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Coastal-Change and Glaciological Maps of Antarctica

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Coastal-Change and Glaciological Maps of Antarctica Coastal-Change and Glaciological Maps of Antarctica Changes in the area and volume of the 1992 and 1995 European Space Agency two polar ice sheets in Antarctica (fig. 1) and (ESA) Remote Sensing Satellite (ERS) location of floating ice fronts during the Greenland are intricately linked to changes in radar images, 9 September–2 October 1997 time periods represented by the imagery. global climate, and could result in sea-level RADARSAT images, Landsat 7 Enhanced • Determine glacier-ice velocities of changes that could severely affect the densely Thematic Mapper (ETM+) images (April selective outlet glaciers, ice streams, populated coastal regions on Earth. Melting 1999–May 2003), and Moderate Resolution and ice shelves in some coastal regions. of the West Antarctica part of the Antarctic Imaging Spectroradiometer (MODIS) images ice sheet alone could cause a sea-level rise (post-mid-December 1999). The different data • Compile an inventory of named (from of approximately 6 meters (m). The poten- sets allow determination of coastal change published maps and gazetteers) and tial sea-level rise after melting of the entire in Antarctica for >30 years where suitable unnamed (from analysis of Landsat and Antarctic ice sheet is estimated to be about images exist. Coastal change has been most other images) outlet glaciers and ice 73 m. In spite of its importance, the mass pronounced on the Antarctic Peninsula in the streams in Antarctica. balance (the net volumetric gain or loss) of last few decades, where the Wordie Ice Shelf the Antarctic ice sheet is poorly known; it is has practically disappeared, the northern part • Publish the results of the analyses as not known whether the ice sheet is growing of the Larsen Ice Shelf has disintegrated, and Coastal-Change and Glaciological Maps or shrinking. As a result, measurement of other ice shelves are also changing. Coopera- of Antarctica (I–2600), of the USGS changes in the Antarctic ice sheet has been tion with other Antarctic mapping groups now Geologic Investigations Series (I–Maps) given a very high priority in recommendations includes scientists from Italy, Russia, Norway, (fig. 2). Most 1:1,000,000-scale maps by the Polar Research Board of the National Canada. Australia, Argentina, and Germany. extend to the southernmost nunatak Research Council, by the Scientific Commit- The coastal-change and glaciological map- within each map area or to the southern- tee on Antarctic Research (SCAR), and by the ping task, an element of the Glacier Studies most extent of Landsat images (about National Science Foundation’s Office of Polar Project, has several objectives: 81.5°S. lat.), although for some ice Programs. • Determine coastline changes in Antarc- shelves, RADARSAT or MODIS images An extensive archive of early 1970s tica that have occurred at three or more were used to extend maps further south. Landsat 1, 2, and 3 Multispectral Scanner time intervals between the mid-1970s The 1:1,000,000-scale maps will be (MSS) images of Antarctica was the impe- and the latest available images. combined to produce a 1:5,000,000- tus for the U.S. Geological Survey (USGS), scale map of Antarctica (in both printed in cooperation with Scott Polar Research • Establish an accurate base-line series and digital formats). Institute (Cambridge, U.K.), to carry out a of 1:1,000,000-scale maps (in printed Ice fronts, iceberg tongues, and glacier comprehensive analysis of the glaciological and/or digital format) (fig. 2) that tongues are the most dynamic and changeable features of the coastal regions of Antarctica. defines, from the analysis of remotely features in the coastal regions of Antarctica. The project was later modified to include sensed data, the glaciological charac- Floating ice margins are subject to frequent analysis of coastal change using Landsat 4 and teristics of the coastline of Antarctica, and large calving events or rapid flow. These 5 MSS and Thematic Mapper (TM) images for example, floating ice (ice fronts) situations lead to annual and decadal changes from the late 1980s/early 1990s, declassi- and grounded ice (ice walls), and the in the position of ice fronts on the order of fied 1963 Argon (Corona Program) images, W0E 0 E W 0 E 60S 0E 60S Published (Date of Publication) and Planned Fimbul Ice Rilser-Larsen USGS I–2600 Maps: Ice Shelf Shelf Lazarev Ice Shelf Brunt Ice Shelf A-Trinity Peninsula (2006) P-West Ice Shelf* V U T Weddell B-Larsen Ice Shelf (2008) Q-Amery Ice Shelf* Larsen A S Ice Shelf Sea R C-Palmer Land (2009) R-Mawson Coast* Amery W 80S Ice Shelf 80S D-Ronne Ice Shelf (2005) S-Prince Olav Coast* Ronne C Ice West B Q E-Eights Coast (2004) T-Princess Ragnhild Coast* Shelf EAST Ice Shelf George VI Filchner F-Bakutis Coast (2005) U-Fimbul Ice Shelf* Ice Shelf Ice Shelf D P 90W 90E 90W 90E G-Saunders Coast (2003) V-Cape Norvegia* WEST E H-Ross Ice Shelf (2008) W-Filchner Ice Shelf-Coats ANTARCTICA ANTARCTICA O Abbot I-Ross Island (2010) Land* Ice Shelf Ross Shackleton F Ice Shelf N Ice Shelf G I Getz H J-Drygalski Ice Tongue* X-Antarctica Ice Shelf Sulzberger Voyeykov J M Ice Shelf K-Oates Coast* IceIce ShelfShelf L L-George V Coast* Cook Ice Shelf 0 1000 KILOMETERS K M-Banzare Coast* 0 1000 KILOMETERS N-Budd Coast* O-Queen Mary Coast* W180W 180 E W180W 180 E Figure 1. Index map to the principal geo- Figure 2. Index map showing the locations and names of the published and planned 1:1,000,000- graphic features of Antarctica, including scale coastal-change and glaciological maps of Antarctica. The dates (2004) of published maps the ice shelves where large coastal-change are shown that are available in print and digital formats [http://pubs.usgs.gov/imap/2600/]. events commonly occur. U.S. Department of the Interior Fact Sheet FS 2005–3055 U.S. Geological Survey (Supersedes FS–50–98) Revised September 2011 several kilometers, even tens of kilometers in available maps are used in the compilation The Coastal-Change and Glaciological extreme cases of major calving events (fig. 3). of the coastal-change and glaciological maps Maps of Antarctica are being produced as On the coastal-change and glaciologi- to produce a reasonably complete prelimi- Task 2 of the Glacier Studies Project [http:// cal maps, the positions of the dynamic ice nary inventory of named and unnamed outlet www.glaciers.er.usgs.gov] of the U.S. Geo- fronts as observed on remotely sensed data glaciers and ice streams and also to define, logical Survey Geology Disciplines’ Earth have been mapped and annotated with the more accurately, related glaciological features Surface Dynamics Program, a component of exact date of each position. This record such as ice domes, ice piedmonts, ice shelves, 13 interagency Federal U.S. Climate Change makes it possible to analyze changes that ice rises, ice rumples, glacier tongues, iceberg Science Program, of which the U.S. Depart- have occurred. Although calving does occur tongues, etc. ment of the Interior is a member. along ice walls, the magnitude of the change on an annual to decadal basis is generally not discernible on the images; therefore, ice walls can be used as relatively stable reference fea- tures against which to measure other changes For more information, please contact: along the coast. Only a single observation date Dr. Richard S. Williams, Jr. is given for the position of ice walls. U.S. Geological Survey Velocities of floating glaciers (such as Woods Hole Coastal and Marine glacier tongues, ice streams, ice shelves) are Science Center determined by three methods. (1) An interac- 384 Woods Hole Road tive one in which crevasse patterns are traced Woods Hole, MA 02543-1598 visually on images. (2) An auto-correlation Tel: 508-540-6405 program developed by the U.S. National e-mail: [email protected] Aeronautics and Space Administration (NASA). The larger glacier tongues and ice Jane G. Ferrigno shelves have well-developed rift patterns that U.S. Geological Survey can be used for velocity measurements. Under 926A National Center optimum conditions, errors can be as small as 12201 Sunrise Valley Drive ±0.02 km per year (a–1), but for most Landsat Reston, VA 20192-0002 image pairs, where registration of features is Tel: 703-648-6360 not as accurate, the accuracy of velocity vec- e-mail: [email protected] tors is ±0.1 km a–1. (3) Ice-surface velocities can be determined from satellite radar inter- Kevin M. Foley ferometry, a technique developed by scientists U.S. Geological Survey at the California Institute of Technology (Jet 926A National Center Propulsion Laboratory) and NASA. 12201 Sunrise Valley Drive Producing a sophisticated glacier inventory Reston, VA 20192-0002 of Antarctica according to the requirements Tel: 703-648-5285 of the World Glacier Monitoring Service, as e-mail: [email protected] part of its ongoing “World Glacier Inventory” program, is difficult to accomplish with the present state of glaciological knowledge about Antarctica. Landsat and other images and Figure 3. Left, Landsat MSS image of margin of the Filchner Ice Shelf, Weddell Sea, West Antarctica, on 11 November 1973. Right, Landsat image of the same area on 18 October 1986 after a major calving event..
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