Geology Reference
In-Depth Information
continent of Antarctica. In less than 3 weeks, the satellite
acquired a complete coverage of radar image swaths as
part of the first Antarctic Mapping Mission (AMM‐1).
Swath images have been assembled into an image mosaic
depicting the entire continent at 25 m resolution. The
mosaic provides a detailed look at ice sheet morphology,
rock outcrops, research infrastructure, the coastline, and
other features of Antarctica, as well as representing cali-
brated radar backscatter data that may provide insight
into climate processes affecting the upper few meters of
snow cover.
If one looks at the 1997 Radarsat‐1 composite map of
Antarctica, one is overwhelmed by the details of most of
its fast‐moving glaciers. Mysteries of the coastal and inte-
rior areas of this vast continent almost disappeared. No
more were the vast areas of white blanket of snow so far
seen in the air photos and satellite images produced by
using visible‐light photography. Then in 2000, Radarsat‐1
remapped Antarctic's coast. These two sets of images
were combined to produce a map that shows the
changes in the continental ice (Radarsat, 2001-2002
Annual Review, Canadian Space Agency, Government
of Canada; also
National Geographic
, February 2002).
The researchers around the world were astonished
by the detailed images of annual sea ice and changes
in the land‐fast ice shelves in the intervening 4 years.
Apart from the annual sea ice covers and ice sheets
attached to rock, floating ice shelves and associated
advancing glaciers make up nearly 60% of the coast of
Antarctica. The entire shoreline is dotted with ice shelves
with various sizes and shapes. Icebergs are calved from
these areas. Some of the tabular icebergs are massive in
their size. Due to these calving activities, changes occur
in the coastal areas on a continuous basis. Changes are
particularly noticeable in the outlines of the larger ice
shelves in the west Antarctica, such as Ross Ice Shelf,
Ronne Ice Shelf, and Larsen Ice Shelf.
Until its decommissioning in April 2013 (after nearly
18 years orbiting Earth), Radarsat‐1 used to acquire
images of Earth day or night (including long polar nights)
and in all weather-including cloud cover, rain, smoke,
Figure 5.49
Mosaic of Antarctica developed from Radarsat‐1
data © CSA 1997 received by the Canada Centre for Remote
Sensing and processed and distributed by MDA Geospatial
Services Inc (courtesy of Canadian Space Agency, government
of Canada).
(a)
(b)
10 km
Figure 5.50
Radarsat‐2 SAR image of Ward Hunt Ice Shelf with undulated surface features on 25 April 2010 in
(a) HH and (b) HV view (© MDA Geospatial Services).
