Iceberg B-15A was the largest iceberg in the world (measuring about
11,000 square kilometers) when it broke away from Western Antarctica's
Ross Ice Shelf in March 2000. It held that distinction for over three
years until splitting into two pieces in early October, 2003. The
Multi-angle Imaging SpectroRadiometer (MISR) acquired these views of the
new iceberg B-15J (resting against Ross Island) and B-15A (now free to
drift into the Southern Ocean) on October 26. Several massive icebergs
(including B-15A) had migrated during 2000 and 2001 and
ground against Ross Island,
forming a barrier that influenced wind and current patterns and altered
the regional ecology.
The two images provide information on both the spectral and angular
reflectance properties of ice types in the region. The left-hand panel
is a false-color view from MISR's vertical-viewing (nadir) camera in
which near-infrared, red and blue spectral data are displayed as red,
green and blue, respectively. Because of the tendency of water to absorb
near-infrared wavelengths, some ice types exhibit an especially bright
blue hue in this display. The right-hand panel is a multi-angular
composite from three MISR cameras, in which color acts as a proxy for
angular reflectance variations related to texture. Here, data from the
red-band of MISR's 60º forward-viewing, nadir, and 60º backward-viewing
cameras are displayed as red, green and blue, respectively. In the
southern latitudes, MISR's backward-pointing cameras receive a stronger
signal from surfaces that predominantly forward scatter sunlight (these
tend to be smooth surfaces), and MISR's forward-pointing cameras receive
a stronger signal from surfaces that predominantly backscatter sunlight
(these tend to be rougher surfaces). Thus, the colors in this
representation highlight textural properties of elements within the
scene, with blue tones indicating smoother surfaces and red/orange hues
indicating rougher surfaces.
The Multi-angle Imaging SpectroRadiometer observes the daylit Earth
continuously and every 9 days views the entire Earth between 82 degrees
north and 82 degrees south latitude. These data products were generated
from a portion of the imagery acquired during Terra orbit 20511. The
panels cover an area of 129 kilometers x 221 kilometers, and utilize
data from blocks 153 to 155 within World Reference System-2 path 56.
MISR was built and is managed by NASA's Jet Propulsion Laboratory,
Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The
Terra satellite is managed by NASA's Goddard Space Flight Center,
Greenbelt, MD. JPL is a division of the California Institute of Technology.
MISR was built and is managed by NASA's Jet Propulsion Laboratory,
Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The
Terra satellite is managed by NASA's Goddard Space Flight Center,
Greenbelt, MD. JPL is a division of the California Institute of
Technology.
Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
Text acknowledgment: Clare Averill (Raytheon / Jet Propulsion Laboratory).
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