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Icebergs Adrift in the Amundsen Sea
This page contains archived content and is no longer being updated. At the time of publication, it represented the best available science. However, more recent observations and studies may have rendered some content obsolete.
The Thwaites Ice Tongue is a large sheet of glacial ice extending from the West
Antarctic mainland into the southern Amundsen Sea. A large crack in the Thwaites
Tongue was discovered in imagery from Terras Moderate Resolution Imaging
Spectroradiometer (MODIS). Subsequent widening of the crack led to the calving
of a large iceberg. The development of this berg, designated B-22 by the
National Ice Center, can be observed in these images from the Multi-angle
Imaging SpectroRadiometer, also aboard Terra. The two views were acquired by
MISRs nadir (vertical-viewing) camera on March 10 and 24, 2002.
The B-22 iceberg, located below and to the left of image center, measures
approximately 82 kilometers long x 62 kilometers wide. Comparison of the two
images shows the berg to have drifted away from the ice shelf edge. The breakup
of ice near the shelf edge, in the area surrounding B-22, is also visible in the
These natural-color images were acquired during Terra orbits 11843 and 12047,
respectively. At the right-hand edge is Pine Island Bay, where the calving of
another large iceberg (B-21) occurred in November 2001. B-21 subsequently split
into two smaller bergs, both of which are visible to the right of B-22.
Antarctic researchers have reported an increase in the frequency of iceberg
calvings in recent years. Whether this is the result of a regional climate
variation, or connected to the global warming trend, has not yet been