NASA instruments flying on the Terra satellite have
observed the calving of an iceberg and the breakup of an ice
shelf in Antarctica, roughly 2,100 kilometers (1,300 miles)
from one another.

Last month, a large crack developed in the Thwaites
Tongue, a large sheet of glacial ice that extends from the
West Antarctica mainland into the southern Amundsen Sea. A
piece broke away, or calved, forming an iceberg designated B-
22 by the National Ice Center. In February, a section of the
Larsen B ice shelf, located on the familiar finger-like
Antarctic Peninsula, collapsed and broke away from the

The progression of both breakups were initially observed
by NASA’s Moderate Resolution Imaging Spectroradiometer.
Images of the subsequent calving and ice shelf breakup were
captured by NASA’s Multi-angle Imaging SpectroRadiometer.

The B-22 iceberg images are available at:

The B-22 iceberg measures approximately 82 kilometers
(about 32 miles) long by 62 kilometers (about 24 miles) wide.
Comparison of the images shows the iceberg, located below and
to the left of center, has drifted away from the ice shelf.
The breakup of ice near the shelf edge, in the area
surrounding B-22, is also visible in the later image.

These natural-color images were acquired on March 10 and
24, 2002, respectively. Antarctic researchers have reported
an increase in the frequency of iceberg calving in recent
years. It has not yet been established if this is a result of
regional climate variation or the global warming trend.

The two views of the ice shelf breakup, acquired on March
7, 2002, provide helpful chemical and topographical
perspectives. In the left-hand image, near-infrared, red and
blue data from the Multi-angle Imaging SpectroRadiometer’s
nadir (vertical-viewing) camera causes water ice within the
ice shelf to appear vibrant blue. Water has an intrinsic blue
color due to the selective absorption of longer wavelengths
such as red and infrared, and the translucent properties of
ice within the collapsing shelf enables this absorption to be

The ice shelf images are available at:

Data from three different cameras on the instrument and
one color channel were combined to create the multi-angle
composite on the right. Because vertical protrusions or
depressions within textured surfaces appear brighter on their
illuminated faces, the orange color in the multi-angle
composite suggests a rough ice surface.

The Multi-angle Imaging SpectroRadiometer, built and
managed by NASA’s Jet Propulsion Laboratory, Pasadena, Calif.,
is one of several Earth-observing experiments aboard Terra,
launched in December 1999. The instrument acquires images of
Earth at nine angles simultaneously, using nine separate
cameras pointed forward, downward, and backward along its
flight path. The Terra mission supports NASA’s Earth Science
Enterprise, a long-term research effort designed to help
better understand and protect our home planet. More
information about the radiometer is available at .

JPL is a division of the California Institute of
Technology in Pasadena.