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 cover an area of about 380 kilometers x 1117 kilometers.