As a consequence of its capability to retrieve cloud-top elevations,
stereoscopic observations from the Multi-angle Imaging
SpectroRadiometer (MISR) can discriminate clouds from snow and ice.
The central portion of Russia's East Siberian Sea, including one of
the New Siberian Islands, Novaya Sibir, are portrayed in these views
from data acquired on May 28, 2002.
The left-hand image is a natural color view from MISR's nadir camera.
On the right is a height field retrieved using automated computer
processing of data from multiple MISR cameras. Although both clouds
and ice appear white in the natural color view, the stereoscopic
retrievals are able to identify elevated clouds based on the
geometric parallax which results when they are observed from
different angles. Owing to their elevation above sea level, clouds
are mapped as green and yellow areas, whereas land, sea ice, and very
low clouds appear blue and purple. Purple, in particular, denotes
elevations very close to sea level. The island of Novaya Sibir is
located in the lower left of the images. It can be identified in
the natural color view as the dark area surrounded by an expanse of
fast ice. In the stereo map the island appears as a blue region
indicating its elevation of less than 100 meters above sea level.
Areas where the automated stereo processing failed due to lack of
sufficient spatial contrast are shown in dark gray. The northern edge
of the Siberian mainland can be found at the very bottom of the panels,
and is located a little over 250 kilometers south of Novaya Sibir.
Pack ice containing numerous fragmented ice floes surrounds the
fast ice, and narrow areas of open ocean are visible.
The East Siberian Sea is part of the Arctic Ocean and is ice-covered
most of the year. The New Siberian Islands are almost always covered
by snow and ice, and tundra vegetation is very scant. Despite continuous
sunlight from the end of April until the middle of August, the ice
between the island and the mainland typically remains until August or
September.
The Multi-angle Imaging SpectroRadiometer views almost the entire Earth
every 9 days. These images were acquired during Terra orbit 12986 and
cover an area of about 380 kilometers x 1117 kilometers. They utilize
data from blocks 24 to 32 within World Reference System-2 path 117.
Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
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