2/9/23, 9:41 AM Coastal-Change and Glaciological Maps of Antarctica

web.archive.org/web/20050206133021/http://pubs.usgs.gov/fs/fs50-98/ 1/4

The Wayback Machine - http://web.archive.org/web/20050206133021/http://pubs.usgs.gov:80/fs/fs50-98/

Coastal-Change and Glaciological Maps of Antarctica

Changes in the area and volume of the two polar ice sheets in Antarctica (fig. 1) and Greenland are intricately

linked to changes in global climate and could result in sea-level changes that would severely affect the densely

populated coastal regions on Earth. Melting of the West Antarctica part of the Antarctic ice sheet alone could

cause a worldwide sea-level rise of approximately 8 m. The potential sea-level rise after melting of the entire

Antarctic ice sheet is estimated to be 73 m. In spite of its importance, the mass balance (the net volumetric gain

or loss) of the Antarctic ice sheet is poorly known; it is not known whether the ice sheet is growing or shrinking.

As a result, measurement of changes in the Antarctic ice sheet has been given a very high priority in

recommendations by the Polar Research Board of the National Research Council, by the Scientific Committee

on Antarctic Research (SCAR), and by the National Science Foundation's Office of Polar Programs.

Figure 1. Index map to the principal geographic features of

Antarctica, including the ice shelves where large coastalchange events commonly occur.

An extensive archive of early 1970's Landsat 1, 2, and 3 Multispectral Scanner (MSS) images of Antarctica was

the impetus for the U.S. Geological Survey (USGS), in cooperation with Scott Polar Research Institute

(Cambridge, U.K.), to carry out a comprehensive analysis of the glaciological features of the coastal regions of

Antarctica. The project was later modified to include analysis of coastal change using Landsat 4 and 5 MSS and

Thematic Mapper (TM) images from the late 1980's/early 1990's, declassified 1963 Argon (Corona Program)

images, and 1992 and 1995 European Space Agency (ESA) Remote-Sensing Satellite (ERS) radar images. The

different data sets allow determination of coastal change in Antarctica over 15-20 years for the MSS and TM

images and over as much as 32 years where Argon and ERS images exist, such as the Antarctic Peninsula.

Coastal change has been most pronounced in the Antarctic Peninsula in the last few decades, where the Wordie
2/9/23, 9:41 AM Coastal-Change and Glaciological Maps of Antarctica

web.archive.org/web/20050206133021/http://pubs.usgs.gov/fs/fs50-98/ 2/4

Ice Shelf has practically disappeared, the northern part of the Larsen Ice Shelf has disintegrated, and other ice

shelves are also changing. Cooperation with other Antarctic mapping groups now includes scientists from Italy,

Russia, Norway, Canada, Australia, Argentina, and Germany.

The coastal-change and glaciological mapping task, an element of the Glacier Studies Project, has five

objectives:

To determine coastline changes in Antarctica that have occurred between the mid-1970's and the late

1980's/early 1990's (Landsat 1-5 MSS and Landsat 4 and 5 TM) and between 1963 and 1995 where the

data are available.

To establish an accurate baseline series of 1:1,000,000-scale maps (fig. 2) that defines, from the analysis

of remotely sensed data, the glaciological characteristics (for example, floating ice, grounded ice) of the

coastline of Antarctica and the location of floating ice fronts during the time periods represented by the

imagery.

To determine velocities of outlet glaciers, ice streams, and ice shelves from comparison of Landsat images

of the same areas taken over time.

To compile a comprehensive inventory of named (from published maps, gazetteers, and compact discs)

and unnamed (from analysis of Landsat images) outlet glaciers and ice streams in Antarctica that are

mappable from Landsat and other satellite images.

To publish the results of the analyses in 24 maps as I-2600-A-X of the USGS Geologic Investigations

Series (I-Maps) (fig. 2). Each 1:1,000,000-scale map extends to the southernmost nunatak within each

map area or to the southernmost extent of Landsat images (about 81.5°S. lat.). The 1:1,000,000-scale maps

will be combined to produce a 1:5,000,000-scale map of Antarctica.

Planned USGS I-2600 Maps

A-Trinity Peninsula

B-Larsen Ice Shelf

C-Palmer Land

D-Ronne Ice Shelf

E-Eights Coast

F-Bakutis Coast (1997)

G-Saunders Coast

H-Ross Ice Shelf

I-Ross Island

J-Drygalski Ice Tongue

K-Oates Coast

L-George V Coast

M-Banzare Coast

N-Knox Coast

O-Queen Mary Coast

P-Amery Ice Shelf

Q-Lambert Glacier

R-Mawson Coast

S-Prince Olav Coast

T-Princess Ragnhild Coast

U-Fimbul Ice Shelf

V-Cape Norvegia

W-Caird Coast

X-Berkner Island

Figure 2. Index map showing the locations and names of the 24 planned 1:1,000,000-scale coastal-change and

glaciological maps of Antarctica. The first (prototype) map, I-2600-F, "Coastal-Change and Glaciological
2/9/23, 9:41 AM Coastal-Change and Glaciological Maps of Antarctica

web.archive.org/web/20050206133021/http://pubs.usgs.gov/fs/fs50-98/ 3/4

Map of the Bakutis Coast, Antarctica: 1972-1990," was published by the U.S. Geological Survey in 1997.

Ice fronts, iceberg tongues, and glacier tongues are the most dynamic and changeable features in the coastal

regions of Antarctica. Seaward of the grounding line, the floating ice margin is subject to frequent and large

calving events or rapid flow. Both of these situations lead to annual and decadal changes in the position of ice

fronts on the order of several kilometers, even tens of kilometers in extreme cases of major calving events (fig.

3).

Figure 3. Left, Landsat MSS image of margin of the Filchner Ice Shelf,

Weddell Sea, West Antarctica, on 11 November 1973. Right, Landsat MSS

image of the same area on 18 October 1986 after a major calving event.

On the coastal-change and glaciological maps, the positions of the dynamic ice fronts as observed on remotely

sensed data have been mapped and annotated with the date of each position. This record makes it possible to

analyze changes that have occurred. Although calving does occur 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 features against which to measure other changes along the coast. Only a single

observation date is given for the position of ice walls. Velocities of floating glaciers (such as glacier tongues, ice

streams, ice shelves) are determined by two methods: (1) an interactive one in which crevasse patterns are traced

visually on images and (2) an auto-correlation program developed by the U.S. National Aeronautics and Space

Administration (NASA). The larger glacier tongues and ice shelves have well-developed rift patterns that can be

used for velocity measurements. Under optimum conditions, errors can be as small as ±0.02 km per year, but for

most Landsat image pairs, where registration of features is not as accurate, the accuracy of velocity vectors is

±0.1 km per year. A third method for calculating ice surface velocity using satellite radar interferometry has

been developed by scientists at the California Institute of Technology (Jet Propulsion Laboratory) and NASA

and offers promise in some areas.

Producing a sophisticated glacier inventory of Antarctica according to the requirements of the World Glacier

Monitoring Service, as part of its ongoing "World Glacier Inventory" program, is impossible with the present

state of glaciological knowledge about Antarctica. Landsat and other images and available maps are used in the

compilation of the coastal-change and glaciological maps to produce a reasonably complete preliminary

inventory of named and unnamed outlet glaciers and ice streams and also to define, more accurately, related

glaciological features such as ice domes, ice piedmonts, ice shelves, ice rises, ice rumples, glacier tongues, and

iceberg tongues.

For more information, please contact:

Richard S. Williams, Jr.

U.S. Geological Survey

Woods Hole Field Center

Jane G. Ferrigno

U.S. Geological Survey

955 National Center
2/9/23, 9:41 AM Coastal-Change and Glaciological Maps of Antarctica

web.archive.org/web/20050206133021/http://pubs.usgs.gov/fs/fs50-98/ 4/4

384 Woods Hole Road

Woods Hole, MA 02543-1598

Telephone: 508-457-2347

Fax: 508-457-2310

E-mail: rswilliams@usgs.gov

12201 Sunrise Valley Drive

Reston, VA 20192

Telephone: 703-648-6360

Fax: 703-648-6524

E-mail: jferrign@usgs.gov

The Coastal-Change and Glaciological Maps of Antarctica effort is being done under the Glacier Studies Project

of the Earth Surface Dynamics component of the USGS Global Change Research Program. For more

information, visit the World Wide Web site at http://www.glaciers.er.usgs.gov/

U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 050-98

May 1998

This page is http://pubs.usgs.gov/factsheet/fs50-98/

Maintained by Eastern Publications Group Web Team

Last revised 02-08-99