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Pine Island Glacier, Antarctica
This page contains archived content and is no longer being updated.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.
This pair of Multi-angle Imaging Spectroradiometer (MISR) images of the Pine Island Glacier in western
Antarctica was acquired on December 12, 2000 during Terra orbit 5246. At
left is a conventional, true-color image from the downward-looking
(nadir) camera. The false-color image at right is a composite of red
band data taken by the MISR forward 60-degree, nadir, and aftward
60-degree cameras, displayed in red, green, and blue colors,
respectively. Color variations in the left (true-color) image highlight
spectral differences. In the multi-angle composite, on the other hand,
color variations act as a proxy for differences in the angular
reflectance properties of the scene. In this representation, clouds show
up as light purple. Blue to orange gradations on the surface indicate a
transition in ice texture from smooth to rough. For example, the bright
orange 'carrot-like' features are rough crevasses on the glacier's
tongue. In the conventional nadir view, the blue ice labeled 'rough
crevasses' and 'smooth blue ice' exhibit similar coloration, but the
multi-angle composite reveals their different textures, with the
smoother ice appearing dark purple instead of orange. This could be an
indicator of different mechanisms by which this ice is exposed. The
multi-angle view also reveals subtle roughness variations on the frozen
sea ice between the glacier and the open water in Pine Island Bay.
To the left of the 'icebergs' label are chunks of floating ice.
Additionally, smaller icebergs embedded in the frozen sea ice are
visible below and to the right of the label. These small icebergs are
associated with dark streaks. Analysis of the illumination geometry
suggests that these streaks are surface features, not shadows. Wind-
driven motion and thinning of the sea ice in the vicinity of the
icebergs is one possible explanation.
Recently, Robert Bindschadler, a glaciologist at the NASA Goddard Space
Flight Center discovered in Landsat 7 imagery a newly-formed crack
traversing the Pine Island Glacier. This crack is visible as an
off-vertical dark line in the MISR nadir view. In the multi-angle
composite, the crack and other stress fractures show up very clearly in
bright orange. Radar observations of Pine Island Glacier in the 1990's
showed the glacier to be shrinking, and the newly discovered crack is
expected to eventually lead to the calving of a major iceberg.