[{"awards": "1149085 Bassis, Jeremy", "bounds_geometry": "POLYGON((66 -68,66.9 -68,67.8 -68,68.7 -68,69.6 -68,70.5 -68,71.4 -68,72.3 -68,73.2 -68,74.1 -68,75 -68,75 -68.6,75 -69.2,75 -69.8,75 -70.4,75 -71,75 -71.6,75 -72.2,75 -72.8,75 -73.4,75 -74,74.1 -74,73.2 -74,72.3 -74,71.4 -74,70.5 -74,69.6 -74,68.7 -74,67.8 -74,66.9 -74,66 -74,66 -73.4,66 -72.8,66 -72.2,66 -71.6,66 -71,66 -70.4,66 -69.8,66 -69.2,66 -68.6,66 -68))", "dataset_titles": "Antarctic Ice Shelf Rift Propagation Rates", "datasets": [{"dataset_uid": "601740", "doi": "10.15784/601740", "keywords": "Amery Ice Shelf; Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Shelf; MODIS", "people": "Bassis, Jeremy; Walker, Catherine", "repository": "USAP-DC", "science_program": null, "title": "Antarctic Ice Shelf Rift Propagation Rates", "url": "https://www.usap-dc.org/view/dataset/601740"}], "date_created": "Fri, 13 Oct 2023 00:00:00 GMT", "description": "This CAREER award supports a project to develop physically based bounds on the amount ice sheets can contribute to sea level rise in the coming centuries. To simulate these limits, a three-dimensional discrete element model will be developed and applied to simulate regions of interest in the Greenland and Antarctic ice sheets. These regions will include Helheim Glacier, Jakobshavn Isbr\u00e4e, Pine Island Glacier and sections of the Larsen Ice Shelf. In the discrete element model the ice will be discretized into distinct blocks or boulders of ice that interact through inelastic collisions, frictional forces and bonds. The spectrum of best to worst case scenarios will be examined by varying the strength and number of bonds between neighboring blocks of ice. The worst case scenario corresponds to completely disarticulated ice that behaves in a manner akin to a granular material while the best case scenario corresponds to completely intact ice with no preexisting flaws or fractures. Results from the discrete element model will be compared with those from analogous continuum models that incorporate a plastic yield stress into the more traditional viscous flow approximations used to simulate ice sheets. This will be done to assess if a fracture permitting plastic rheology can be efficiently incorporated into large-scale ice sheet models to simulate the evolution of ice sheets over the coming centuries. This award will also support to forge a partnership with two science teachers in the Ypsilanti school district in southeastern Michigan. The Ypsilanti school district is a low income, resource- poor region with a population that consists of ~70% underrepresented minorities and ~69% of students qualify for a free or reduced cost lunch. The cornerstone of the proposed partnership is the development of lesson plans and content associated with a hands-on ice sheet dynamics activity for 6th and 7th grade science students. The activity will be designed so that it integrates into existing classroom lesson plans and is aligned with State of Michigan Science Technology, Engineering and Math (STEM) curriculum goals. The aim of this program is to not only influence the elementary school students, but also to educate the teachers to extend the impact of the partnership beyond the duration of this study. Graduate students will be mentored and engaged in outreach activities and assist in supervising undergraduate students. Undergraduates will play a key role in developing an experimental, analogue ice dynamics lab designed to illustrate how ice sheets and glaciers flow and allow experimental validation of the proposed research activities. The research program advances ice sheet modeling infrastructure by distributing results through the community based Community Ice Sheet Model.", "east": 75.0, "geometry": "POINT(70.5 -71)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIERS/ICE SHEETS; Amery Ice Shelf", "locations": "Amery Ice Shelf", "north": -68.0, "nsf_funding_programs": "Antarctic Glaciology; Arctic Natural Sciences", "paleo_time": null, "persons": "Bassis, Jeremy", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -74.0, "title": "CAREER: Bound to Improve - Improved Estimates of the Glaciological Contribution to Sea Level Rise", "uid": "p0010437", "west": 66.0}, {"awards": "2021699 Trusel, Luke", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": "Antarctic ice sheet daily surface melt detection from ASCAT (2007-2022); ASCAT-ERA5 Antarctic Peninsula Daily Surface Meltwater Production (2007-2022); Trusel et al 2022, Geophysical Research Letters: Publication data and code", "datasets": [{"dataset_uid": "200363", "doi": "10.5281/zenodo.6374343", "keywords": null, "people": null, "repository": "Zenodo", "science_program": null, "title": "Trusel et al 2022, Geophysical Research Letters: Publication data and code", "url": "https://zenodo.org/record/6374343"}, {"dataset_uid": "200362", "doi": "10.5281/zenodo.7995543", "keywords": null, "people": null, "repository": "Zenodo", "science_program": null, "title": "ASCAT-ERA5 Antarctic Peninsula Daily Surface Meltwater Production (2007-2022)", "url": "https://zenodo.org/record/7995543"}, {"dataset_uid": "200364", "doi": "10.5281/zenodo.7995998", "keywords": null, "people": null, "repository": "Zenodo", "science_program": null, "title": "Antarctic ice sheet daily surface melt detection from ASCAT (2007-2022)", "url": "https://zenodo.org/record/7995998"}], "date_created": "Fri, 02 Jun 2023 00:00:00 GMT", "description": "Melting of snow and ice at the surface of the Antarctic ice sheet can lead to the formation of meltwater lakes, an important precursor to ice-shelf collapse and accelerated ice-sheet mass loss. Understanding the present state of Antarctic surface melt provides a baseline to gauge how quickly melt impacts could evolve in the future and to reduce uncertainties in estimates of future sea-level rise. \r\n\r\nThis project used a suite of complimentary measurements from Earth-observing satellites, ground observations, and numerical climate models to enhance understanding of surface melt and lakes, as well as the processes linking these systems. The project supported the scientific training of a postdoctoral associate, a graduate student, and several undergraduate researchers. In addition, the project aimed to promote public scientific literacy and the broadening of quantitative skills for high-school students through the development and implementation of an educational unit in a partnership with an education and outreach expert and two high school teachers.\r\n\r\nWe identified that surface lake drainages on East Antarctica\u2019s Amery Ice Shelf closely correspond to peaks in the daily amplitude of ocean tides. This research indicates that tidal-induced flexure inherent to the ice shelf grounding zone when combined with sufficient surface meltwater volumes can trigger ice shelf surface lake drainages (Trusel et al., 2022). In addition, we developed new estimates of surface melting across the Antarctic ice sheet using satellite and reanalysis data. First, we developed and implemented a pan-Antarctic ice sheet surface melt detection method applied to C-band Advanced Scatterometer (ASCAT) radar backscatter data. These binary melt presence/absence data were then combined with radar backscatter and ERA5 reanalysis outputs to estimate daily rates of surface meltwater production (in mm of water equivalence) across the Antarctic Peninsula region. These data therefore provide a new, observationally based dataset to investigate the intensity and drivers of surface melting in Antarctica\u2019s highest-melt region, and with which to evaluate climate model simulations. This method and an assessment of the resulting data are the subject of a forthcoming manuscript. \r\n\r\n", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "ICE SHEETS; Antarctica; Surface Hydrology", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Trusel, Luke; Moussavi, Mahsa", "platforms": null, "repo": "Zenodo", "repositories": "Zenodo", "science_programs": null, "south": -90.0, "title": "Collaborative Research: Water on the Antarctic Ice Sheet: Quantifying Surface Melt and Mapping Supraglacial Lakes", "uid": "p0010422", "west": -180.0}, {"awards": "1933764 Enderlin, Ellyn; 1643455 Enderlin, Ellyn", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": "Crane Glacier centerline observations and modeling results ; Remotely-sensed iceberg geometries and meltwater fluxes", "datasets": [{"dataset_uid": "601617", "doi": "10.15784/601617", "keywords": "Antarctica; Antarctic Peninsula; Crane Glacier; Glacier Dynamics; Glacier Mass Discharge; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Modeling; Model Output", "people": "Meehan, Tate; Enderlin, Ellyn; Aberle, Rainey; Marshall, Hans-Peter; Kopera, Michal", "repository": "USAP-DC", "science_program": null, "title": "Crane Glacier centerline observations and modeling results ", "url": "https://www.usap-dc.org/view/dataset/601617"}, {"dataset_uid": "601679", "doi": "10.15784/601679", "keywords": "Antarctica; Elevation; Glaciology; Iceberg; Meltwater; Submarine Melt", "people": "Dickson, Adam; Miller, Emily; Dryak, Mariama; Aberle, Rainey; Oliver, Caitlin; Enderlin, Ellyn", "repository": "USAP-DC", "science_program": null, "title": "Remotely-sensed iceberg geometries and meltwater fluxes", "url": "https://www.usap-dc.org/view/dataset/601679"}], "date_created": "Mon, 28 Jun 2021 00:00:00 GMT", "description": "The project uses repeat, very high-resolution (~0.5 m pixel width and length) satellite images acquired by the WorldView satellites, to estimate rates of iceberg melting in key coastal regions around Antarctica. The satellite images are used to construct maps of iceberg surface elevation change over time, which are converted to estimates of area-averaged submarine melt rates. Where ocean temperature observations are available, the melt rates are compared to these data to determine if variations in ocean temperature can explain observed iceberg melt variability. The iceberg melt rates are also compared to glacier frontal ablation rates (flow towards the terminus minus changes in terminus position over time) and integrated into a numerical ice flow model in order to assess the importance of submarine melting on recent changes in terminus position, ice flow, and dynamic mass loss. Overall, the analysis will yield insights into the effects of changes in ocean forcing on the submarine melting of Antarctic ice shelves and icebergs. The project does not require field work in Antarctica.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "Amery Ice Shelf; FIELD SURVEYS; Totten Glacier; GLACIER MASS BALANCE/ICE SHEET MASS BALANCE; USAP-DC; Antarctic Peninsula; ICEBERGS; Mertz Glacier; OCEAN TEMPERATURE; USA/NSF; Amd/Us; Amundsen Sea; Ronne Ice Shelf; Filchner Ice Shelf; AMD", "locations": "Antarctic Peninsula; Totten Glacier; Ronne Ice Shelf; Filchner Ice Shelf; Amery Ice Shelf; Mertz Glacier; Amundsen Sea", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Enderlin, Ellyn", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Antarctic Submarine Melt Variability from Remote Sensing of Icebergs", "uid": "p0010210", "west": -180.0}, {"awards": "1246378 Shevenell, Amelia", "bounds_geometry": "POLYGON((70 -68,70.5 -68,71 -68,71.5 -68,72 -68,72.5 -68,73 -68,73.5 -68,74 -68,74.5 -68,75 -68,75 -68.2,75 -68.4,75 -68.6,75 -68.8,75 -69,75 -69.2,75 -69.4,75 -69.6,75 -69.8,75 -70,74.5 -70,74 -70,73.5 -70,73 -70,72.5 -70,72 -70,71.5 -70,71 -70,70.5 -70,70 -70,70 -69.8,70 -69.6,70 -69.4,70 -69.2,70 -69,70 -68.8,70 -68.6,70 -68.4,70 -68.2,70 -68))", "dataset_titles": "Anvers Trough Foraminifer Stable Isotope data; Geochemical and sedimentologic data from NBP01-01 JPC-34", "datasets": [{"dataset_uid": "601180", "doi": "10.15784/601180", "keywords": "Antarctica; Be-10; Glaciers/ice Sheet; Glaciers/Ice Sheet; Grain Size; Late Quaternary; Magnetic Susceptibility; Mass Spectrometry; NBP0101; Paleoenvironment; Prydz Bay; Radiocarbon; R/v Nathaniel B. Palmer; Sediment; Sediment Core; Sediment Core Data", "people": "Shevenell, Amelia", "repository": "USAP-DC", "science_program": null, "title": "Geochemical and sedimentologic data from NBP01-01 JPC-34", "url": "https://www.usap-dc.org/view/dataset/601180"}, {"dataset_uid": "601064", "doi": "10.15784/601064", "keywords": "Antarctica; Antarctic Peninsula; Anvers Trough; Chemistry:sediment; Chemistry:Sediment; Foraminifera; Geochemistry; Isotope; LMG1211; LMG1311; Marine Sediments; Oceans; Paleoclimate; Sample/collection Description; Sample/Collection Description; Southern Ocean", "people": "Shevenell, Amelia", "repository": "USAP-DC", "science_program": null, "title": "Anvers Trough Foraminifer Stable Isotope data", "url": "https://www.usap-dc.org/view/dataset/601064"}], "date_created": "Fri, 27 Oct 2017 00:00:00 GMT", "description": "Intellectual Merit: \u003cbr/\u003eSouthern Ocean processes play an important role in Late Quaternary glacial-interglacial climate change. However, the direct influence of newly upwelled warm nutrient-rich Circumpolar Deep Water on the Antarctic cryosphere remains speculative. The PI proposes to test the hypothesis that Circumpolar Deep Water-derived ocean heat negatively impacts the mass-balance of Antarctica?s ice sheets during deglaciations using precisely dated late Quaternary paleoceanographic studies of Antarctic margin sediments and a suite of geochemical proxies measured on three existing glacial marine sediment cores from the Prydz Channel, Antarctica. Specifically, the PI will use these data to reconstruct the Late Quaternary history of the Lambert Glacier/Amery Ice Shelf system; evaluate the timing, speed, and style of retreat of the Lambert Glacier/Amery Ice Shelf system during the last deglaciation, and to assess the impact of Circumpolar Deep Water intrusions on the Lambert Glacier/Amery Ice Shelf system in the Late Quaternary. Diatom bound radiocarbon and optically stimulated luminescence techniques will be used to obtain precise stratigraphic age control for the Prydz Channel siliceous muddy ooze intervals. In addition, the PI will measure sedimentary 10Be concentrations to determine the origin of the siliceous muddy ooze units and to track past changes in the position of the ice shelf front.\u003cbr/\u003e\u003cbr/\u003eBroader impacts: \u003cbr/\u003eThis proposal will support an early career female scientist and will provide professional development and research experiences for women/minority graduate and undergraduate students. The PI will take advantage of USF?s Oceanography Camp for Girls.", "east": 75.0, "geometry": "POINT(72.5 -69)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e SEDIMENT CORERS", "is_usap_dc": true, "keywords": "Amd/Us; R/V NBP; USAP-DC", "locations": null, "north": -68.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Shevenell, Amelia", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -70.0, "title": "Late Quaternary Evolution of the Lambert Glacier/Amery Ice Shelf System, Prydz Bay, Antarctica", "uid": "p0000381", "west": 70.0}, {"awards": "1246378 Shevenell, Amelia", "bounds_geometry": "POLYGON((-65.32 -64.15,-65.309 -64.15,-65.298 -64.15,-65.287 -64.15,-65.276 -64.15,-65.265 -64.15,-65.254 -64.15,-65.243 -64.15,-65.232 -64.15,-65.221 -64.15,-65.21 -64.15,-65.21 -64.186,-65.21 -64.222,-65.21 -64.258,-65.21 -64.294,-65.21 -64.33,-65.21 -64.366,-65.21 -64.402,-65.21 -64.438,-65.21 -64.474,-65.21 -64.51,-65.221 -64.51,-65.232 -64.51,-65.243 -64.51,-65.254 -64.51,-65.265 -64.51,-65.276 -64.51,-65.287 -64.51,-65.298 -64.51,-65.309 -64.51,-65.32 -64.51,-65.32 -64.474,-65.32 -64.438,-65.32 -64.402,-65.32 -64.366,-65.32 -64.33,-65.32 -64.294,-65.32 -64.258,-65.32 -64.222,-65.32 -64.186,-65.32 -64.15))", "dataset_titles": "Anvers Trough Foraminifer Stable Isotope data; Geochemical and sedimentologic data from NBP01-01 JPC-34", "datasets": [{"dataset_uid": "601180", "doi": "10.15784/601180", "keywords": "Antarctica; Be-10; Glaciers/ice Sheet; Glaciers/Ice Sheet; Grain Size; Late Quaternary; Magnetic Susceptibility; Mass Spectrometry; NBP0101; Paleoenvironment; Prydz Bay; Radiocarbon; R/v Nathaniel B. Palmer; Sediment; Sediment Core; Sediment Core Data", "people": "Shevenell, Amelia", "repository": "USAP-DC", "science_program": null, "title": "Geochemical and sedimentologic data from NBP01-01 JPC-34", "url": "https://www.usap-dc.org/view/dataset/601180"}, {"dataset_uid": "601064", "doi": "10.15784/601064", "keywords": "Antarctica; Antarctic Peninsula; Anvers Trough; Chemistry:sediment; Chemistry:Sediment; Foraminifera; Geochemistry; Isotope; LMG1211; LMG1311; Marine Sediments; Oceans; Paleoclimate; Sample/collection Description; Sample/Collection Description; Southern Ocean", "people": "Shevenell, Amelia", "repository": "USAP-DC", "science_program": null, "title": "Anvers Trough Foraminifer Stable Isotope data", "url": "https://www.usap-dc.org/view/dataset/601064"}], "date_created": "Fri, 27 Oct 2017 00:00:00 GMT", "description": "Intellectual Merit: \u003cbr/\u003eSouthern Ocean processes play an important role in Late Quaternary glacial-interglacial climate change. However, the direct influence of newly upwelled warm nutrient-rich Circumpolar Deep Water on the Antarctic cryosphere remains speculative. The PI proposes to test the hypothesis that Circumpolar Deep Water-derived ocean heat negatively impacts the mass-balance of Antarctica?s ice sheets during deglaciations using precisely dated late Quaternary paleoceanographic studies of Antarctic margin sediments and a suite of geochemical proxies measured on three existing glacial marine sediment cores from the Prydz Channel, Antarctica. Specifically, the PI will use these data to reconstruct the Late Quaternary history of the Lambert Glacier/Amery Ice Shelf system; evaluate the timing, speed, and style of retreat of the Lambert Glacier/Amery Ice Shelf system during the last deglaciation, and to assess the impact of Circumpolar Deep Water intrusions on the Lambert Glacier/Amery Ice Shelf system in the Late Quaternary. Diatom bound radiocarbon and optically stimulated luminescence techniques will be used to obtain precise stratigraphic age control for the Prydz Channel siliceous muddy ooze intervals. In addition, the PI will measure sedimentary 10Be concentrations to determine the origin of the siliceous muddy ooze units and to track past changes in the position of the ice shelf front.\u003cbr/\u003e\u003cbr/\u003eBroader impacts: \u003cbr/\u003eThis proposal will support an early career female scientist and will provide professional development and research experiences for women/minority graduate and undergraduate students. The PI will take advantage of USF?s Oceanography Camp for Girls.", "east": -65.21, "geometry": "POINT(-65.265 -64.33)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e SEDIMENT CORERS", "is_usap_dc": true, "keywords": "Amd/Us; R/V NBP; USAP-DC", "locations": null, "north": -64.15, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Shevenell, Amelia", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -64.51, "title": "Late Quaternary Evolution of the Lambert Glacier/Amery Ice Shelf System, Prydz Bay, Antarctica", "uid": "p0000381", "west": -65.32}, {"awards": "1443444 Yuan, Xiaojun", "bounds_geometry": "POLYGON((65.4503 -63.5143,67.2063 -63.5143,68.9623 -63.5143,70.7183 -63.5143,72.4743 -63.5143,74.2303 -63.5143,75.9863 -63.5143,77.7423 -63.5143,79.4983 -63.5143,81.2543 -63.5143,83.0103 -63.5143,83.0103 -64.09423,83.0103 -64.67416,83.0103 -65.25409,83.0103 -65.83402,83.0103 -66.41395,83.0103 -66.99388,83.0103 -67.57381,83.0103 -68.15374,83.0103 -68.73367,83.0103 -69.3136,81.2543 -69.3136,79.4983 -69.3136,77.7423 -69.3136,75.9863 -69.3136,74.2303 -69.3136,72.4743 -69.3136,70.7183 -69.3136,68.9623 -69.3136,67.2063 -69.3136,65.4503 -69.3136,65.4503 -68.73367,65.4503 -68.15374,65.4503 -67.57381,65.4503 -66.99388,65.4503 -66.41395,65.4503 -65.83402,65.4503 -65.25409,65.4503 -64.67416,65.4503 -64.09423,65.4503 -63.5143))", "dataset_titles": "CTD Data Acquired by R/V Xue Long in the Prydz Bay- Amery Ice Shelf Region, 2015-2017", "datasets": [{"dataset_uid": "600174", "doi": "10.15784/600174", "keywords": "CTD Data; Oceans; Physical Oceanography; Prydz Bay; Sample/collection Description; Sample/Collection Description; Southern Ocean; Xue Long", "people": "Yuan, Xiaojun", "repository": "USAP-DC", "science_program": null, "title": "CTD Data Acquired by R/V Xue Long in the Prydz Bay- Amery Ice Shelf Region, 2015-2017", "url": "https://www.usap-dc.org/view/dataset/600174"}], "date_created": "Tue, 20 Jun 2017 00:00:00 GMT", "description": "Antarctic Bottom Water (AABW) formation is a key component in setting the global thermohaline (overturning) circulation. Recent studies infer a reduction of the AABW component from reduced volume of AABW entering global deep ocean basins around the Antarctic continent. It is important to obtain better estimates of AABW production rate in its source areas, and to investigate whether the global overturning circulation is slowing-down. The project will continue fieldwork with CTD/LADCP surveys including 2 yearly repeat sections, mooring recoveries and deployments. Seasonal-interannual variability of CDW intrusion, dense shelf water accumulation and export as well as overflow from the Prydz Bay shelf will also be observed. The Prydz Bay- Amery Ice Shelf region has been suggested as a key AABW production site. USAP access to this remote region of the Antarctic continent is challenging. The project will involve fieldwork to be carried out with Danish and Chinese collaboration aboard the Chinese research vessel, Xue Long. A high-resolution regional ocean-sea ice coupled model will be developed to allow time and space continuous three-dimensional ocean state estimation. Both in-situ and remote sensing observations along with the modeling simulation results will be used to investigate (i) the local atmosphere-ocean-sea ice interaction and shelf processes that produce dense shelf water and (ii) the dynamic processes that control the shelf water export.", "east": 83.0103, "geometry": "POINT(74.2303 -66.41395)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -63.5143, "nsf_funding_programs": "Antarctic Ocean and Atmospheric Sciences", "paleo_time": null, "persons": "Yuan, Xiaojun", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -69.3136, "title": "Collaborative Research: Contribution of Prydz Bay Shelf Water to Antarctic Bottom Water Formation", "uid": "p0000295", "west": 65.4503}, {"awards": "0739769 Fricker, Helen", "bounds_geometry": "POLYGON((-57.22 74.58,-55.343 74.58,-53.466 74.58,-51.589 74.58,-49.712 74.58,-47.835 74.58,-45.958 74.58,-44.081 74.58,-42.204 74.58,-40.327 74.58,-38.45 74.58,-38.45 73.822,-38.45 73.064,-38.45 72.306,-38.45 71.548,-38.45 70.79,-38.45 70.032,-38.45 69.274,-38.45 68.516,-38.45 67.758,-38.45 67,-40.327 67,-42.204 67,-44.081 67,-45.958 67,-47.835 67,-49.712 67,-51.589 67,-53.466 67,-55.343 67,-57.22 67,-57.22 67.758,-57.22 68.516,-57.22 69.274,-57.22 70.032,-57.22 70.79,-57.22 71.548,-57.22 72.306,-57.22 73.064,-57.22 73.822,-57.22 74.58))", "dataset_titles": "Amery Ice Shelf metadata (IRIS); Columbia Glacier metadata (IRIS); Greenland Ice Sheet Seismic Network metadata (IRIS)", "datasets": [{"dataset_uid": "000100", "doi": "", "keywords": null, "people": null, "repository": "IRIS", "science_program": null, "title": "Amery Ice Shelf metadata (IRIS)", "url": "http://www.iris.edu/mda/X9?timewindow=2004-2007"}, {"dataset_uid": "000101", "doi": "", "keywords": null, "people": null, "repository": "IRIS", "science_program": null, "title": "Columbia Glacier metadata (IRIS)", "url": "http://www.iris.edu/mda/YM?timewindow=2004-2005"}, {"dataset_uid": "000103", "doi": "", "keywords": null, "people": null, "repository": "IRIS", "science_program": null, "title": "Greenland Ice Sheet Seismic Network metadata (IRIS)", "url": "http://www.iris.edu/mda/_GLISN"}], "date_created": "Thu, 22 Mar 2012 00:00:00 GMT", "description": "This award supports a project to strengthen collaborations between the various research groups working on iceberg calving. Relatively little is known about the calving process, especially the physics that governs the initiation and propagation of fractures within the ice. This knowledge gap exists in part because of the diverse range in spatial and temporal scales associated with calving (ranging from less than one meter to over a hundred kilometers in length scale). It is becoming increasingly clear that to predict the future behavior of the Antarctic Ice Sheet and its contribution to sea level rise, it is necessary to improve our understanding of iceberg calving processes. Further challenges stem from difficulties in monitoring and quantifying short-time and spatial-scale processes associated with ice fracture, including increased fracturing events in ice shelves or outlet glaciers that may be a precursor to disintegration, retreat or increased calving rates. Coupled, these fundamental problems currently prohibit the inclusion of iceberg calving into numerical ice sheet models and hinder our ability to accurately forecast changes in sea level in response to climate change. Seismic data from four markedly different environmental regimes forms the basis of the proposed research, and researchers most familiar with the datasets will perform all analyses. Extracting the similarities and differences across the full breadth of calving processes embodies the core of the proposed work, combining and improving methods previously developed by each group. Techniques derived from solid Earth seismology, including waveform cross-correlation and clustering will be applied to each data set allowing quantitative process comparisons on a significantly higher level than previously possible. This project will derive catalogues of glaciologically produced seismic events; the events will then be located and categorized based on their location, waveform and waveform spectra both within individual environments and between regions. The intellectual merit of this work is that it will lead to a better understanding of iceberg calving and the teleconnections between seismic events and other geophysical processes around the globe. The broader impacts of this work are that it relates directly to socio-environmental impacts of global change and sea level rise. Strong collaborations will form as a result of this research, including bolstered collaborations between the glacier and ice sheet communities, as well as the glaciology and seismology communities. Outreach and public dissemination of findings will be driven by SIO\u0027s Visualization Center, and Birch Aquarium, hosting presentations devoted to the role of the cryosphere in global change. Time-lapse movies of recent changes at Columbia Glacier will be used to engage potential young scientists. A program of presentations outside the university setting to at-risk and gifted youth will be continued. This study will also involve undergraduates in analyses and interpretation and presentation of the seismic data assembled. The work will also support two junior scientists who will be supported by this project.", "east": 72.949097, "geometry": "POINT(72.8836975 -69.008701)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e SEISMOMETERS \u003e SEISMOMETERS", "is_usap_dc": false, "keywords": "PASSCAL; Not provided; Antarctic; SEISMOLOGICAL STATIONS; Iceberg; Seismology; Calving", "locations": "Antarctic", "north": -68.993301, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Fricker, Helen", "platforms": "LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e PASSCAL; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e SEISMOLOGICAL STATIONS; Not provided", "repo": "IRIS", "repositories": "IRIS", "science_programs": null, "south": -69.024101, "title": "An Investigation into the Seismic Signatures Generated by Iceberg Calving and Rifting", "uid": "p0000683", "west": 72.818298}, {"awards": "0337838 Fricker, Helen", "bounds_geometry": "POINT(71 -69.75)", "dataset_titles": "Access to data", "datasets": [{"dataset_uid": "001537", "doi": "", "keywords": null, "people": null, "repository": "IRIS", "science_program": null, "title": "Access to data", "url": "http://www.iris.edu/data/data.htm"}], "date_created": "Fri, 27 Apr 2007 00:00:00 GMT", "description": "This award supports a comprehensive study of rift growth on the Amery Ice Shelf (AIS), East Antarctica, using a combination of in situ and remote sensing data with numerical modeling. On the AIS there is an opportunity to examine an active rift system, which is a combination of two longitudinal-to-flow rifts, which originated at the ice shelf front in the suture zones between merging flowbands, and two transverse-to-flow rifts, which formed at the tip of the western longitudinal rift around 1996. Work in progress indicates that these two transverse rifts do not propagate independently of each other, but somehow grow more or less synchronously. The longest of these rifts-the eastern one-grows at an average rate of about 8m per day. When it meets the eastern longitudinal rift, an event that is expected to occur during the funding period (mid-2006), an iceberg (~30 x 30 km) will calve. Based on observations collected over the past half century, there is reason to believe that such a calving event may be a part of a repetitive sequence. In the proposed project, the expansion and propagation of both transverse rifts will be studied using a network of GPS and seismometers deployed around the tip of each transverse rift. Once the iceberg has calved, the effects its calving has on the dynamics of the ice shelf and the activation of previously inactive rifts will also be studied. Insofar as the rate of calving activity is a proxy for local and regional climate conditions, a broader impact of the proposed work is directly related to the socio-environmental topics of climate and sea-level change. The subject of iceberg calving has a history of sparking a great deal of interest from the media and the public alike, especially since the recent large calving events from the Ross and Ronne ice shelves and the remarkably sudden break-up of the Larsen Ice Shelf. The work will involve at least one graduate student, and will involve a partnership with a local charter high school. Field work, instrument deployments, and data collection and analysis will be conducted in close collaboration with the Australian Antarctic Division and the University of Tasmania, which has been a crucial component of research conducted to date. This project will also make use of the Scripps Institution of Oceanography Visualization Center as a means to display results to faculty and researchers of the University of California, San Diego, undergraduate and graduate students, to school children and their teachers, and ultimately to the visiting public.", "east": 71.0, "geometry": "POINT(71 -69.75)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e SEISMOMETERS \u003e SEISMOMETERS", "is_usap_dc": false, "keywords": "Not provided; Geodesy; Seismic", "locations": null, "north": -69.75, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Fricker, Helen; Minster, Jean-Bernard", "platforms": "Not provided", "repo": "IRIS", "repositories": "IRIS", "science_programs": null, "south": -69.75, "title": "Monitoring an Active Rift System at the Front of Amery Ice Shelf, East Antarctica", "uid": "p0000668", "west": 71.0}, {"awards": "0126149 Liu, Hongxing", "bounds_geometry": null, "dataset_titles": "Access to Antarctic coastline coverage and reference documents; Access to Antarctic snow zone coverage and reference documents; Access to boundary file and reference documents; Access to ice velocity data and reference documents; Access to snow melt extent image files and reference documents", "datasets": [{"dataset_uid": "001352", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Access to Antarctic snow zone coverage and reference documents", "url": "http://geog.tamu.edu/~liu/research/download.htm"}, {"dataset_uid": "001779", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Access to ice velocity data and reference documents", "url": "http://geog.tamu.edu/~liu/research/download.htm"}, {"dataset_uid": "001640", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Access to snow melt extent image files and reference documents", "url": "http://geog.tamu.edu/~liu/research/download.htm"}, {"dataset_uid": "001350", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Access to boundary file and reference documents", "url": "http://geog.tamu.edu/~liu/research/download.htm"}, {"dataset_uid": "001351", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Access to Antarctic coastline coverage and reference documents", "url": "http://geog.tamu.edu/~liu/research/download.htm"}], "date_created": "Tue, 15 Aug 2006 00:00:00 GMT", "description": "This award supports a project to characterize the morphology, ice motion velocity and mass balance of Lambert Glacier, Antarctica using state-of-the-art remote sensing and GIS techniques. Lambert Glacier is the largest ice stream in the world. Because of its size, it plays a fundamental role in the study of glacial dynamics and mass budget in response to present and future climate changes. Along with the bedrock topography and ice thickness data derived from airborne radio echo soundings and snow accumulation data compiled from ground-based measurements, the dynamic behavior and mass balance of the Lambert glacial basin in a Geographic Information Systems (GIS) environment will be examined. Specific objectives are to: (1) Extract two-dimensional ice velocity field over the entire Lambert glacial basin using speckle matching and differential interferometric SAR (InSAR) techniques, and produce a full coverage of radar coherence map over the drainage basin. With the ice velocity data, calculate the strain rate field from the initiation areas of the ice stream onto the Amery Ice Shelf; (2) Derive high-resolution digital elevation model (DEM) over the Lambert glacial drainage basin using SAR stereo, differential interferometric SAR, and GLAS laser altimetry techniques. Based on the DEM, extract ice divides and ice flow directions, delineate the snow catchment basin, and calculate the balance deformation velocity and the basal shear stress; (3) Interpolate traverse ice thickness data collected by Australian and Russian airborne radio echo sounding surveys into a regular grid, and derive a regular grid of bedrock topography in combination with the DEM; (4) Integrate newly derived ice velocity and ice thickness data as well as snow accumulation rate data compiled from previous ground-based measurements into a geographic information system (GIS), and calculate the mass flux through the ice stream at the grounding lines and net mass balance throughout the drainage basin. With these new measurements and calculations derived from advanced remote sensing techniques, we will be able to improve our understanding of dynamic behavior and current mass balance status of the Lambert glacial basin, gain an insight on the relationship between ice mass change and the variation in regional and global climate at decadal scale, and provide an evaluation on the issue of whether the Lambert glacier basin is subject to surging in the context of future climate change.", "east": null, "geometry": null, "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e SPECTROMETERS/RADIOMETERS \u003e IMAGING SPECTROMETERS/RADIOMETERS \u003e SMMR; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e SPECTROMETERS/RADIOMETERS \u003e IMAGING SPECTROMETERS/RADIOMETERS \u003e SSM/I; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e IMAGING RADARS \u003e IFSAR; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e IMAGING RADARS \u003e SAR", "is_usap_dc": false, "keywords": "DEM; Not provided; RADARSAT-1", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Liu, Hongxing; Jezek, Kenneth", "platforms": "Not provided; OTHER \u003e MODELS \u003e DEM; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e RADARSAT \u003e RADARSAT-1", "repo": "PI website", "repositories": "PI website", "science_programs": null, "south": null, "title": "High-Resolution Modeling of Surface Topography, Ice Motion, and Mass Balance in the Lambert Glacial Basin using Radar Remote Sensing and GIS Techniques", "uid": "p0000204", "west": null}]
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This CAREER award supports a project to develop physically based bounds on the amount ice sheets can contribute to sea level rise in the coming centuries. To simulate these limits, a three-dimensional discrete element model will be developed and applied to simulate regions of interest in the Greenland and Antarctic ice sheets. These regions will include Helheim Glacier, Jakobshavn Isbräe, Pine Island Glacier and sections of the Larsen Ice Shelf. In the discrete element model the ice will be discretized into distinct blocks or boulders of ice that interact through inelastic collisions, frictional forces and bonds. The spectrum of best to worst case scenarios will be examined by varying the strength and number of bonds between neighboring blocks of ice. The worst case scenario corresponds to completely disarticulated ice that behaves in a manner akin to a granular material while the best case scenario corresponds to completely intact ice with no preexisting flaws or fractures. Results from the discrete element model will be compared with those from analogous continuum models that incorporate a plastic yield stress into the more traditional viscous flow approximations used to simulate ice sheets. This will be done to assess if a fracture permitting plastic rheology can be efficiently incorporated into large-scale ice sheet models to simulate the evolution of ice sheets over the coming centuries. This award will also support to forge a partnership with two science teachers in the Ypsilanti school district in southeastern Michigan. The Ypsilanti school district is a low income, resource- poor region with a population that consists of ~70% underrepresented minorities and ~69% of students qualify for a free or reduced cost lunch. The cornerstone of the proposed partnership is the development of lesson plans and content associated with a hands-on ice sheet dynamics activity for 6th and 7th grade science students. The activity will be designed so that it integrates into existing classroom lesson plans and is aligned with State of Michigan Science Technology, Engineering and Math (STEM) curriculum goals. The aim of this program is to not only influence the elementary school students, but also to educate the teachers to extend the impact of the partnership beyond the duration of this study. Graduate students will be mentored and engaged in outreach activities and assist in supervising undergraduate students. Undergraduates will play a key role in developing an experimental, analogue ice dynamics lab designed to illustrate how ice sheets and glaciers flow and allow experimental validation of the proposed research activities. The research program advances ice sheet modeling infrastructure by distributing results through the community based Community Ice Sheet Model.
Melting of snow and ice at the surface of the Antarctic ice sheet can lead to the formation of meltwater lakes, an important precursor to ice-shelf collapse and accelerated ice-sheet mass loss. Understanding the present state of Antarctic surface melt provides a baseline to gauge how quickly melt impacts could evolve in the future and to reduce uncertainties in estimates of future sea-level rise.
This project used a suite of complimentary measurements from Earth-observing satellites, ground observations, and numerical climate models to enhance understanding of surface melt and lakes, as well as the processes linking these systems. The project supported the scientific training of a postdoctoral associate, a graduate student, and several undergraduate researchers. In addition, the project aimed to promote public scientific literacy and the broadening of quantitative skills for high-school students through the development and implementation of an educational unit in a partnership with an education and outreach expert and two high school teachers.
We identified that surface lake drainages on East Antarctica’s Amery Ice Shelf closely correspond to peaks in the daily amplitude of ocean tides. This research indicates that tidal-induced flexure inherent to the ice shelf grounding zone when combined with sufficient surface meltwater volumes can trigger ice shelf surface lake drainages (Trusel et al., 2022). In addition, we developed new estimates of surface melting across the Antarctic ice sheet using satellite and reanalysis data. First, we developed and implemented a pan-Antarctic ice sheet surface melt detection method applied to C-band Advanced Scatterometer (ASCAT) radar backscatter data. These binary melt presence/absence data were then combined with radar backscatter and ERA5 reanalysis outputs to estimate daily rates of surface meltwater production (in mm of water equivalence) across the Antarctic Peninsula region. These data therefore provide a new, observationally based dataset to investigate the intensity and drivers of surface melting in Antarctica’s highest-melt region, and with which to evaluate climate model simulations. This method and an assessment of the resulting data are the subject of a forthcoming manuscript.
The project uses repeat, very high-resolution (~0.5 m pixel width and length) satellite images acquired by the WorldView satellites, to estimate rates of iceberg melting in key coastal regions around Antarctica. The satellite images are used to construct maps of iceberg surface elevation change over time, which are converted to estimates of area-averaged submarine melt rates. Where ocean temperature observations are available, the melt rates are compared to these data to determine if variations in ocean temperature can explain observed iceberg melt variability. The iceberg melt rates are also compared to glacier frontal ablation rates (flow towards the terminus minus changes in terminus position over time) and integrated into a numerical ice flow model in order to assess the importance of submarine melting on recent changes in terminus position, ice flow, and dynamic mass loss. Overall, the analysis will yield insights into the effects of changes in ocean forcing on the submarine melting of Antarctic ice shelves and icebergs. The project does not require field work in Antarctica.
Intellectual Merit: <br/>Southern Ocean processes play an important role in Late Quaternary glacial-interglacial climate change. However, the direct influence of newly upwelled warm nutrient-rich Circumpolar Deep Water on the Antarctic cryosphere remains speculative. The PI proposes to test the hypothesis that Circumpolar Deep Water-derived ocean heat negatively impacts the mass-balance of Antarctica?s ice sheets during deglaciations using precisely dated late Quaternary paleoceanographic studies of Antarctic margin sediments and a suite of geochemical proxies measured on three existing glacial marine sediment cores from the Prydz Channel, Antarctica. Specifically, the PI will use these data to reconstruct the Late Quaternary history of the Lambert Glacier/Amery Ice Shelf system; evaluate the timing, speed, and style of retreat of the Lambert Glacier/Amery Ice Shelf system during the last deglaciation, and to assess the impact of Circumpolar Deep Water intrusions on the Lambert Glacier/Amery Ice Shelf system in the Late Quaternary. Diatom bound radiocarbon and optically stimulated luminescence techniques will be used to obtain precise stratigraphic age control for the Prydz Channel siliceous muddy ooze intervals. In addition, the PI will measure sedimentary 10Be concentrations to determine the origin of the siliceous muddy ooze units and to track past changes in the position of the ice shelf front.<br/><br/>Broader impacts: <br/>This proposal will support an early career female scientist and will provide professional development and research experiences for women/minority graduate and undergraduate students. The PI will take advantage of USF?s Oceanography Camp for Girls.
Intellectual Merit: <br/>Southern Ocean processes play an important role in Late Quaternary glacial-interglacial climate change. However, the direct influence of newly upwelled warm nutrient-rich Circumpolar Deep Water on the Antarctic cryosphere remains speculative. The PI proposes to test the hypothesis that Circumpolar Deep Water-derived ocean heat negatively impacts the mass-balance of Antarctica?s ice sheets during deglaciations using precisely dated late Quaternary paleoceanographic studies of Antarctic margin sediments and a suite of geochemical proxies measured on three existing glacial marine sediment cores from the Prydz Channel, Antarctica. Specifically, the PI will use these data to reconstruct the Late Quaternary history of the Lambert Glacier/Amery Ice Shelf system; evaluate the timing, speed, and style of retreat of the Lambert Glacier/Amery Ice Shelf system during the last deglaciation, and to assess the impact of Circumpolar Deep Water intrusions on the Lambert Glacier/Amery Ice Shelf system in the Late Quaternary. Diatom bound radiocarbon and optically stimulated luminescence techniques will be used to obtain precise stratigraphic age control for the Prydz Channel siliceous muddy ooze intervals. In addition, the PI will measure sedimentary 10Be concentrations to determine the origin of the siliceous muddy ooze units and to track past changes in the position of the ice shelf front.<br/><br/>Broader impacts: <br/>This proposal will support an early career female scientist and will provide professional development and research experiences for women/minority graduate and undergraduate students. The PI will take advantage of USF?s Oceanography Camp for Girls.
Antarctic Bottom Water (AABW) formation is a key component in setting the global thermohaline (overturning) circulation. Recent studies infer a reduction of the AABW component from reduced volume of AABW entering global deep ocean basins around the Antarctic continent. It is important to obtain better estimates of AABW production rate in its source areas, and to investigate whether the global overturning circulation is slowing-down. The project will continue fieldwork with CTD/LADCP surveys including 2 yearly repeat sections, mooring recoveries and deployments. Seasonal-interannual variability of CDW intrusion, dense shelf water accumulation and export as well as overflow from the Prydz Bay shelf will also be observed. The Prydz Bay- Amery Ice Shelf region has been suggested as a key AABW production site. USAP access to this remote region of the Antarctic continent is challenging. The project will involve fieldwork to be carried out with Danish and Chinese collaboration aboard the Chinese research vessel, Xue Long. A high-resolution regional ocean-sea ice coupled model will be developed to allow time and space continuous three-dimensional ocean state estimation. Both in-situ and remote sensing observations along with the modeling simulation results will be used to investigate (i) the local atmosphere-ocean-sea ice interaction and shelf processes that produce dense shelf water and (ii) the dynamic processes that control the shelf water export.
This award supports a project to strengthen collaborations between the various research groups working on iceberg calving. Relatively little is known about the calving process, especially the physics that governs the initiation and propagation of fractures within the ice. This knowledge gap exists in part because of the diverse range in spatial and temporal scales associated with calving (ranging from less than one meter to over a hundred kilometers in length scale). It is becoming increasingly clear that to predict the future behavior of the Antarctic Ice Sheet and its contribution to sea level rise, it is necessary to improve our understanding of iceberg calving processes. Further challenges stem from difficulties in monitoring and quantifying short-time and spatial-scale processes associated with ice fracture, including increased fracturing events in ice shelves or outlet glaciers that may be a precursor to disintegration, retreat or increased calving rates. Coupled, these fundamental problems currently prohibit the inclusion of iceberg calving into numerical ice sheet models and hinder our ability to accurately forecast changes in sea level in response to climate change. Seismic data from four markedly different environmental regimes forms the basis of the proposed research, and researchers most familiar with the datasets will perform all analyses. Extracting the similarities and differences across the full breadth of calving processes embodies the core of the proposed work, combining and improving methods previously developed by each group. Techniques derived from solid Earth seismology, including waveform cross-correlation and clustering will be applied to each data set allowing quantitative process comparisons on a significantly higher level than previously possible. This project will derive catalogues of glaciologically produced seismic events; the events will then be located and categorized based on their location, waveform and waveform spectra both within individual environments and between regions. The intellectual merit of this work is that it will lead to a better understanding of iceberg calving and the teleconnections between seismic events and other geophysical processes around the globe. The broader impacts of this work are that it relates directly to socio-environmental impacts of global change and sea level rise. Strong collaborations will form as a result of this research, including bolstered collaborations between the glacier and ice sheet communities, as well as the glaciology and seismology communities. Outreach and public dissemination of findings will be driven by SIO's Visualization Center, and Birch Aquarium, hosting presentations devoted to the role of the cryosphere in global change. Time-lapse movies of recent changes at Columbia Glacier will be used to engage potential young scientists. A program of presentations outside the university setting to at-risk and gifted youth will be continued. This study will also involve undergraduates in analyses and interpretation and presentation of the seismic data assembled. The work will also support two junior scientists who will be supported by this project.
This award supports a comprehensive study of rift growth on the Amery Ice Shelf (AIS), East Antarctica, using a combination of in situ and remote sensing data with numerical modeling. On the AIS there is an opportunity to examine an active rift system, which is a combination of two longitudinal-to-flow rifts, which originated at the ice shelf front in the suture zones between merging flowbands, and two transverse-to-flow rifts, which formed at the tip of the western longitudinal rift around 1996. Work in progress indicates that these two transverse rifts do not propagate independently of each other, but somehow grow more or less synchronously. The longest of these rifts-the eastern one-grows at an average rate of about 8m per day. When it meets the eastern longitudinal rift, an event that is expected to occur during the funding period (mid-2006), an iceberg (~30 x 30 km) will calve. Based on observations collected over the past half century, there is reason to believe that such a calving event may be a part of a repetitive sequence. In the proposed project, the expansion and propagation of both transverse rifts will be studied using a network of GPS and seismometers deployed around the tip of each transverse rift. Once the iceberg has calved, the effects its calving has on the dynamics of the ice shelf and the activation of previously inactive rifts will also be studied. Insofar as the rate of calving activity is a proxy for local and regional climate conditions, a broader impact of the proposed work is directly related to the socio-environmental topics of climate and sea-level change. The subject of iceberg calving has a history of sparking a great deal of interest from the media and the public alike, especially since the recent large calving events from the Ross and Ronne ice shelves and the remarkably sudden break-up of the Larsen Ice Shelf. The work will involve at least one graduate student, and will involve a partnership with a local charter high school. Field work, instrument deployments, and data collection and analysis will be conducted in close collaboration with the Australian Antarctic Division and the University of Tasmania, which has been a crucial component of research conducted to date. This project will also make use of the Scripps Institution of Oceanography Visualization Center as a means to display results to faculty and researchers of the University of California, San Diego, undergraduate and graduate students, to school children and their teachers, and ultimately to the visiting public.
This award supports a project to characterize the morphology, ice motion velocity and mass balance of Lambert Glacier, Antarctica using state-of-the-art remote sensing and GIS techniques. Lambert Glacier is the largest ice stream in the world. Because of its size, it plays a fundamental role in the study of glacial dynamics and mass budget in response to present and future climate changes. Along with the bedrock topography and ice thickness data derived from airborne radio echo soundings and snow accumulation data compiled from ground-based measurements, the dynamic behavior and mass balance of the Lambert glacial basin in a Geographic Information Systems (GIS) environment will be examined. Specific objectives are to: (1) Extract two-dimensional ice velocity field over the entire Lambert glacial basin using speckle matching and differential interferometric SAR (InSAR) techniques, and produce a full coverage of radar coherence map over the drainage basin. With the ice velocity data, calculate the strain rate field from the initiation areas of the ice stream onto the Amery Ice Shelf; (2) Derive high-resolution digital elevation model (DEM) over the Lambert glacial drainage basin using SAR stereo, differential interferometric SAR, and GLAS laser altimetry techniques. Based on the DEM, extract ice divides and ice flow directions, delineate the snow catchment basin, and calculate the balance deformation velocity and the basal shear stress; (3) Interpolate traverse ice thickness data collected by Australian and Russian airborne radio echo sounding surveys into a regular grid, and derive a regular grid of bedrock topography in combination with the DEM; (4) Integrate newly derived ice velocity and ice thickness data as well as snow accumulation rate data compiled from previous ground-based measurements into a geographic information system (GIS), and calculate the mass flux through the ice stream at the grounding lines and net mass balance throughout the drainage basin. With these new measurements and calculations derived from advanced remote sensing techniques, we will be able to improve our understanding of dynamic behavior and current mass balance status of the Lambert glacial basin, gain an insight on the relationship between ice mass change and the variation in regional and global climate at decadal scale, and provide an evaluation on the issue of whether the Lambert glacier basin is subject to surging in the context of future climate change.