Map: Coastal-Change and Glaciological Map of the Larsen Ice Shelf Area, Antarctica: 1940–2005

by
United States Geological Survey

Map I-2600-B is one of a series of maps produced by the United States Geological Survey in cooperation with the British Antarctic Survey, the Scott Polar Research Institute, and the Bundesamt für Kartographie und Geodäsie.

    According to the USGS "Coastal-Change and Glaciological Maps of Antarctica" program:

    • Changes in the area and volume of polar ice sheets are intricately linked to changes in global climate
    • Measurement of changes in area and mass balance of the Antarctic ice sheet was given a very high priority in recommendations by the Polar Research Board of the National Research Council (1986), in subsequent recommendations by the Scientific Committee on Antarctic Research (SCAR) (1989, 1993), and by the National Science Foundation’s (1990) Division of Polar Programs
    • On the basis of the above recommendations, the archive of early 1970s Landsat 1, 2, and 3 Multispectral Scanner (MSS) images of Antarctica and the subsequent repeat coverage made possible with Landsat and other satellite images provided an excellent means of documenting changes in the cryospheric coastline of Antarctica
    • The availability of this information provided the impetus for carrying out a comprehensive analysis of the glaciological features of the coastal regions and changes in ice fronts of Antarctica
    • The project was later modified to include Landsat 4 and 5 MSS and Thematic Mapper (TM) images [and in some areas Landsat 7 Enhanced Thematic Mapper Plus (ETM+) images], RADARSAT images, aerial photography, and other data where available, to compare changes that occurred during a 20- to 25- or 30-year time interval (or longer where data were available, as in the Antarctic Peninsula)
    • The results of the analysis are being used to produce a digital database and a series of USGS Geologic Investigations Series Maps (I–2600)

    Objectives

    The coastal-change and glaciological mapping project has five primary objectives, listed as follows:

    1. to determine coastline changes that have occurred during the past three decades, or longer where additional information exists;
    2. to establish an accurate baseline series of1:1,000,000- scale maps (fig. 1) that defines, from the analysis of Landsat and other satellite images, the glaciological characteristics (for example, floating ice, grounded ice, and so forth) of the coastline of Antarctica during three main time intervals: (1) early 1970s (Landsat 1, 2, or 3), (2) middle 1980s to early 1990s (Landsat 4 or 5), and (3) late 1990s to early 2000s (RADARSAT or Landsat 7 ETM+);
    3. to determine velocities of outlet glaciers, ice streams, and ice shelves, and the position of the grounding line, from analysis of Landsat images and other sources;
    4. to compile a comprehensive inventory of named (from published maps) and unnamed (from analysis of Landsat images) outlet glaciers and ice streams in Antarctica that are mappable from Landsat and other satellite images or from ancillary sources (for example, maps, gazetteers, digital databases, and so forth) (Swithinbank, 1980, 1985; Alberts, 1981, 1995; National Science Foundation, 1989; British Antarctic Survey and others, 1993);
    5. to compile a 1:5,000,000-scale map of Antarctica derived from the 1:1,000,000-scale maps. Each 1:1,000,000-scale map, apart from the three sheets covering the Antarctic Peninsula, extends to the southernmost nunatak within each map area or to the southernmost extent of Landsat images (about lat 81.5º S.). The coverage area of some maps (for example, those covering the Ronne and Filchner Ice Shelves) was extended farther south to encompass the entire ice shelf.