USAP-DC

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{"@context": "https://schema.org/", "@type": "Dataset", "@id": "https://www.usap-dc.org/view/dataset/600024", "additionalType": ["geolink:Dataset", "vivo:Dataset"], "name": "Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams", "description": "Flow features on the surface of the Ross Ice Shelf, West Antarctica, record two episodes of ice stream stagnation and reactivation within the last 1,000 years. We document these events using maps of streaklines emerging from individual ice streams made using visible band imagery, together with numerical models of ice shelf flow. Forward model experiments demonstrate that only a limited set of discharge scenarios could have produced the current streakline configuration. According to our analysis, Whillans Ice Stream ceased rapid flow about 850 calendar years ago and restarted about 400 years later and MacAyeal Ice Stream either stopped or slowed significantly between 800 and 700 years ago, restarting about 150 years later. Until now, ice-stream scenarios emphasized runaway retreat or stagnation on millennial time scales. Here, we identify a new scenario: century-scale stagnation and reactivation cycles, as well as lateral communication with adjacent ice streams through thickness changes on lightly grounded ice plains. This introduces uncertainty into predictions for future sea-level withdrawls by the West Antarctic Ice Sheet, which are based in part on recent slowing of Whillans Ice Stream and the stagnant condition of Kamb Ice Stream. This paper documents the evidence for delimiting the source regions (provenance) of ice now in the shelf; for bracketing the possible discharge scenarios that could have produced the patterns captured in the shelf, and shows that it is difficult to reproduce these patterns with a model without stopping and restarting individual streams. The modeling facilitated by Co-PI Hulbe\u2019s system has allowed us to cover a range of possible scenarios, and in the process to learn about other aspects of the behavior of this system. The flow variability recorded in the ice shelf provides an important reference history against which current changes can be put in context.", "citation": "Fahnestock, M. (2008) \"Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams\" U.S. Antarctic Program (USAP) Data Center. doi: https://doi.org/.", "datePublished": "2008-09-25", "keywords": [], "creator": [{"@type": "Person", "additionalType": "geolink:Person", "name": "Fahnestock, Mark", "email": "mark.fahnestock@unh.edu", "affiliation": {"@type": "Organization", "name": "University of New Hampshire, 39 College Road"}}], "distribution": [{"@type": "DataDownload", "additionalType": "http://www.w3.org/ns/dcat#DataCatalog", "encodingFormat": "text/xml", "name": "ISO Metadata Document", "url": "https://www.usap-dc.org/metadata/isoxml/600024iso.xml", "contentUrl": "/dataset/filename"}, {"@type": "DataDownload", "@id": "https://www.usap-dc.org/view/dataset/600024", "additionalType": "dcat:distribution", "url": "https://www.usap-dc.org/view/dataset/600024", "contentUrl": "/dataset/filename", "encodingFormat": "text/html"}, {"@type": "DataDownload", "@id": "https://www.usap-dc.org/view/dataset/600024", "additionalType": "dcat:distribution", "url": "https://www.usap-dc.org/view/dataset/600024", "contentUrl": "/dataset/filename", "encodingFormat": "text/html"}], "identifier": {"@type": "PropertyValue", "url": "https://www.usap-dc.org/view/dataset/600024", "value": "https://www.usap-dc.org/view/dataset/600024"}, "contributor": [{"@type": "Role", "roleName": "credit", "description": "funderName:NSF:GEO:PLR:Antarctic Glaciology awardNumber:0440636 awardTitle: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"}], "license": [{"@type": "CreativeWork", "URL": "https://creativecommons.org/licenses/by-nc/4.0/", "name": "MD_Constraints", "description": "useLimitation: Creative Commons Attribution-NonCommercial v4.0 Generic [CC BY-NC 4.0]."}, {"@type": "CreativeWork", "name": "MD_LegalConstraints", "description": "accessConstraints: license. otherConstraints: Creative Commons Attribution-NonCommercial v4.0 Generic [CC BY-NC 4.0]."}, {"@type": "CreativeWork", "name": "MD_SecurityConstraints", "description": "classification: "}], "publisher": {"@type": "Organization", "name": "U.S. Antarctic Program (USAP) Data Center"}, "spatialCoverage": []}

Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams Cite as Fahnestock, M. (2008) "Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams" U.S. Antarctic Program (USAP) Data Center. doi: https://doi.org/. AMD - DIF Record(s) fahnestock_0440636_1 Abstract Flow features on the surface of the Ross Ice Shelf, West Antarctica, record two episodes of ice stream stagnation and reactivation within the last 1,000 years. We document these events using maps of streaklines emerging from individual ice streams made using visible band imagery, together with numerical models of ice shelf flow. Forward model experiments demonstrate that only a limited set of discharge scenarios could have produced the current streakline configuration. According to our analysis, Whillans Ice Stream ceased rapid flow about 850 calendar years ago and restarted about 400 years later and MacAyeal Ice Stream either stopped or slowed significantly between 800 and 700 years ago, restarting about 150 years later. Until now, ice-stream scenarios emphasized runaway retreat or stagnation on millennial time scales. Here, we identify a new scenario: century-scale stagnation and reactivation cycles, as well as lateral communication with adjacent ice streams through thickness changes on lightly grounded ice plains. This introduces uncertainty into predictions for future sea-level withdrawls by the West Antarctic Ice Sheet, which are based in part on recent slowing of Whillans Ice Stream and the stagnant condition of Kamb Ice Stream. This paper documents the evidence for delimiting the source regions (provenance) of ice now in the shelf; for bracketing the possible discharge scenarios that could have produced the patterns captured in the shelf, and shows that it is difficult to reproduce these patterns with a model without stopping and restarting individual streams. The modeling facilitated by Co-PI Hulbe’s system has allowed us to cover a range of possible scenarios, and in the process to learn about other aspects of the behavior of this system. The flow variability recorded in the ice shelf provides an important reference history against which current changes can be put in context. Creator(s): Fahnestock, Mark Date Created: 2008-09-25 Repository: USAP-DC (current) - AMD-RESCUE (original) License: Creative Commons Attribution-NonCommercial v4.0 Generic [CC BY-NC 4.0] Award(s) NSF 0440636 Version: 1 Related Project(s) 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