This colorful image of the Arctic National Wildlife Refuge and the
Beaufort Sea was acquired by the Multi-angle Imaging SpectroRadiometer's
nadir (vertical-viewing) camera on August 16, 2000, during Terra orbit
3532. The swirling patterns apparent on the Beaufort Sea are small
ice floes driven by turbulent water patterns, or eddies, caused by
the interactions of water masses of differing salinity and
temperature. By this time of year, all of the seasonal ice which
surrounds the north coast of Alaska in winter has broken up, although
the perennial pack ice remains further north. The morphology of the
perennial ice pack's edge varies in response to the prevailing
wind. If the wind is blowing strongly toward the perennial pack
(that is, to the north), the ice edge will be more compact. In this
image the ice edge is diffuse, and the patterns reflected by the ice
floes indicate fairly calm weather.
The Arctic National Wildlife Refuge (often abbreviated to ANWR) was
established by President Eisenhower in 1960, and is the largest
wildlife refuge in the United States. Animals of the Refuge include the
130,000-member Porcupine caribou herd, 180 species of birds from four
continents, wolves, wolverine, polar and grizzly bears, muskoxen,
foxes, and over 40 species of coastal and freshwater fish. Although
most of ANWR was designated as wilderness in 1980, the area along
the coastal plain was set aside so that the oil and gas reserves
beneath the tundra could be studied. Drilling remains a topic of
contention, and an energy bill allowing North Slope oil development
to extend onto the coastal plain of the Refuge was approved by the
US House of Representatives on August 2, 2001.
The Refuge encompasses an impressive variety of arctic and subarctic
ecosystems, including coastal lagoons, barrier islands, arctic tundra,
and mountainous terrain. Of all these, the arctic tundra is the
landscape judged most important for wildlife. From the coast inland to
an average of 30-60 kilometers, arctic tundra dominates the coastal
plain, until reaching the foothills of the Brooks Mountain Range.
Beneath the tundra, a layer of permafrost reaches an average depth of
600 meters, restricting water drainage through the soil, and
increasing the sensitivity of tundra vegetation to disturbance.
Precipitation is scarce (less than 16 centimeters per year) and the
small amount of melt water or rain that soaks into the tundra remains
near the surface. This is why the coastal plain can be classified as
a wetland.
The western boundary of the Refuge is marked by the Canning River,
about halfway between the center and left-hand side of the image, and
the eastern boundary is near the right-hand edge at the US/Canadian
border. The two permanent human settlements within the image area are
Kaktovic near the tip of the large rounded peninsula, and Arctic
Village south of the Brooks Range near the southern Refuge boundary.
The area represented by the image is approximately 380 kilometers x
540 kilometers.
Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
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