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Images from space, via Alaska, for 15 years
By Ned Rozell

 

August 07, 2006
Monday


On an August day 15 years ago, a dozen people crowded around a computer in Fairbanks and saw what they hoped to see-islands and ice rafts north of Hudson Bay, Canada, transmitted to them from a satellite 500 miles overhead. After letting out a collective whoop, they compared the snapshot from above to maps of northern Canada, marveling at the view Alaska's newest scientific tool provided them.


jpg Alaska Satellite Facility

The Alaska Satellite Facility uses the 10-meter receiving antenna on top of UAF's Elvey Building, at right, on the west ridge of the UAF campus. The building at left is the International Arctic Research Center.
Photo by Ned Rozell.

From that beginning in 1991, the Alaska Satellite Facility at the University of Alaska Fairbanks has received millions of data bits from orbiting satellites, and scientists have used the view from space to study things that are hard to view any other way. Those things include the amount of sea ice that forms on the northern oceans, or the slight inflation of an Aleutian volcano that may hint of an eruption.

All of this action takes place through one of the most noticeable features of the Fairbanks landscape: a 10-meter dish that looks like a birdbath sitting on top of the Elvey Building on the UAF campus. The facility also uses a similar antenna in the woods a bit west of the Elvey Building.

About 9,000 manmade satellites are zipping around Earth right now, though only a few of them are sending back useful material. The Alaska Satellite Facility now receives data from two NASA satellites, two satellites owned by Canada, a satellite owned by 13 European countries, and a recently launched satellite owned by Japan. At the time of the Alaska Satellite Facility's birth, officials at NASA were contemplating sending a new satellite into orbit but decided a station that could retrieve data from Earth-observing satellites was a better use of their money. They installed the antenna on the top of the structure that stands highest in the sky on the UAF campus, the eight-story Elvey Building.

Some orbiting satellites retrieve images of Earth even through cloud cover or darkness. Riding aboard the Canada satellite known as RADARSAT-1 is a synthetic aperture radar instrument that sends down microwave pulses that hit glacier, sidewalk, ocean and other surface features. Those features can either scatter microwave signals or reflect the signals in varying degrees back to the satellites. Calm lakes, for example, tend to bounce the microwaves away. Trees and buildings reflect more of the microwave signal back to the satellite and show up on images as a lighter color than the pure black lakes.

Scientists use the Alaska Satellite Facility data to solve dozens of problems, among them finding "ghost nets" drifting in the ocean before whales and other sea creatures become entangled in them. Arleen Lunsford of the Alaska-Pacific River Forecast Center in Anchorage uses satellite images to monitor ice sheets on the Yukon River; scientists at NASA's Jet Propulsion Laboratory used images to check out urban stormwater runoff from Los Angeles into Santa Monica Bay; UAF researchers have used the data to monitor ice "break-offs" that could strand Native hunters off Alaska's northern coast, and NASA researchers used synthetic aperture radar's ability to see through clouds to make a map of Antarctica.

For those in the Fairbanks area who want to learn more about Alaska Satellite Facility and help celebrate the 15th anniversary of those first images from north of Hudson Bay, come to the open house on Aug. 26th from 10 a.m. to 3 p.m. at the Elvey Building. It's easy to find; look for the building with the giant birdbath on top.

 

This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community.
Ned Rozell [nrozell@gi.alaska.edu] is a science writer at the institute.

 


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