform will enable scientists to address critical questions about the deep interface between the Antarctic ice sheets and the substrate below. Phase I was for design and work with the research community to develop detailed science requirements for the drill. This proposal, Phase II, constructed, assembled and tested the RAID drilling platform at a site near McMurdo (Minna Bluff) where 700-m thick ice sits on bedrock.", "east": 166.69, "geometry": "POINT(166.67 -78.6225)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES", "is_usap_dc": true, "keywords": "FIELD INVESTIGATION; WAIS Divide Ice Cores; USAP-DC; ICE CORE AIR BUBBLES; Minna Bluff", "locations": "Minna Bluff", "north": -78.62, "nsf_funding_programs": "Antarctic Instrumentation and Support", "paleo_time": null, "persons": "Severinghaus, Jeffrey P.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repositories": null, "science_programs": null, "south": -78.625, "title": "Collaborative Research: Phase 2 Development of A Rapid Access Ice Drilling (RAID) Platform for Research in Antarctica", "uid": "p0010099", "west": 166.65}, {"awards": "1644013 Gaetani, Glenn; 1644027 Wallace, Paul; 1644020 Sims, Kenneth W.", "bounds_geometry": "POLYGON((164.1 -77.1,164.65 -77.1,165.2 -77.1,165.75 -77.1,166.3 -77.1,166.85 -77.1,167.4 -77.1,167.95 -77.1,168.5 -77.1,169.05 -77.1,169.6 -77.1,169.6 -77.235,169.6 -77.37,169.6 -77.505,169.6 -77.64,169.6 -77.775,169.6 -77.91,169.6 -78.045,169.6 -78.18,169.6 -78.315,169.6 -78.45,169.05 -78.45,168.5 -78.45,167.95 -78.45,167.4 -78.45,166.85 -78.45,166.3 -78.45,165.75 -78.45,165.2 -78.45,164.65 -78.45,164.1 -78.45,164.1 -78.315,164.1 -78.18,164.1 -78.045,164.1 -77.91,164.1 -77.775,164.1 -77.64,164.1 -77.505,164.1 -77.37,164.1 -77.235,164.1 -77.1))", "dataset_titles": "G170 Electron Microprobe Analyses of Melt Inclusions and Host Olivines; G170 Raman Spectroscopy \u0026 Tomography Volumes of Melt Inclusions and Vapor Bubbles; G170 Sample Locations Ross Island \u0026 Discovery Province; G170 Secondary Ion Mass Spectrometry Analses of Melt Inclusion Volatiles; G170 Secondary Ion Mass Spectrometry Analyses of Melt Inclusion Hydrogen Isotopes; Location and Description of Tephra Samples from the Erebus and Discovery Sub-provinces", "datasets": [{"dataset_uid": "601250", "doi": "10.15784/601250", "keywords": "Antarctica; Hut Point Peninsula; Mt. Bird; Mt. Morning; Mt. Terror; Ross Island; Turks Head; Turtle Rock", "people": "Gaetani, Glenn; Pamukcu, Ayla", "repository": "USAP-DC", "science_program": null, "title": "Location and Description of Tephra Samples from the Erebus and Discovery Sub-provinces", "url": "https://www.usap-dc.org/view/dataset/601250"}, {"dataset_uid": "601504", "doi": "10.15784/601504", "keywords": "Antarctica; Cryosphere; Ross Island; Sample/Collection Description; Sample Location", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Sample Locations Ross Island \u0026 Discovery Province", "url": "https://www.usap-dc.org/view/dataset/601504"}, {"dataset_uid": "601505", "doi": "10.15784/601505", "keywords": "Antarctica; Chemistry:Rock; Cryosphere; Electron Microprobe Analyses; Olivine; Petrography; Ross Island", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Electron Microprobe Analyses of Melt Inclusions and Host Olivines", "url": "https://www.usap-dc.org/view/dataset/601505"}, {"dataset_uid": "601506", "doi": "10.15784/601506", "keywords": "Antarctica; Cryosphere; Ion Mass Spectrometry; Ross Island; Volatiles", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Secondary Ion Mass Spectrometry Analses of Melt Inclusion Volatiles", "url": "https://www.usap-dc.org/view/dataset/601506"}, {"dataset_uid": "601507", "doi": "10.15784/601507", "keywords": "Antarctica; Chemistry:Rock; Cryosphere; Geochemistry; Hydrogen; Ion Mass Spectrometry; Ross Island", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Secondary Ion Mass Spectrometry Analyses of Melt Inclusion Hydrogen Isotopes", "url": "https://www.usap-dc.org/view/dataset/601507"}, {"dataset_uid": "601508", "doi": "10.15784/601508", "keywords": "Antarctica; Chemistry:Rock; Cryosphere; Geochemistry; Melt Inclusions; Raman Spectroscopy; Ross Island; Vapor Bubbles; Volcanic", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Raman Spectroscopy \u0026 Tomography Volumes of Melt Inclusions and Vapor Bubbles", "url": "https://www.usap-dc.org/view/dataset/601508"}], "date_created": "Sat, 08 Feb 2020 00:00:00 GMT", "description": "The depths at which magmas are stored, their pre-eruptive volatile contents, and the rates at which they ascend to the Earth\u0027s surface are important controls on the dynamics of volcanic eruptions. Basaltic magmas are likely to be vapor undersaturated as they begin their ascent from the mantle through the crust, but volatile solubility drops with decreasing pressure. Once vapor saturation is achieved and the magma begins to degas, its pre-eruptive volatile content is determined largely by the depth at which it resides within the crust. Magma stored in deeper reservoirs tend to experience less pre-eruptive degassing and to be richer in volatiles than magma shallower reservoirs. Eruptive style is influenced by the rate at which a magma ascends from the reservoir to the surface through its effect on the efficiency of vapor bubble nucleation, growth, and coalescence. The proposed work will advance our understanding of pre-eruptive storage conditions and syn-eruptive ascent rates through a combined field and analytical research program. Volatile measurements from olivine-hosted melt inclusions will be used to systematically investigate magma storage depths and ascent rates associated with alkaline volcanism in the Erebus volcanic province. A central goal of the project is to provide a spatial and temporal framework for interpreting results from studies of present-day volcanic processes at Mt Erebus volcano. The Erebus volcanic province of Antarctica is especially well suited to this type of investigation because: (1) there are many exposed mafic scoria cones, fissure vents, and hyaloclastites (exposed in sea cliffs) that produced rapidly quenched, olivine-rich tephra; (2) existing volatile data for Ross Island MIs show that magma storage was relatively deep compared to many mafic volcanic systems; (3) some of the eruptive centers ejected mantle xenoliths, allowing for comparison of ascent rates for xenolith-bearing and xenolith-free eruptions, and comparison of ascent rates for those bearing xenoliths with times estimated from settling velocities; and (4) the cold, dry conditions in Antarctica result in excellent tephra preservation compared to tropical and even many temperate localities. The project provides new tools for assessing volcanic hazards, facilitates collaboration involving researchers from three different institutions (WHOI, U Wyoming, and U Oregon), supports the researchers\u0027 involvement in teaching, advising, and outreach, and provides an educational opportunity for a promising young postdoctoral researcher. Understanding the interrelationships among magma volatile contents, reservoir depths, and ascent rates is vital for assessing volcanic hazards associated with alkaline volcanism across the globe.\r\n\r\n", "east": 169.6, "geometry": "POINT(166.85 -77.775)", "instruments": null, "is_usap_dc": true, "keywords": "Tephra; Turtle Rock; AMD/US; USA/NSF; AMD; Ross Island; LABORATORY; Turks Head; Hut Point Peninsula; LAVA SPEED/FLOW; USAP-DC; Mt. Morning; Mt. Terror; ROCKS/MINERALS/CRYSTALS; Mt. Bird; FIELD INVESTIGATION", "locations": "Ross Island; Mt. Morning; Mt. Bird; Mt. Terror; Hut Point Peninsula; Turtle Rock; Turks Head", "north": -77.1, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Gaetani, Glenn; Le Roux, Veronique; Sims, Kenneth; Wallace, Paul", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.45, "title": "Collaborative Research: Determining Magma Storage Depths and Ascent Rates for the Erebus Volcanic Province, Antarctica Using Diffusive Water Loss from Olivine-hosted Melt Inclusion", "uid": "p0010081", "west": 164.1}, {"awards": "1443306 Mayewski, Paul; 1443263 Higgins, John", "bounds_geometry": null, "dataset_titles": "Carbon dioxide concentration and its stable carbon isotope composition in Allan Hills ice cores; Elemental and isotopic composition of heavy noble gases in Allan Hills ice cores; Elemental and isotopic composition of nitrogen, oxygen, and argon in Allan Hills ice cores; Greenhouse gas composition in the Allan Hills S27 ice core; Methane concentration in Allan Hills ice cores; Stable isotope composition of the trapped air in the Allan Hills S27 ice core; Stable water isotope data for the AH-1502 ice core drilled at the Allan Hills Blue ice area; Stable water isotope data for the AH-1503 ice core drilled at the Allan Hills Blue ice area; Stable water isotope data for the surface samples collected at the Allan Hills Blue ice area", "datasets": [{"dataset_uid": "601202", "doi": "10.15784/601202", "keywords": "Allan Hills; Allan Hills project; Antarctica; Carbon Dioxide; Carbon Isotopes; Chemistry:Ice; CO2; Cryosphere; Gas Chromatography; Glaciers/Ice Sheet; Glaciology; Greenhouse Gases; Ice; Ice Core Data; Ice Core Gas Records; Ice Core Records; Mass Spectrometer; Mass Spectrometry; Methane; Snow/Ice", "people": "Brook, Edward J.; Bender, Michael; Higgins, John; Yan, Yuzhen", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Carbon dioxide concentration and its stable carbon isotope composition in Allan Hills ice cores", "url": "https://www.usap-dc.org/view/dataset/601202"}, {"dataset_uid": "601203", "doi": "10.15784/601203", "keywords": "Allan Hills; Allan Hills project; Antarctica; Chemistry:Ice; Cryosphere; Gas Chromatography; Glaciers/Ice Sheet; Glaciology; Greenhouse Gases; Ice; Ice Core Data; Ice Core Gas Records; Methane; Snow/Ice", "people": "Brook, Edward J.; Yan, Yuzhen; Bender, Michael; Higgins, John", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Methane concentration in Allan Hills ice cores", "url": "https://www.usap-dc.org/view/dataset/601203"}, {"dataset_uid": "601512", "doi": "10.15784/601512", "keywords": "Allan Hills; Antarctica; Blue Ice; Cryosphere; Ice Core; Ice Core Gas Records; Isotope; Nitrogen; Oxygen", "people": "Bender, Michael; Higgins, John; Yan, Yuzhen", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Stable isotope composition of the trapped air in the Allan Hills S27 ice core", "url": "https://www.usap-dc.org/view/dataset/601512"}, {"dataset_uid": "601483", "doi": "10.15784/601483", "keywords": "AGDC-project; Allan Hills; Antarctica; Argon; Cryosphere; Ice; Ice Core Data; Ice Core Gas Records; Isotope; Mass Spectrometry; Nitrogen; Oxygen", "people": "Yan, Yuzhen; Higgins, John; Bender, Michael", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Elemental and isotopic composition of nitrogen, oxygen, and argon in Allan Hills ice cores", "url": "https://www.usap-dc.org/view/dataset/601483"}, {"dataset_uid": "601128", "doi": "10.15784/601128", "keywords": "Allan Hills; Antarctica; Blue Ice Area; Chemistry:Ice; Cryosphere; Delta 18O; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Isotope record; Mass Spectrometry; Stable water isotopes", "people": "Introne, Douglas; Yan, Yuzhen; Mayewski, Paul A.; Kurbatov, Andrei V.", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Stable water isotope data for the AH-1503 ice core drilled at the Allan Hills Blue ice area", "url": "https://www.usap-dc.org/view/dataset/601128"}, {"dataset_uid": "601129", "doi": "10.15784/601129", "keywords": "Allan Hills; Allan Hills project; Antarctica; Blue Ice Area; Cryosphere; Delta 18O; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Chemistry; Ice Core Records; isotope data; Oxygen; Snow/Ice; Stable water isotopes; Transantarctic Mountains", "people": "Kurbatov, Andrei V.; Introne, Douglas; Yan, Yuzhen; Mayewski, Paul A.", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Stable water isotope data for the AH-1502 ice core drilled at the Allan Hills Blue ice area", "url": "https://www.usap-dc.org/view/dataset/601129"}, {"dataset_uid": "601130", "doi": "10.15784/601130", "keywords": "Allan Hills; Allan Hills project; Antarctica; Blue Ice Area; Chemistry:Ice; Cryosphere; Delta 18O; Delta Deuterium; Glaciers/Ice Sheet; Glaciology; Ice Core Gas Records; Ice Core Records; Oxygen; Snow/Ice; Stable water isotopes; Transantarctic Mountains", "people": "Introne, Douglas; Yan, Yuzhen; Kurbatov, Andrei V.; Mayewski, Paul A.", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Stable water isotope data for the surface samples collected at the Allan Hills Blue ice area", "url": "https://www.usap-dc.org/view/dataset/601130"}, {"dataset_uid": "601201", "doi": "10.15784/601201", "keywords": "Allan Hills; Allan Hills project; Antarctica; Argon; Chemistry:Ice; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Data; Ice Core Gas Records; Krypton; Mass Spectrometer; Noble Gas; Snow/Ice; Xenon", "people": "Yan, Yuzhen; Ng, Jessica; Higgins, John; Bender, Michael; Severinghaus, Jeffrey P.", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Elemental and isotopic composition of heavy noble gases in Allan Hills ice cores", "url": "https://www.usap-dc.org/view/dataset/601201"}, {"dataset_uid": "601425", "doi": "10.15784/601425", "keywords": "Allan Hills; Antarctica; Blue Ice; Carbon Dioxide; Cryosphere; Ice Core; Methane", "people": "Yan, Yuzhen; Brook, Edward J.", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Greenhouse gas composition in the Allan Hills S27 ice core", "url": "https://www.usap-dc.org/view/dataset/601425"}], "date_created": "Thu, 18 Oct 2018 00:00:00 GMT", "description": "Bubbles of ancient air trapped in ice cores permit the direct reconstruction of atmospheric composition and allow us to link greenhouse gases and global climate over the last 800,000 years. Previous field expeditions to the Allan Hills blue ice area, Antarctica, have recovered ice cores that date to one million years, the oldest ice cores yet recovered from Antarctica. These records have revealed that interglacial CO2 concentrations decreased by 800,000 years ago and that, in the warmer world 1 million years ago, CO2 and Antarctic temperature were linked as during the last 800,000 years. This project will return to the Allan Hills blue ice area to recover additional ice cores that date to 1 million years or older. The climate records developed from the drilled ice cores will provide new insights into the chemical composition of the atmosphere and Antarctic climate during times of comparable or even greater warmth than the present day. Our results will help answer questions about issues associated with anthropogenic change. These include the relationship between temperature change and the mass balance of Antarctic ice; precipitation and aridity variations associated with radiatively forced climate change; and the climate significance of sea ice extent. The project will entrain two graduate students and a postdoctoral scholar, and will conduct outreach including workshops to engage teachers in carbon science and ice cores.\u003cbr/\u003e\u003cbr/\u003eBetween about 2.8-0.9 million years ago, Earth\u0027s climate was characterized by 40,000-year cycles, driven or paced by changes in the tilt of Earth\u0027s spin axis. Much is known about the \"40,000-year\" world from studies of deep-sea sediments, but our understanding of climate change during this period is incomplete because we lack records of Antarctic climate and direct records of atmospheric greenhouse gas concentrations. We propose to address these issues by building on our recent studies of ancient ice from the Main Ice Field, Allan Hills, Antarctica. During previous field seasons we recovered ice extending, discontinuously, from 0.1-1.0 million years old. Ice was dated by measuring the 40Ar/38Ar (Argon) ratio of the trapped gases. Our discovery of million year-old ice demonstrates that there is gas-record-quality ice from the 40,000-year world in the Allan Hills Main Ice Field. We have identified two different sites, each overlying bedrock at ~ 200 m depth, that are attractive targets for coring ice dating to 1 million years and older. This project aims to core the ice at these two sites, re-occupy a previous site with million year-old ice and drill it down to the bedrock, and generate 10-20 short (~10-meter) cores in areas where our previous work and terrestrial meteorite ages suggest ancient surface ice. We plan to date the ice using the 40Ar/38Ar ages of trapped Argon. We also plan to characterize the continuity of our cores by measuring the deuterium and oxygen isotope ratios in the ice, methane, ratios of Oxygen and Argon to Nitrogen in trapped gas, the Nitrogen-15 isotope (d15N) of Nitrogen, and the Oxygen-18 isotope (d18O) of Oxygen. As the ice may be stratigraphically disturbed, these measurements will provide diagnostic properties for assessing the continuity of the ice-core records. Successful retrieval of ice older than one million years will provide the opportunity for follow-up work to measure the CO2 concentration and other properties within the ice to inform on the temperature history of the Allan Hills region, dust sources and source-area aridity, moisture sources, densification conditions, global average ocean temperature, and greenhouse gas concentrations. We will analyze the data in the context of leading hypotheses of the 40,000-year world and the Mid-Pleistocene Transition to the 100,000-year world. We expect to advance understanding of climate dynamics during these periods.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES", "is_usap_dc": true, "keywords": "AMD/US; USA/NSF; FIELD INVESTIGATION; AMD; USAP-DC; Allan Hills; ice cores; LABORATORY", "locations": "Allan Hills", "north": null, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Mayewski, Paul A.; Kurbatov, Andrei V.; Higgins, John; Bender, Michael", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Allan Hills", "south": null, "title": "Collaborative Research: Window into the World with 40,000-year Glacial Cycles from Climate Records in Million Year-old Ice from the Allan Hills Blue Ice Area", "uid": "p0000760", "west": null}, {"awards": "1553824 Heine, John", "bounds_geometry": "POINT(166.667 -77.85)", "dataset_titles": "Rebreather Testing for the United States Antarctic Scientific Diving Program", "datasets": [{"dataset_uid": "601024", "doi": "10.15784/601024", "keywords": "Antarctica; Cryosphere; Diving; Global; Physical Oceanography", "people": "Heine, John", "repository": "USAP-DC", "science_program": null, "title": "Rebreather Testing for the United States Antarctic Scientific Diving Program", "url": "https://www.usap-dc.org/view/dataset/601024"}], "date_created": "Fri, 26 May 2017 00:00:00 GMT", "description": "There are a number of areas of Antarctic research by scientists from the United States where rebreather technology (which unlike normal SCUBA diving releases few if any air bubbles) would be valuable tools. These include but are not limited to behavioral studies (because noise from bubbles released by standard SCUBA alters the behavior of many marine organisms), studies of communities on the underside of sea ice (because the bubbles disrupt the communities while or before they are sampled), and studies of highly stratified lake communities (because the bubbles cause mixing and because lighter line could be used to tether a diver to the surface which would probably also cause less water column disruption). The latter scientific advantage of less mixing in highly stratified (not naturally mixed) lakes is also a significant environmental advantage of rebreathers. However, for safety reasons, no US science projects will be approved for the use of rebreathers until they are tested by the US Antarctic Program (USAP). This award provides funds for the USAP Scientific Diving Officer to conduct such tests in conjunction with other diving professionals experienced in polar diving in general and specifically with rebreather technology in non-polar environments. A team of six scientific diving professionals will evaluate seven or more commercial rebreather models that are being most commonly used in non-polar scientific diving. This will be done through holes drilled or melted in sea ice at McMurdo Station, Antarctica. A limited number of test dives of the best performing models will subsequently be made in stratified lakes in the McMurdo Dry Valleys.", "east": 166.667, "geometry": "POINT(166.667 -77.85)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -77.85, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Heine, John", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.85, "title": "Rebreather Testing for the United States Antarctic Scientific Diving Program", "uid": "p0000377", "west": 166.667}, {"awards": "0539578 Alley, Richard; 0539232 Cuffey, Kurt", "bounds_geometry": "POINT(112.083 -79.467)", "dataset_titles": "Grain Size Full Population Dataset from WDC06A Core; Temperature Profile of the West Antarctic Ice Sheet Divide Deep Borehole; Temperature Reconstruction at the West Antarctic Ice Sheet Divide; Updated (2017) bubble number-density, size, shape, and modeled paleoclimate data; WAIS Divide Ice Core Vertical Thin Section Low-resolution Digital Imagery; WAIS Divide Surface and Snow-pit Data, 2009-2013; WDC 06A Mean Grain Size Data", "datasets": [{"dataset_uid": "600377", "doi": "10.15784/600377", "keywords": "Antarctica; Chemistry:Fluid; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Nitrogen; Paleoclimate; Temperature; WAIS divide; WAIS Divide Ice Core", "people": "Cuffey, Kurt M.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Temperature Reconstruction at the West Antarctic Ice Sheet Divide", "url": "https://www.usap-dc.org/view/dataset/600377"}, {"dataset_uid": "609656", "doi": "10.7265/N5MC8X08", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Grain Size; Ice Core Records; WAIS divide; WAIS Divide Ice Core", "people": "Fitzpatrick, Joan; Cravens, Eric D.", "repository": "USAP-DC", "science_program": null, "title": "WDC 06A Mean Grain Size Data", "url": "https://www.usap-dc.org/view/dataset/609656"}, {"dataset_uid": "609655", "doi": "10.7265/N5VX0DG0", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Grain Size; Ice Core Records; WAIS divide; WAIS Divide Ice Core", "people": "Cravens, Eric D.; Fitzpatrick, Joan", "repository": "USAP-DC", "science_program": null, "title": "Grain Size Full Population Dataset from WDC06A Core", "url": "https://www.usap-dc.org/view/dataset/609655"}, {"dataset_uid": "609654", "doi": "10.7265/N5GM858X", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Ice Core Records; Photo/Video; Thin Sections; WAIS divide; WAIS Divide Ice Core", "people": "Cravens, Eric D.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "WAIS Divide Ice Core Vertical Thin Section Low-resolution Digital Imagery", "url": "https://www.usap-dc.org/view/dataset/609654"}, {"dataset_uid": "601079", "doi": "10.15784/601079", "keywords": "Antarctica; Atmosphere; AWS; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Meteorology; Physical Properties; Snow Pit; Temperature; WAIS divide; WAIS Divide Ice Core; WeatherStation", "people": "Alley, Richard; Fegyveresi, John", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "WAIS Divide Surface and Snow-pit Data, 2009-2013", "url": "https://www.usap-dc.org/view/dataset/601079"}, {"dataset_uid": "601224", "doi": "10.15784/601224", "keywords": "Antarctic; Antarctica; Bubble Number-Density; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice; Ice Core Data; Ice Core Records; NSF-ICF Microtome and Photography Stage; Paleoclimate; Physical Properties; Snow/Ice; WAIS Divide Ice Core; West Antarctic Ice Sheet", "people": "Voigt, Donald E.; Fitzpatrick, Joan; Fegyveresi, John; Alley, Richard; Spencer, Matthew", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Updated (2017) bubble number-density, size, shape, and modeled paleoclimate data", "url": "https://www.usap-dc.org/view/dataset/601224"}, {"dataset_uid": "609550", "doi": "10.7265/N5V69GJW", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Temperature; WAIS divide; WAIS Divide Ice Core", "people": "Clow, Gary D.; Cuffey, Kurt M.", "repository": "USAP-DC", "science_program": null, "title": "Temperature Profile of the West Antarctic Ice Sheet Divide Deep Borehole", "url": "https://www.usap-dc.org/view/dataset/609550"}], "date_created": "Thu, 12 Jan 2017 00:00:00 GMT", "description": "0539578\u003cbr/\u003eAlley \u003cbr/\u003eThis award supports a five-year collaborative project to study the physical-properties of the planned deep ice core and the temperature of the ice in the divide region of the West Antarctic Ice Sheet. The intellectual merit of the proposed research is to provide fundamental information on the state of the ice sheet, to validate the integrity of the climate record, to help reconstruct the climate record, and to understand the flow state and history of the ice sheet. This information will initially be supplied to other investigators and then to the public and to appropriate databases, and will be published in the refereed scientific literature. The objectives of the proposed research are to aid in dating of the core through counting of annual layers, to identify any exceptionally warm intervals in the past through counting of melt layers, to learn as much as possible about the flow state and history of the ice through measurement of size, shape and arrangements of bubbles, clathrate inclusions, grains and their c-axes, to identify any flow disturbances through these indicators, and to learn the history of snow accumulation and temperature from analyses of bubbles and borehole temperatures combined with flow modeling and use of data from other collaborators. These results will then be synthesized and communicated. Failure to examine cores can lead to erroneous identification of flow features as climate changes, so careful examination is required. Independent reconstruction of accumulation rate provides important data on climate change, and improves confidence in interpretation of other climate indicators. Borehole temperatures are useful recorders of temperature history. Flow state and history are important in understanding climate history and potential contribution of ice to sea-level change. By contributing to all of these and additional issues, the proposed research will be of considerable value. The broader impacts of the research include making available to the public improved knowledge on societally central questions involving abrupt climate change and sea-level rise. The project will also contribute to the education of advanced students, will utilize results in education of introductory students, and will make vigorous efforts in outreach, informal science education, and supplying information to policy-makers as requested, thus contributing to a more-informed society.", "east": 112.083, "geometry": "POINT(112.083 -79.467)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e CAMERAS \u003e CAMERA; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e THERMISTORS \u003e THERMISTORS", "is_usap_dc": true, "keywords": "GROUND-BASED OBSERVATIONS; LABORATORY; WAIS Divide-project; AGDC-project; Bubble Number-Density; WAIS divide; Ice Core; Temperature Profiles; FIELD SURVEYS", "locations": "WAIS divide", "north": -79.467, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Fitzpatrick, Joan; Alley, Richard; Fegyveresi, John; Clow, Gary D.; Cuffey, Kurt M.; Cravens, Eric D.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.467, "title": "Collaborative Research: Physical Properties of the WAIS Divide Deep Core", "uid": "p0000038", "west": 112.083}, {"awards": "1142173 Bay, Ryan; 1142010 Talghader, Joseph", "bounds_geometry": "POINT(112.085 -79.467)", "dataset_titles": "Optical Fabric and Fiber Logging of Glacial Ice (1142010)", "datasets": [{"dataset_uid": "600172", "doi": "10.15784/600172", "keywords": "Antarctica; Ash Layer; Borehole Camera; Cryosphere; Glaciology; Ice Core Records; WAIS divide; WAIS Divide Ice Core", "people": "Talghader, Joseph", "repository": "USAP-DC", "science_program": null, "title": "Optical Fabric and Fiber Logging of Glacial Ice (1142010)", "url": "https://www.usap-dc.org/view/dataset/600172"}], "date_created": "Thu, 05 Nov 2015 00:00:00 GMT", "description": "1142010/Talghader\u003cbr/\u003e\u003cbr/\u003eThis award supports a project to combine the expertise of both glaciologists and optical engineers to develop polarization- preserving optical scattering techniques for borehole tools to identify changes in high-resolution crystal structure (fabric) and dust content of glacial ice. The intellectual merit of this work is that the fabric and impurity content of the ice contain details on climate, volcanic activity and ice flow history. Such fabric measurements are currently taken by slicing an ice core into sections after it has started to depressurize which is an extremely time-intensive process that damages the core and does not always preserve the properties of ice in its in-situ state. In addition the ice core usually must be consumed in order to measure the components of the dust. The fabric measurements of this study utilize the concept that singly-scattered light in ice preserves most of its polarization when it is backscattered once from bubbles or dust; therefore, changes to the polarization of singly-backscattered light must originate with the birefringence. Measurements based on this concept will enable this program to obtain continuous records of fabric and correlate them to chronology and dust content. The project will also develop advanced borehole instruments to replace current logging tools, which require optical sources, detectors and power cables to be submerged in borehole fluid and lowered into the ice sheet at temperatures of -50oC. The use of telecommunications fiber will allow all sources and detectors to remain at the surface and enable low-noise signal processing techniques such as lock-in amplification that increase signal integrity and reduce needed power. Further, fiber logging systems would be much smaller and more flexible than current tools and capable of navigating most boreholes without a heavy winch. In order to assess fabric in situ and test fiber-optic borehole tools, field measurements will be made at WAIS Divide and a deep log will also be made at Siple Dome, both in West Antarctica. If successful, the broader impacts of the proposed research would include the development of new analytical methods and lightweight logging tools for ice drilling research that can operate in boreholes drilled in ice. Eventually the work could result in the development of better prehistoric records of glacier flow, atmospheric particulates, precipitation, and climate forcing. The project encompasses a broad base of theoretical, experimental, and design work, which makes it ideal for training graduate students and advanced undergraduates. Collaboration with schools and classroom teachers will help bring aspects of optics, climate, and polar science to an existing Middle School curriculum.", "east": 112.085, "geometry": "POINT(112.085 -79.467)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES; IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e OPTICAL DUST LOGGERS", "is_usap_dc": true, "keywords": "Fabric; Dust; Not provided; optical scattering; FIELD SURVEYS; chronology; Ice Core; Siple Dome; LABORATORY; WAIS divide; Antarctic; crystal structure; FIELD INVESTIGATION; Borehole", "locations": "Antarctic; WAIS divide; Siple Dome", "north": -79.467, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Talghader, Joseph; Bay, Ryan", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; Not provided; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -79.467, "title": "Optical Fabric and Fiber Logging of Glacial Ice", "uid": "p0000339", "west": 112.085}, {"awards": "1143619 Severinghaus, Jeffrey", "bounds_geometry": "POINT(-112.09 -79.47)", "dataset_titles": null, "datasets": null, "date_created": "Mon, 13 Jul 2015 00:00:00 GMT", "description": "This award supports a project to extend the study of gases in ice cores to those gases whose small molecular diameters cause them to escape rapidly from ice samples (the so-called \"fugitive gases\"). The work will employ helium, neon, argon, and oxygen measurements in the WAIS Divide ice core to better understand the mechanism of the gas close-off fractionation that occurs while air bubbles are incorporated into ice. The intellectual merit of the proposed work is that corrections for this fractionation using neon (which is constant in the atmosphere) may ultimately enable the first ice core-based atmospheric oxygen and helium records. Neon may also illuminate the mechanistic link between local insolation and oxygen used for astronomical dating of ice cores. Helium measure-ments in the deepest ~100 m of the core will also shed light on the stratigraphic integrity of the basal ice, and serve as a probe of solid earth-ice interaction at the base of the West Antarctic ice sheet. Past atmospheric oxygen records, currently unavailable prior to 1989 CE, would reveal changes in the size of the terrestrial biosphere carbon pool that accompany climate variations and place constraints on the biogeochemical feedback response to future warming. An atmospheric helium-3/helium-4 record would test the hypothesis that the solar wind (which is highly enriched in helium-3) condensed directly into Earth?s atmosphere during the collapse of the geomagnetic field that occurred 41,000 years ago, known as the Laschamp Event. Fugitive-gas samples will be taken on-site immediately after recovery of the ice core by the PI and one postdoctoral scholar, under the umbrella of an existing project to support replicate coring and borehole deepening. This work will add value to the scientific return from field work activity with little additional cost to logistical resources. The broader impacts of the work on atmospheric oxygen are that it may increase understanding of how terrestrial carbon pools and atmospheric greenhouse gas sources will respond in a feedback sense to the coming warming. Long-term atmospheric oxygen trends are also of interest for understanding biogeochemical regulatory mechanisms and the impact of atmospheric evolution on life. Helium records have value in understanding the budget of this non-renewable gas and its implications for space weather and solar activity. The project will train one graduate student and one postdoctoral scholar. The fascination of linking solid earth, cryosphere, atmosphere, and space weather will help to entrain and excite young scientists and efforts to understand the Earth as a whole interlinked system will provide fuel to outreach efforts at all ages.", "east": -112.09, "geometry": "POINT(-112.09 -79.47)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS", "is_usap_dc": false, "keywords": "Basal Processes; Not provided; Neon; FIELD INVESTIGATION; WAIS divide; tracers; Helium; Past Biospheric Carbon Storage; FIELD SURVEYS; LABORATORY; Fugitive Gases; Antarctica", "locations": "WAIS divide; Antarctica", "north": -79.47, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Severinghaus, Jeffrey P.", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repositories": null, "science_programs": null, "south": -79.47, "title": "Fugitive Gases (Helium, Neon, and Oxygen) in the WAIS Divide Ice Core as Tracers of Basal Processes and Past Biospheric Carbon Storage", "uid": "p0000441", "west": -112.09}, {"awards": "0838843 Kurbatov, Andrei; 0838849 Bender, Michael", "bounds_geometry": "POLYGON((159.16667 -76.66667,159.19167 -76.66667,159.21667 -76.66667,159.24167 -76.66667,159.26667 -76.66667,159.29167 -76.66667,159.31667 -76.66667,159.34167 -76.66667,159.36667 -76.66667,159.39167 -76.66667,159.41667 -76.66667,159.41667 -76.673336,159.41667 -76.680002,159.41667 -76.686668,159.41667 -76.693334,159.41667 -76.7,159.41667 -76.706666,159.41667 -76.713332,159.41667 -76.719998,159.41667 -76.726664,159.41667 -76.73333,159.39167 -76.73333,159.36667 -76.73333,159.34167 -76.73333,159.31667 -76.73333,159.29167 -76.73333,159.26667 -76.73333,159.24167 -76.73333,159.21667 -76.73333,159.19167 -76.73333,159.16667 -76.73333,159.16667 -76.726664,159.16667 -76.719998,159.16667 -76.713332,159.16667 -76.706666,159.16667 -76.7,159.16667 -76.693334,159.16667 -76.686668,159.16667 -76.680002,159.16667 -76.673336,159.16667 -76.66667))", "dataset_titles": "Allan Hills Stable Water Isotopes; Exploring A 2 Million + Year Ice Climate Archive-Allan Hills Blue Ice Area (2MBIA)", "datasets": [{"dataset_uid": "609541", "doi": "10.7265/N5NP22DF", "keywords": "Allan Hills; Antarctica; Chemistry:Ice; Cryosphere; Geochemistry; Glaciers/Ice Sheet; Glaciology; Isotope", "people": "Mayewski, Paul A.; Kurbatov, Andrei V.; Spaulding, Nicole; Introne, Douglas", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Allan Hills Stable Water Isotopes", "url": "https://www.usap-dc.org/view/dataset/609541"}, {"dataset_uid": "600099", "doi": "10.15784/600099", "keywords": "Allan Hills; Antarctica; Chemistry:Ice; Cryosphere; Geochemistry; Ice Core Records; Paleoclimate; Solid Earth", "people": "Bender, Michael", "repository": "USAP-DC", "science_program": "Allan Hills", "title": "Exploring A 2 Million + Year Ice Climate Archive-Allan Hills Blue Ice Area (2MBIA)", "url": "https://www.usap-dc.org/view/dataset/600099"}], "date_created": "Wed, 10 Dec 2014 00:00:00 GMT", "description": "This award supports a project to generate an absolute timescale for the Allan Hills Blue Ice Area (BIA), and then to reconstruct details of past climate changes and greenhouse gas concentrations for certain time periods back to 2.5 Ma. Ice ages will be determined by applying emerging methods for absolute and relative dating of trapped air bubbles (based on Argon-40/Argon-38, delta-18O of O2, and the O2/N2 ratio). To demonstrate the potential of the Allan Hills BIAs as a paleoclimate archive trenches and ice cores will be collected for age intervals corresponding to 110-140 ka, 1 Ma, and 2.5 Ma. During the proposed two field seasons a total of 6x100 m and additional 15 m cores will be combined with trenching. The intellectual merit of the proposed activity is that the results of this work will extend the landmark work of EPICA and other deep ice coring efforts, which give records dating back to 0.8 Ma, and will complement work planned by IPICS to drill a continuous Antarctic ice core extending to 1.5 Ma. The results will help to advance understanding of major climate regimes and transitions that took place between 0-2.5 Ma, including the 40 kyr world and the mid-Pleistocene climate transition. A major long-term scientific goal is to provide a transformative approach to the collection of paleoclimate records by establishing an \"International Climate Park\" in the Allan Hills BIA that would enable sampling of large quantities of known age ice as old as 2.5 Ma, by any interested American or foreign investigator. The broader impacts resulting from the proposed activity include training students who are well versed in advanced field, laboratory and numerical modeling methods combining geochemistry, glaciology, and paleoclimatology. We will include material relevant to our proposed research in our ongoing efforts in local education and in our outreach efforts for media. The University of Maine already has cyberinfrastructure, using state of the art web-based technology, which can provide a wide community of scientists with fast access to the results of our research. The work will contribute to the broad array of climate change studies that is informing worldwide understanding of natural and anthropogenic forced climate change, and the options for responding. This award has field work in Antarctica.", "east": 159.41667, "geometry": "POINT(159.29167 -76.7)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS", "is_usap_dc": true, "keywords": "Not provided; GROUND-BASED OBSERVATIONS; LABORATORY; Oxygen Isotopes; Deuterium Isotopes", "locations": null, "north": -76.66667, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Spaulding, Nicole; Introne, Douglas; Bender, Michael; Kurbatov, Andrei V.; Mayewski, Paul A.", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Allan Hills", "south": -76.73333, "title": "Collaborative Research: Exploring A 2 Million + Year Ice Climate Archive-Allan Hills Blue Ice Area (2MBIA)", "uid": "p0000046", "west": 159.16667}, {"awards": "0944078 Albert, Mary", "bounds_geometry": "POINT(112.05 79.28)", "dataset_titles": "Firn Permeability and Density at WAIS Divide", "datasets": [{"dataset_uid": "609602", "doi": "10.7265/N57942NT", "keywords": "Antarctica; Cryosphere; Firn; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Physical Properties; WAIS divide; WAIS Divide Ice Core", "people": "Albert, Mary R.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Firn Permeability and Density at WAIS Divide", "url": "https://www.usap-dc.org/view/dataset/609602"}], "date_created": "Fri, 15 Aug 2014 00:00:00 GMT", "description": "This award supports a project to investigate the transformations from snow to firn to ice and the underlying physics controlling firn\u0027s ability to store atmospheric samples from the past. Senior researchers, a graduate student, and several undergraduates will make high-resolution measurements of both the diffusivity and permeability profiles of firn cores from several sites in Antarctica and correlate the results with their microstructures quantified using advanced materials characterization techniques (scanning electron microscopy and x-ray computed tomography). The use of cores from different sites will enable us to examine the influence of different local climate conditions on the firn structure. We will use the results to help interpret existing measurements of firn air chemical composition at several sites where firn air measurements exist. There are three closely-linked goals of this project: to quantify the dependence of interstitial transport properties on firn microstructure from the surface down to the pore close-off depth, to determine at what depths bubbles form and entrap air, and investigate the extent to which these features exhibit site-to-site differences, and to use the measurements of firn air composition and firn structure to better quantify the differences between atmospheric composition (present and past), and the air trapped in both the firn and in air bubbles within ice by comparing the results of the proposed work with firn air measurements that have been made at the WAIS Divide and Megadunes sites. The broader impacts of this project are that the study will this study will enable us to elucidate the fundamental controls on the metamorphism of firn microstructure and its impact on processes of gas entrapment that are important to understanding ice core evidence of past atmospheric composition and climate change. The project will form the basis for the graduate research of a PhD student at Dartmouth, with numerous opportunities for undergraduate involvement in cold room measurements and outreach. The investigators have a track record of successfully mentoring women students, and will build on this experience. In conjunction with local earth science teachers, and graduate and undergraduate students will design a teacher-training module on the role of the Polar Regions in climate change. Once developed and tested, this module will be made available to the broader polar research community for their use with teachers in their communities.", "east": -112.05, "geometry": "POINT(-112.05 -79.28)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e MICROTOMOGRAPHY; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e MICROSCOPES; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e SCANNING ELECTRON MICROSCOPES", "is_usap_dc": true, "keywords": "Not provided; Firn Permeability; Firn Air; LABORATORY; AGDC-project; WAIS Divide-project; Visual Observations; FIELD SURVEYS; GROUND-BASED OBSERVATIONS; Antarctica; Ice; AGDC; Firn; Megadunes; Tomography; WAIS divide; Microstructure; Density; Firn Core; FIELD INVESTIGATION; physics", "locations": "Antarctica; WAIS divide", "north": -79.28, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Baker, Ian; Albert, Mary R.", "platforms": "LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.28, "title": "Firn Metamorphism: Microstructure and Physical Properties", "uid": "p0000049", "west": -112.05}, {"awards": "0539578 Alley, Richard", "bounds_geometry": null, "dataset_titles": "Bubble Number-density Data and Modeled Paleoclimates", "datasets": [{"dataset_uid": "609538", "doi": "10.7265/N5JW8BTJ", "repository": "USAP-DC", "science_program": null, "title": "Bubble Number-density Data and Modeled Paleoclimates", "url": "http://www.usap-dc.org/view/dataset/609538"}], "date_created": "Thu, 14 Aug 2014 00:00:00 GMT", "description": null, "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "Air Bubbles; Antarctica; Cryosphere; Digital Single Lens Reflex (DSLR) Camera; Glaciers/Ice Sheet; Glaciology; Ice Core Records", "locations": "Antarctica", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Fegyveresi, John; Alley, Richard", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": null, "uid": null, "west": null}, {"awards": "1043313 Spencer, Matthew; 1043528 Alley, Richard", "bounds_geometry": "POINT(112.1166 -79.4666)", "dataset_titles": "Average Annual Layer Thickness of the WAIS Divide Ice Core from Visual Stratigraphy; C-axis Fabric from Physical Properties Samples of the WAIS Divide Ice Core; Updated (2017) bubble number-density, size, shape, and modeled paleoclimate data; WAIS Divide 580m Bubble and Grain Hybrid Data; WAIS Divide Surface and Snow-pit Data, 2009-2013", "datasets": [{"dataset_uid": "601224", "doi": "10.15784/601224", "keywords": "Antarctic; Antarctica; Bubble Number-Density; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice; Ice Core Data; Ice Core Records; NSF-ICF Microtome and Photography Stage; Paleoclimate; Physical Properties; Snow/Ice; WAIS Divide Ice Core; West Antarctic Ice Sheet", "people": "Voigt, Donald E.; Fitzpatrick, Joan; Fegyveresi, John; Alley, Richard; Spencer, Matthew", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Updated (2017) bubble number-density, size, shape, and modeled paleoclimate data", "url": "https://www.usap-dc.org/view/dataset/601224"}, {"dataset_uid": "601087", "doi": "10.15784/601087", "keywords": "Air Bubbles; Antarctica; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Ice Strain; Physical Ice Properties; Snow/Ice; Strain", "people": "Alley, Richard; Fegyveresi, John", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "WAIS Divide 580m Bubble and Grain Hybrid Data", "url": "https://www.usap-dc.org/view/dataset/601087"}, {"dataset_uid": "601079", "doi": "10.15784/601079", "keywords": "Antarctica; Atmosphere; AWS; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Meteorology; Physical Properties; Snow Pit; Temperature; WAIS divide; WAIS Divide Ice Core; WeatherStation", "people": "Alley, Richard; Fegyveresi, John", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "WAIS Divide Surface and Snow-pit Data, 2009-2013", "url": "https://www.usap-dc.org/view/dataset/601079"}, {"dataset_uid": "609603", "doi": "10.7265/N53J39X3", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; WAIS divide; WAIS Divide Ice Core", "people": "Spencer, Matthew", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Average Annual Layer Thickness of the WAIS Divide Ice Core from Visual Stratigraphy", "url": "https://www.usap-dc.org/view/dataset/609603"}, {"dataset_uid": "609605", "doi": "10.7265/N5W093VM", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Physical Properties; WAIS divide; WAIS Divide Ice Core", "people": "Voigt, Donald E.; Alley, Richard; Fitzpatrick, Joan", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "C-axis Fabric from Physical Properties Samples of the WAIS Divide Ice Core", "url": "https://www.usap-dc.org/view/dataset/609605"}], "date_created": "Tue, 19 Jun 2012 00:00:00 GMT", "description": "1043528/Alley\u003cbr/\u003e\u003cbr/\u003eThis award supports a project to complete the physical-properties studies of the WAIS Divide deep ice core, now being collected in West Antarctica. Ongoing work funded by NSF, under a grant that is ending, has produced visible stratigraphy dating, inspection of the core for any melt layers, volcanic horizons, flow disturbances or other features, analysis of bubble number-densities allowing reconstruction of a two-millennial cooling trend in the latter Holocene at the site, characterization of other bubble characteristics (size, etc.), density studies, characterization of snow-surface changes at the site, preliminary c-axis studies, and more. The current proposal seeks to complete this work, once the rest of the core is recovered. The intellectual merit of the proposed activity starts with quality assurance for the core, by visual detection of any evidence of flow disturbances that would disrupt the integrity of the climate record. Inspection will also reveal any melt layers, volcanic horizons, etc. Annual-layer dating will be conducted; thus far, the visible strata have not been as useful as some other indicators, but the possibility (based on experience in Greenland) that visible examination will allow detection of thinner annual layers than other techniques motivates the effort. Bubble number-density will be used to reconstruct temperature changes through the rest of the bubbly part of the core, providing important paleoclimatic data for earlier parts of the Holocene. Coordinated interpretation of c-axis fabrics, grain sizes and shapes, and bubble characteristics will be used to learn about the history of ice flow, the processes of ice flow, and the softness of the ice for additional deformation. Analysis of surface data already collected will improve interpretation of the layering of the core. It is possible that the annual-layer dating will not be sufficiently successful, and that the core will be undisturbed with no melt layers; if so, then these efforts will not yield major publications. However, success of the other efforts should produce improved understanding of the history and stability of the ice sheet, and key processes controlling these, and the quality assurance provided by the visual examination is important for the project as a whole. The broader impacts of the proposed activity include education of a PhD student and multiple undergraduates, and research opportunities for a junior faculty member at an undergraduate institution. The proposed activity will help support an especially vigorous education and outreach effort providing undergraduate instruction for over 1000 students per year, reaching thousands more citizens and many policymakers, and preparing educational materials used at many levels.", "east": 112.1166, "geometry": "POINT(112.1166 -79.4666)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e VISUAL OBSERVATIONS; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e MICROSCOPES; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e SCANNING ELECTRON MICROSCOPES; IN SITU/LABORATORY INSTRUMENTS \u003e CHEMICAL METERS/ANALYZERS \u003e ACFA; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES; NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE; NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "GROUND-BASED OBSERVATIONS; Antarctic; Antarctica; Annual Layer Thickness; annual layers; Ice Core; Visual Observations; FIELD SURVEYS; bubbles; LABORATORY; FIELD INVESTIGATION; Physical Properties; Stratigraphy; bubble density; WAIS divide; c-axes; AGDC-project; C-axis; ice fabric; Not provided; AGDC; WAIS Divide-project; Model; melt layers; climate record", "locations": "WAIS divide; Antarctica; Antarctic", "north": -79.4666, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Glaciology; Antarctic Glaciology; Antarctic Earth Sciences", "paleo_time": null, "persons": "Spencer, Matthew; Alley, Richard; Fitzpatrick, Joan; Voigt, Donald E.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; Not provided; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.4666, "title": "Collaborative Research: Continued Study of Physical Properties of the WAIS Divide Deep Core", "uid": "p0000027", "west": 112.1166}, {"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": "LABORATORY; Ice Core; FIELD SURVEYS; Firn; FIELD INVESTIGATION; Climate Change; internal layers; Accumulation; Ice Sheet; Glaciology", "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": "0538657 Severinghaus, Jeffrey", "bounds_geometry": null, "dataset_titles": "Borehole Temperature Measurement in WDC05A in January 2008 and January 2009; Low-res d15N and d18O of O2 in the WAIS Divide 06A Deep Core; Ultra-High Resolution LA-ICP-MS Results: DO-21 Rapid Warming Event; WAIS Divide d18Oatm and Siple Dome/WAIS Divide composite and individual delta epsilon LAND", "datasets": [{"dataset_uid": "609637", "doi": "10.7265/N5B27S7S", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Temperature; WAIS divide; WAIS Divide Ice Core", "people": "Orsi, Anais J.; Severinghaus, Jeffrey P.", "repository": "USAP-DC", "science_program": null, "title": "Borehole Temperature Measurement in WDC05A in January 2008 and January 2009", "url": "https://www.usap-dc.org/view/dataset/609637"}, {"dataset_uid": "609635", "doi": "10.7265/N51J97PS", "keywords": "Arctic; Cryosphere; Geochemistry; GISP; Glaciers/Ice Sheet; Ice Core Records; Paleoclimate", "people": "Mayewski, Paul A.; Kurbatov, Andrei V.; Haines, Skylar", "repository": "USAP-DC", "science_program": null, "title": "Ultra-High Resolution LA-ICP-MS Results: DO-21 Rapid Warming Event", "url": "https://www.usap-dc.org/view/dataset/609635"}, {"dataset_uid": "609660", "doi": "10.7265/N5S46PWD", "keywords": "Antarctica; Chemistry:Fluid; Cryosphere; Geochemistry; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Paleoclimate; WAIS divide; WAIS Divide Ice Core", "people": "Severinghaus, Jeffrey P.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Low-res d15N and d18O of O2 in the WAIS Divide 06A Deep Core", "url": "https://www.usap-dc.org/view/dataset/609660"}, {"dataset_uid": "601041", "doi": "10.15784/601041", "keywords": "Antarctica; Chemistry:Ice; Cryosphere; Gas; Geochemistry; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Isotope; WAIS Divide Ice Core", "people": "Severinghaus, Jeffrey P.; Seltzer, Alan", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "WAIS Divide d18Oatm and Siple Dome/WAIS Divide composite and individual delta epsilon LAND", "url": "https://www.usap-dc.org/view/dataset/601041"}], "date_created": "Thu, 08 Jul 2010 00:00:00 GMT", "description": "0538657\u003cbr/\u003eSeveringhaus\u003cbr/\u003eThis award supports a project to develop high-resolution (20-yr) nitrogen and oxygen isotope records on trapped gases in the WAIS Divide ice core (Antarctica), with a comparison record for chronological purposes in the GISP2 (Greenland) ice core. The main scientific objective is to provide an independent temperature-change record for the past 100,000 years in West Antarctica that is not subject to the uncertainty inherent in ice isotopes (18O and deuterium), the classical paleothermometer. Nitrogen isotopes (Delta 15N) in air bubbles in glacial ice record rapid surface temperature change because of thermal fractionation of air in the porous firn layer, and this isotopic anomaly is recorded in bubbles as the firn becomes ice. Using this gas-based temperature-change record, in combination with methane data as interpolar stratigraphic markers, the proposed work will define the precise relative timing of abrupt warming in Greenland and abrupt cooling at the WAIS Divide site during the millennial-scale climatic oscillations of Marine Isotopic Stage 3 (30-70 kyr BP) and the last glacial termination. The nitrogen isotope record also provides constraints on past firn thickness, which inform temperature and accumulation rate histories from the ice core. A search for possible solar-related cycles will be conducted with the WAIS Divide Holocene (Delta 15N.) Oxygen isotopes of O2 (Delta 18Oatm) are obtained as a byproduct of the (Delta 15N) measurement. The gas-isotopic records will enhance the value of other atmospheric gas measurements in WAIS Divide, which are expected to be of unprecedented quality. The high-resolution (Delta 18Oatm) records will provide chronological control for use by the international ice coring community and for surface glacier ice dating. Education of a graduate student, and training of a staff member in the laboratory, will contribute to the nation\u0027s human resource base. Outreach activities in the context of the International Polar Year will be enhanced. International collaboration is planned with the laboratory of LSCE, University of Paris.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e THERMISTORS \u003e THERMISTORS; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e LA-ICP-MS; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS", "is_usap_dc": true, "keywords": "NSIDC; AGDC-project; LABORATORY; Borehole Temperatures; WAIS Divide-project; Depth; Not provided; GROUND-BASED OBSERVATIONS; Ice Core; WAIS divide; AGDC", "locations": "WAIS divide", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": "PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY \u003e PLEISTOCENE", "persons": "Haines, Skylar; Mayewski, Paul A.; Orsi, Anais J.; Kurbatov, Andrei V.; Severinghaus, Jeffrey P.", "platforms": "Not provided; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": null, "title": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate", "uid": "p0000036", "west": null}, {"awards": "0125794 Price, P. Buford", "bounds_geometry": null, "dataset_titles": "Optical Logging for Dust and Microbes in Boreholes in Glacial Ice", "datasets": [{"dataset_uid": "609403", "doi": "10.7265/N59P2ZKB", "keywords": "Antarctica; Cryosphere; Dust; Geology/Geophysics - Other; Glaciers/Ice Sheet; Glaciology; Microbiology; Optical Backscatter", "people": "Bay, Ryan", "repository": "USAP-DC", "science_program": null, "title": "Optical Logging for Dust and Microbes in Boreholes in Glacial Ice", "url": "https://www.usap-dc.org/view/dataset/609403"}], "date_created": "Wed, 29 Jul 2009 00:00:00 GMT", "description": "0125794\u003cbr/\u003ePrice\u003cbr/\u003e\u003cbr/\u003eThis award supports research in climatology, geosciences, and life in extreme environments to be carried out with a newly developed optical borehole logger. The logger fits into a fluid-filled borehole in glacial ice. It emits light at 370 nm in a horizontal plane in order to probe optical properties of particles embedded in the ice out to several meters from the borehole. After leaving the borehole, the light is partially absorbed and scattered by dust, biomolecules, or microbes. A fraction of the light is scattered back into the borehole and is detected by a system of seven phototubes, each of which collects light with high efficiency in a separate wavelength band. One of them collects light that scatters off of dust and air bubbles without wavelength shift, and serves as a dust logger. The other six are covered with notch filters that measure six different wavelength bands and measure the shape of the fluorescence spectrum of microbes and biomolecules. Thus, the same instrument serves as both a dust logger and a microbe logger. Applications include: 1) Precise chronologies and long-period solar variability. With a resolution of 1 to 2 cm for both GISP2 and Siple Dome, the logger will record annual dust maxima and evaluate claims of modulations of dust concentration with periods ranging from 11 yrs (the solar cycle) to 2300 yrs; 2) Volcanism and age-depth markers. Dozens of volcanic ash bands will be detectable and will serve as primary age-depth markers for other boreholes; 3) Microorganisms and biomolecules. The vertical distribution of living, dormant, and dead microbes can be logged, and searches for archaea and aeolian polyaromatic hydrocarbons can be made. The logging experiments will be carried out at Siple Dome and Dome C in Antarctica and at GISP2 and GRIP in Greenland.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e OPTICAL DUST LOGGERS", "is_usap_dc": true, "keywords": "LABORATORY; Ice Core Data; Paleoclimate; Not provided; Ice Core; Climate Research; Climate; FIELD INVESTIGATION; Volcanic; Climate Change; ice cores; FIELD SURVEYS", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Glaciology; Arctic Natural Sciences", "paleo_time": null, "persons": "Bay, Ryan", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Optical Logging for Dust and Microbes in Boreholes in Glacial Ice", "uid": "p0000156", "west": null}, {"awards": "0538630 Severinghaus, Jeffrey", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Wed, 01 Apr 2009 00:00:00 GMT", "description": "0538630\u003cbr/\u003eSeveringhaus\u003cbr/\u003eThis award supports a project to produce the first record of Kr/N2 in the paleo-atmosphere as measured in air bubbles trapped in ice cores. These measurements may be indicative of past variations in mean ocean temperature. Knowing the mean ocean temperature in the past will give insight into past variations in deep ocean temperature, which remain poorly understood. Deep ocean temperature variations are important for understanding the mechanisms of climate change. Krypton is highly soluble in water, and its solubility varies with temperature, with higher solubilities at colder water temperatures. A colder ocean during the last glacial period would therefore hold more krypton than today\u0027s ocean. Because the total amount of krypton in the ocean-atmosphere system is constant, the increase in the krypton inventory in the glacial ocean should cause a resultant decrease in the atmospheric inventory of krypton. The primary goal of this work is to develop the use of Kr/N2 as an indicator of paleo-oceanic mean temperature. This will involve improving the analytical technique for the Kr/N2 measurement itself, and measuring the Kr/N2 in air bubbles in ice from the last glacial maximum (LGM) and the late Holocene in the Vostok and GISP2 ice cores. This provides an estimate of LGM mean ocean temperature change, and allows for a comparison between previous estimates of deep ocean temperature during the LGM. The Vostok ice core is ideal for this purpose because of the absence of melt layers, which compromise the krypton and xenon signal. Another goal is to improve precision on the Xe/N2 measurement, which could serve as a second, independent proxy of ocean temperature change. A mean ocean temperature time series during this transition may help to explain these observations. Additionally, the proposed work will measure the Kr/N2 from marine isotope stage (MIS) 3 in the GISP2 ice core. Knowing the past ocean temperature during MIS 3 will help to constrain sea level estimates during this time period. The broader impacts of the proposed work: are that it will provide the first estimate of the extent and timing of mean ocean temperature change in the past. This will help to constrain previously proposed mechanisms of climate change involving large changes in deep ocean temperature. This project will also support the education of a graduate student. The PI gives interviews and talks to the media and public about climate change, and the work will enhance these outreach activities. Finally, the work will occur during the International Polar Year (IPY), and will underscore the unique importance of the polar regions for understanding the global atmosphere and ocean system.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "Not provided", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Severinghaus, Jeffrey P.", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": null, "title": "Paleoatmospheric Krypton and Xenon Abundances from Trapped Air in Polar Ice as Indicators of Past Mean Ocean Temperature", "uid": "p0000553", "west": null}, {"awards": "0230448 Severinghaus, Jeffrey; 0230260 Bender, Michael", "bounds_geometry": "POLYGON((-75.34 86.6,-68.742 86.6,-62.144 86.6,-55.546 86.6,-48.948 86.6,-42.35 86.6,-35.752 86.6,-29.154 86.6,-22.556 86.6,-15.958 86.6,-9.36 86.6,-9.36 83.618,-9.36 80.636,-9.36 77.654,-9.36 74.672,-9.36 71.69,-9.36 68.708,-9.36 65.726,-9.36 62.744,-9.36 59.762,-9.36 56.78,-15.958 56.78,-22.556 56.78,-29.154 56.78,-35.752 56.78,-42.35 56.78,-48.948 56.78,-55.546 56.78,-62.144 56.78,-68.742 56.78,-75.34 56.78,-75.34 59.762,-75.34 62.744,-75.34 65.726,-75.34 68.708,-75.34 71.69,-75.34 74.672,-75.34 77.654,-75.34 80.636,-75.34 83.618,-75.34 86.6))", "dataset_titles": "Firn Air Inert Gas and Oxygen Observations from Siple Dome, 1996, and the South Pole, 2001; Trapped Gas Composition and Chronology of the Vostok Ice Core", "datasets": [{"dataset_uid": "609290", "doi": "10.7265/N5FJ2DQC", "keywords": "Antarctica; Atmosphere; Chemistry:Fluid; Cryosphere; Geochemistry; Glaciology; Paleoclimate; Siple Dome; Snow/Ice; South Pole", "people": "Battle, Mark; Severinghaus, Jeffrey P.; Bender, Michael", "repository": "USAP-DC", "science_program": "Siple Dome Ice Core", "title": "Firn Air Inert Gas and Oxygen Observations from Siple Dome, 1996, and the South Pole, 2001", "url": "https://www.usap-dc.org/view/dataset/609290"}, {"dataset_uid": "609311", "doi": "10.7265/N5P26W12", "keywords": "Antarctica; Atmosphere; Chemistry:Fluid; Cryosphere; Geochronology; Glaciers/Ice Sheet; Ice Core Records; Lake Vostok; Paleoclimate; Vostok; Vostok Ice Core", "people": "Suwa, Makoto; Bender, Michael", "repository": "USAP-DC", "science_program": null, "title": "Trapped Gas Composition and Chronology of the Vostok Ice Core", "url": "https://www.usap-dc.org/view/dataset/609311"}], "date_created": "Wed, 18 Jan 2006 00:00:00 GMT", "description": "High latitude deep ice cores contain fundamental records of polar temperatures, atmospheric dust loads (and continental aridity), greenhouse gas concentrations, the status of the biosphere, and other essential properties of past environments. An accurate chronology for these records is needed if their significance is to be fully realized. The dating challenge has stimulated efforts at orbital tuning. In this approach, one varies a timescale, within allowable limits, to optimize the match between a paleoenvironmental property and a curve of insolation through time. The ideal property would vary with time due to direct insolation forcing. It would be unaffected by complex climate feedbacks and teleconnections, and it would give a clean record with high signal/noise ratio. It is argued strongly that the O2/N2 ratio of ice core trapped gases is such a property, and evidence is presented that this property, whose atmospheric ratio is nearly constant, is tied to local summertime insolation. This award will support a project to analyze the O2/N2 ratios at 1 kyr intervals from ~ 115-400 ka in the Vostok ice core. Ancillary measurements will be made of Ar/N2, and Ne/N2 and heavy noble gas ratios, in order to understand bubble close-off fractionation and its manifestation in the Vostok trapped gas record. O2/N2 variations will be matched with summertime insolation at Vostok to achieve a high-accuracy chronology for the Vostok core. The Vostok and other correlatable climate records will then be reexamined to improve our understanding of the dynamics of Pleistocene climate change.", "east": 106.8, "geometry": "POINT(106.8 -72.4667)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES; IN SITU/LABORATORY INSTRUMENTS \u003e SAMPLERS \u003e BOTTLES/FLASKS/JARS \u003e FLASKS; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES", "is_usap_dc": true, "keywords": "Paleoclimate; Siple Dome; Ice Age; Trapped Gases; Not provided; Shallow Firn Air; LABORATORY; Vostok; Firn Air Isotopes; Firn Air Isotope Measurements; ice sample gas integrity; noble gases; Thermal Fractionation; Polar Firn Air; Ice Core Chemistry; Trapped Air Bubbles; Oxygen Isotopes; Ice Core; Antarctica; South Pole; Ice Core Data; GROUND-BASED OBSERVATIONS; Gas Age; Firn Isotopes; Ice Core Gas Records; Atmospheric Gases", "locations": "Antarctica; Vostok; Siple Dome; South Pole", "north": -72.4667, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Battle, Mark; Bender, Michael; Suwa, Makoto; Severinghaus, Jeffrey P.", "platforms": "Not provided; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": -72.4667, "title": "Collaborative Research: Trapped Gas Composition and the Chronology of the Vostok Ice Core", "uid": "p0000257", "west": 106.8}, {"awards": "0125468 Severinghaus, Jeffrey", "bounds_geometry": "POLYGON((-180 -62.83,-144 -62.83,-108 -62.83,-72 -62.83,-36 -62.83,0 -62.83,36 -62.83,72 -62.83,108 -62.83,144 -62.83,180 -62.83,180 -65.547,180 -68.264,180 -70.981,180 -73.698,180 -76.415,180 -79.132,180 -81.849,180 -84.566,180 -87.283,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87.283,-180 -84.566,-180 -81.849,-180 -79.132,-180 -76.415,-180 -73.698,-180 -70.981,-180 -68.264,-180 -65.547,-180 -62.83))", "dataset_titles": null, "datasets": null, "date_created": "Tue, 01 Feb 2005 00:00:00 GMT", "description": "This award supports the continued measurements of gas isotopes in the Vostok ice core, from Antarctica. One objective is to identify the phasing of carbon dioxide variations and temperature variations, which may place constraints on hypothesized cause and effect relationships. Identification of phasing has in the past been hampered by the large and uncertain age difference between the gases trapped in air bubbles and the surrounding ice. This work will circumvent this issue by employing an indicator of temperature in the gas phase. It is argued that 40Ar/39Ar behaves as a qualitative indicator of temperature, via an indirect relationship between temperature, accumulation rate, firn thickness, and gravitational fractionation of the gas isotopes. The proposed research will make nitrogen and argon isotope measurements on ~ 200 samples of ice covering Termination II (130,000 yr B.P.) and Termination IV (340,000 yr BP). The broader impacts may include a better understanding of the role of atmospheric carbon dioxide concentrations in climate change.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": false, "keywords": "Vostok; Ice Core; Not provided; Isotope", "locations": "Vostok", "north": -62.83, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Severinghaus, Jeffrey P.", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": -90.0, "title": "Argon and nitrogen isotope measurements in the Vostok ice core as aconstraint on phasing of CO2 and temperature changes", "uid": "p0000752", "west": -180.0}, {"awards": "9615554 Fitzpatrick, Joan", "bounds_geometry": null, "dataset_titles": "Digital Images of Thin Sections from Siple Dome; Digital Imaging for Siple Dome Ice Core Analysis, Antarctica", "datasets": [{"dataset_uid": "609413", "doi": "10.7265/N5XG9P2G", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Photo/Video; Siple Dome; Siple Dome Ice Core", "people": "Alley, Richard; Fitzpatrick, Joan; Spencer, Matthew", "repository": "USAP-DC", "science_program": "Siple Dome Ice Core", "title": "Digital Imaging for Siple Dome Ice Core Analysis, Antarctica", "url": "https://www.usap-dc.org/view/dataset/609413"}, {"dataset_uid": "609127", "doi": "10.7265/N59Z92T4", "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Photo/Video; Siple Dome; Siple Dome Ice Core; WAISCORES", "people": "Fitzpatrick, Joan", "repository": "USAP-DC", "science_program": "Siple Dome Ice Core", "title": "Digital Images of Thin Sections from Siple Dome", "url": "https://www.usap-dc.org/view/dataset/609127"}], "date_created": "Wed, 14 May 2003 00:00:00 GMT", "description": "This award is for support for two years to develop the technology and methodology for digitizing the photographs and analyzing the thin sections from ice cores. In addition, the application of digital technology for whole-core stratigraphy, using digital photography, image enhancement and image processing will be investigated. The thin section analysis will be piloted with samples already in hand from the Taylor Dome ice core. If successful, these techniques will be applied to samples from the Siple Dome ice core, in cooperation with Principal Investigators already funded to retrieve and examine these sections. The original digital images with all original data annotation files will be distributed to Siple Dome principal investigators for their use in the interpretation of their own data. All software and hardware acquired for this project will become part of the permanent equipment inventory at the U.S. National Ice Core Laboratory and will be available for use by clients at the facility.", "east": null, "geometry": null, "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e CAMERAS \u003e CAMERAS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES", "is_usap_dc": true, "keywords": "NSIDC; Antarctica; Glaciology; Ice Sheet; Density; Siple; Ice Core; Stratigraphy; GROUND STATIONS; Photographs; Not provided; Ice Core Data; Siple Dome; WAISCORES; Trapped Air Bubbles; ice cores; volcanic deposits; GROUND-BASED OBSERVATIONS; Snow; Siple Coast; Chemical Composition", "locations": "Siple Dome; Antarctica; Siple Coast", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Fitzpatrick, Joan; Alley, Richard; Spencer, Matthew", "platforms": "Not provided; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND STATIONS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": null, "title": "Digital Imaging for Ice Core Analysis", "uid": "p0000011", "west": null}, {"awards": "9725305 Severinghaus, Jeffrey", "bounds_geometry": null, "dataset_titles": "Firn Air Isotope and Temperature Measurements from Siple Dome and South Pole", "datasets": [{"dataset_uid": "609098", "doi": "10.7265/N51N7Z2P", "keywords": "Antarctica; Atmosphere; Chemistry:Ice; Cryosphere; Geochemistry; Glaciology; Isotope; Paleoclimate; Siple Dome; Snow/Ice; South Pole; Temperature", "people": "Grachev, Alexi; Severinghaus, Jeffrey P.; Battle, Mark", "repository": "USAP-DC", "science_program": "Siple Dome Ice Core", "title": "Firn Air Isotope and Temperature Measurements from Siple Dome and South Pole", "url": "https://www.usap-dc.org/view/dataset/609098"}], "date_created": "Mon, 01 Jan 2001 00:00:00 GMT", "description": "9725305 Severinghaus This award supports a project to develop and apply a new technique for quantifying temperature changes in the past based on the thermodynamic principle of thermal diffusion, in which gas mixtures in a temperature gradient become fractionated. Air in polar firn is fractionated by temperature gradients induced by abrupt climate change, and a record of this air is preserved in bubbles in the ice. The magnitude of the abrupt temperature change, the precise relative timing, and an estimate of the absolute temperature change can be determined. By providing a gas-phase stratigraphic marker of temperature change, the phasing of methane (with decadal precision) and hence widespread climate change (relative to local polar temperature changes) can be determined (across five abrupt warming events during the last glacial period).", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e SAMPLERS \u003e BOTTLES/FLASKS/JARS \u003e FLASKS; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e THERMISTORS \u003e THERMISTORS", "is_usap_dc": true, "keywords": "Isotopic History; GROUND STATIONS; Thermal Fractionation; Thermal Diffusion; Polar Firn Air; Firn Temperature Measurements; Isotopic Anomalies; Xenon; Not provided; mass spectrometers; Atmospheric Gases; Argon Isotopes; Siple Dome; Krypton; Oxygen Isotopes; Trapped Air Bubbles; Nitrogen Isotopes; Seasonal Temperature Changes; Boreholes; Shallow Firn Air; Antarctica; Ice Core Gas Records; Firn Air Isotopes; Firn Air Isotope Measurements; South Pole; Seasonal Temperature Gradients; Firn Isotopes; Mass Spectrometry; GROUND-BASED OBSERVATIONS", "locations": "Antarctica; Siple Dome; South Pole", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Battle, Mark; Grachev, Alexi; Severinghaus, Jeffrey P.", "platforms": "LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND STATIONS; Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": null, "title": "Thermal Fractionation of Firn Air and the Ice Core Record of Abrupt Interstadial Climate Change", "uid": "p0000160", "west": null}]

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