USAP-DC

{"dp_type": "Dataset", "free_text": "Crevasses"}

[{"awards": "0087144 Conway, Howard", "bounds_geometry": ["POLYGON((-150 -83.5,-148 -83.5,-146 -83.5,-144 -83.5,-142 -83.5,-140 -83.5,-138 -83.5,-136 -83.5,-134 -83.5,-132 -83.5,-130 -83.5,-130 -83.65,-130 -83.8,-130 -83.95,-130 -84.1,-130 -84.25,-130 -84.4,-130 -84.55,-130 -84.7,-130 -84.85,-130 -85,-132 -85,-134 -85,-136 -85,-138 -85,-140 -85,-142 -85,-144 -85,-146 -85,-148 -85,-150 -85,-150 -84.85,-150 -84.7,-150 -84.55,-150 -84.4,-150 -84.25,-150 -84.1,-150 -83.95,-150 -83.8,-150 -83.65,-150 -83.5))"], "date_created": "Mon, 22 Jul 2024 00:00:00 GMT", "description": "Marine ice sheets are low-pass filters of climate variability that take centuries to adjust to interior and near-terminus changes in mass balance. Constraining these century-scale changes from satellite observations that span only the last 40 years is challenging. Here, we take a different approach of carefully synthesizing different data sets to infer changes in the configurations of van der Veen and Mercer Ice Streams on the Siple Coast over the past 3000 years from englacial features encoded in ice-penetrating radar data. Englacial radar data from Conway Ridge reveal smooth, surface conformal layers overlying disrupted stratigraphy that suggest the van der Veen Ice Stream was 40 km wider over 3000 years ago. Englacial layer dating indicates that the ice stream narrowed to its present configuration between $\\sim3000$ and $\\sim1000$ years ago. Similarly disrupted stratigraphy and buried crevasses suggest that ice flowing from Mercer to Whillans Ice Stream across the northwestern tip of the ridge slowed shortly after. Using an ice-flow model capable of simulating shear margin migration, we evaluate whether small changes in ice thickness can lead to large changes in shear margin location. Our results suggest that the tip of Conway Ridge is sensitive to thinning and thickening, and that when the basal strength at the tip of the ridge increases with the height above flotation, the ice sheet shear margins can change quickly.", "east": -130.0, "geometry": ["POINT(-140 -84.25)"], "keywords": "Antarctica; Cryosphere; Siple Coast", "locations": "Siple Coast; Antarctica", "north": -83.5, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Hoffman, Andrew; Conway, Howard; Christianson, Knut", "project_titles": "Glacial History of Ridge AB, West Antarctica", "projects": [{"proj_uid": "p0010470", "repository": "USAP-DC", "title": "Glacial History of Ridge AB, West Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -85.0, "title": "Impulse HF radar data from Conway Ridge", "uid": "601810", "west": -150.0}, {"awards": "1847173 Duddu, Ravindra", "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))"], "date_created": "Tue, 04 Jul 2023 00:00:00 GMT", "description": "This dataset contains the ABAQUS input files for simulating floating ice shelves with constant density assuming linear elastic rheology or elasto-visco-plastic rheology and ABAQUS user-defined elements subroutine for water-filled cohesive zone elements.", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctica", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Gao, Yuxiang; Ghosh, Gourab; Jimenez, Stephen; Duddu, Ravindra", "project_titles": null, "projects": null, "repositories": null, "science_programs": null, "south": -90.0, "title": "Abaqus user-defined elements subroutine for cohesive zone model of hydrofracturing of surface crevasses in ice shelves", "uid": "601704", "west": -180.0}, {"awards": "0440670 Hulbe, Christina", "bounds_geometry": ["POLYGON((-180 -77,-177 -77,-174 -77,-171 -77,-168 -77,-165 -77,-162 -77,-159 -77,-156 -77,-153 -77,-150 -77,-150 -77.9,-150 -78.8,-150 -79.7,-150 -80.6,-150 -81.5,-150 -82.4,-150 -83.3,-150 -84.2,-150 -85.1,-150 -86,-153 -86,-156 -86,-159 -86,-162 -86,-165 -86,-168 -86,-171 -86,-174 -86,-177 -86,180 -86,177.5 -86,175 -86,172.5 -86,170 -86,167.5 -86,165 -86,162.5 -86,160 -86,157.5 -86,155 -86,155 -85.1,155 -84.2,155 -83.3,155 -82.4,155 -81.5,155 -80.6,155 -79.7,155 -78.8,155 -77.9,155 -77,157.5 -77,160 -77,162.5 -77,165 -77,167.5 -77,170 -77,172.5 -77,175 -77,177.5 -77,-180 -77))"], "date_created": "Fri, 19 Feb 2021 00:00:00 GMT", "description": "The surface of the Ross Ice Shelf (RIS) is textured by flow stripes, crevasses and other fea- tures related to ice flow and deformation. Here, moderate resolution optical satellite images are used to map and classify regions of the RIS characterized by different surface textures. Because the textures arise from ice deformation, the map is used to identify structural provinces with common deformation history. We classify four province types: regions associated with large outlet glaciers, shear zones, exten- sion downstream of obstacles and suture zones between provinces with different upstream sources. Adjacent provinces with contrasting histories are in some locations deforming at different rates, suggest- ing that our province map is also an ice fabric map. Structural provinces have more complicated shapes in the part of the ice shelf fed by West Antarctic ice streams than in the part fed by outlet glaciers from the Transantarctic Mountains. The map may be used to infer past variations in stress conditions and flow events that cannot be inferred from flow traces alone.", "east": 155.0, "geometry": ["POINT(-177.5 -81.5)"], "keywords": "Antarctica", "locations": "Antarctica", "north": -77.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Hulbe, Christina; Ledoux, Christine; Forbes, Martin", "project_titles": "Collaborative Research: Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams", "projects": [{"proj_uid": "p0000096", "repository": "USAP-DC", "title": "Collaborative Research: Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -86.0, "title": "MOA-derived Structural Feature Map of the Ross Ice Shelf", "uid": "601432", "west": -150.0}, {"awards": "1842021 Campbell, Seth", "bounds_geometry": ["POLYGON((-168 -82,-162.3 -82,-156.6 -82,-150.9 -82,-145.2 -82,-139.5 -82,-133.8 -82,-128.1 -82,-122.4 -82,-116.7 -82,-111 -82,-111 -82.5,-111 -83,-111 -83.5,-111 -84,-111 -84.5,-111 -85,-111 -85.5,-111 -86,-111 -86.5,-111 -87,-116.7 -87,-122.4 -87,-128.1 -87,-133.8 -87,-139.5 -87,-145.2 -87,-150.9 -87,-156.6 -87,-162.3 -87,-168 -87,-168 -86.5,-168 -86,-168 -85.5,-168 -85,-168 -84.5,-168 -84,-168 -83.5,-168 -83,-168 -82.5,-168 -82))"], "date_created": "Sat, 12 Dec 2020 00:00:00 GMT", "description": "The dataset includes GPS coordinates for crevasse/fracture locations picked from 350MHz and 400Mhz frequency GPR dataset in the Whillans/Mercer Shear Margin along the SALSA traverse route with associated kinematic outputs for each feature (shear strain rate, vorticity, dilatation). GPS coordinates are in the Antarctic Polar Stereographic projection (EPSG:3031). ", "east": -111.0, "geometry": ["POINT(-139.5 -84.5)"], "keywords": "Antarctica; Crevasses; Glaciology; GPR; GPS; Ice Sheet Flow Model; Ice Shelf Dynamics; Snow/ice; Snow/Ice; Whillans Ice Stream", "locations": "Antarctica; Whillans Ice Stream", "north": -82.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Kaluzienski, Lynn", "project_titles": "RAPID Proposal: Constraining kinematics of the Whillans/Mercer Ice Stream Confluence", "projects": [{"proj_uid": "p0010145", "repository": "USAP-DC", "title": "RAPID Proposal: Constraining kinematics of the Whillans/Mercer Ice Stream Confluence"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -87.0, "title": "2017 GPR Observations of the Whillans and Mercer Ice Streams", "uid": "601403", "west": -168.0}, {"awards": null, "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))"], "date_created": "Wed, 05 Sep 2018 00:00:00 GMT", "description": "In this data set we present observations of locations of surface crevasses in Antarctica collected from satellite images for the period between 2011 and 2015 for 46 ice shelf regions.", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctica; Crevasses; Fractures; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Sheet; Ice Shelf; Satellite Remote Sensing", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": null, "persons": "Emetc, Veronika", "project_titles": null, "projects": null, "repositories": null, "science_programs": null, "south": -90.0, "title": "Location of surface crevasses in Antarctica", "uid": "601117", "west": -180.0}, {"awards": "1043580 Reusch, David", "bounds_geometry": ["POLYGON((-180 -47,-144 -47,-108 -47,-72 -47,-36 -47,0 -47,36 -47,72 -47,108 -47,144 -47,180 -47,180 -51.3,180 -55.6,180 -59.9,180 -64.2,180 -68.5,180 -72.8,180 -77.1,180 -81.4,180 -85.7,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -85.7,-180 -81.4,-180 -77.1,-180 -72.8,-180 -68.5,-180 -64.2,-180 -59.9,-180 -55.6,-180 -51.3,-180 -47))"], "date_created": "Fri, 01 Jan 2016 00:00:00 GMT", "description": "The presence of ice ponds from surface melting of glacial ice can be a significant threshold in assessing the stability of ice sheets, and their overall response to a warming climate. Snow melt has a much reduced albedo, leading to additional seasonal melting from warming insolation. Water run-off not only contributes to the mass loss of ice sheets directly, but meltwater reaching the glacial ice bed may lubricate faster flow of ice sheets towards the ocean. Surficial meltwater may also reach the grounding lines of glacial ice through the wedging open of existing crevasses. The occurrence and amount of meltwater refreeze has even been suggested as a paleo proxy of near-surface atmospheric temperature regimes.\nUsing contemporary remote sensing (microwave) satellite assessment of surface melt occurrence and extent, the predictive skill of regional meteorological models and reanalyses (e.g. WRF, ERA-Interim) to describe the synoptic conditions favourable to surficial melt is to be investigated. Statistical approaches and pattern recognition techniques are argued to provide a context for projecting future ice sheet change.\nThe previous Intergovernmental Panel on Climate Change (IPCC AR4) commented on our lack of understanding of ice-sheet mass balance processes in polar regions and the potential for sea-level change. The IPPC suggested that the forthcoming AR5 efforts highlight regional cryosphere modeling efforts, such as is proposed here.", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctica; Atmosphere; Climate Model; Meteorology; Surface Melt", "locations": "Antarctica", "north": -47.0, "nsf_funding_programs": null, "persons": "Reusch, David", "project_titles": "Collaborative Research: Decoding \u0026 Predicting Antarctic Surface Melt Dynamics with Observations, Regional Atmospheric Modeling and GCMs", "projects": [{"proj_uid": "p0000447", "repository": "USAP-DC", "title": "Collaborative Research: Decoding \u0026 Predicting Antarctic Surface Melt Dynamics with Observations, Regional Atmospheric Modeling and GCMs"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Decoding \u0026 Predicting Antarctic Surface Melt Dynamics with Observations, Regional Atmospheric Modeling and GCMs", "uid": "600166", "west": -180.0}, {"awards": "0440670 Hulbe, Christina; 0125754 Hulbe, Christina", "bounds_geometry": ["POLYGON((-86.557 -74.355,-80.5124 -74.355,-74.4678 -74.355,-68.4232 -74.355,-62.3786 -74.355,-56.334 -74.355,-50.2894 -74.355,-44.2448 -74.355,-38.2002 -74.355,-32.1556 -74.355,-26.111 -74.355,-26.111 -75.3874,-26.111 -76.4198,-26.111 -77.4522,-26.111 -78.4846,-26.111 -79.517,-26.111 -80.5494,-26.111 -81.5818,-26.111 -82.6142,-26.111 -83.6466,-26.111 -84.679,-32.1556 -84.679,-38.2002 -84.679,-44.2448 -84.679,-50.2894 -84.679,-56.334 -84.679,-62.3786 -84.679,-68.4232 -84.679,-74.4678 -84.679,-80.5124 -84.679,-86.557 -84.679,-86.557 -83.6466,-86.557 -82.6142,-86.557 -81.5818,-86.557 -80.5494,-86.557 -79.517,-86.557 -78.4846,-86.557 -77.4522,-86.557 -76.4198,-86.557 -75.3874,-86.557 -74.355))"], "date_created": "Fri, 15 Jul 2011 00:00:00 GMT", "description": "This data set provides a structural feature map of the Ronne Ice Shelf in Antarctica (also known as the Filchner-Ronne Ice Shelf). The map was developed as part of a project to study fracture propagation in the Ronne Ice Shelf, with special focus on the Evans Ice Stream. Features were digitized from the MODIS Mosaic of Antartica (MOA), a composite of individual Moderate Resolution Imaging Spectradiometer (MODIS) images taken between 20 November 2003 and 29 February 2004, with an effective resolution of 125 m. The data set includes estimates of the shelf boundary, including ice stream grounding zones, outlets of glaciers feeding the shelf, extents of islands and ice rises, and the location of the shelf front, and features observed within the shelf, including suture zones between ice streams, streaklines, fractures (crevasses and rifts), and fold-like features. Individual features can be extracted as a group of points and grouping is used to facilitate identification and plotting. \n\nData files are available via FTP in ASCII text (.txt) format. One image file, in Portable Document Format (.pdf), shows the data included in the dataset, plotted using MATLAB. The data set also provides a MATLAB script which can be used to plot the data.", "east": -26.111, "geometry": ["POINT(-56.334 -79.517)"], "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; MOA; MODIS; Ronne Ice Shelf", "locations": "Ronne Ice Shelf; Antarctica", "north": -74.355, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Hulbe, Christina; Ledoux, Christine", "project_titles": "Collaborative Research: Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams", "projects": [{"proj_uid": "p0000096", "repository": "USAP-DC", "title": "Collaborative Research: Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -84.679, "title": "MOA-derived Structural Feature Map of the Ronne Ice Shelf", "uid": "609497", "west": -86.557}]

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