NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., is designing sophisticated radar receiving system to help image and track Arctic ice flows and the remote areas of Alaska and its surrounding seas.

The overall system, including 10-meter receiving antenna, called the Alaska SAR Facility, will be at the University of Alaska Fairbanks (UAF), and will be implemented by JPL and managed by the Geophysical Institute of the university.

The system initially will be capable of receiving signals from three satellites carrying synthetic aperture radar (SAR) which penetrates thick cloud cover and produces data for high resolution images.

The facility is scheduled to be fully operational in time for the April 1990 launch of the European Space Agency satellite called E-ERS 1. The facility also will receive data from the Canadian-led multinational Radarsat satellite which involves participation of the U.S., Great Britain and Germany, and from Japan's J-ERS 1 satellite.

In paper describing the system, JPL scientist Dr. Frank Carsey and others said the polar oceans and the ice packs have significant effect on the global climate system. They are sites of great heat loss because of the large temperature differences between the cold polar atmosphere and the relatively warm oceans.

The basic information to be extracted from SAR data is the description of the ice pack in terms of ice type, floe size, open water distribution and the motion of the ice.

SAR also is able to look at landforms in the Arctic irrespective of sunlight or weather, which have been limiting factors in high-altitude remote sensing in the past.

The facility also will provide geological studies of all of Alaska, western Canada and much of eastern Siberia. The scientists said that imaging radar is strongly sensitive to water boundaries and soil moisture and will provide data for calculating snowcover conditions, stored water and the volume of runoff.

Other applications include vegetation cover studies and oceanography. Additionally, studies are being designed to see if SAR-based observations will help evaluate navigation hazards in icy waters and the risk to offshore structures of ice pack movement.

In January 1986, an agreement was reached between NASA and ESA for direct reception of E-ERS 1 data at the Fairbanks facility; similar agreement was signed with Japan's space agency in January, 1988. The Receiving Ground System with its antenna and recording equipment will be mounted on the 8th floor of the Geophysical Institute building on the UAF campus.

Two X-band telemetry channels will be provided for reception of real-time SAR data from the satellites with maximum telemetry rate of 105 million bits per second. The facility also will have an S-band receiver for autotracking the satellites.

The system will process data at rate of about one- fourth real time by using design modified from the Magellan spacecraft instrument developed to image and map most of the planet Venus in the early 1990s.

The facility's Archive and Operations System will work with the NASA Ocean Data System network and will provide images in response to user requests.

NASA has assembled an ad hoc team of investigators, cochaired by project scientists from JPL and the University of Alaska, to assist in the development of the facility.

The Alaska SAR Facility effort is collaboration among University of Alaska, JPL, NASA and the European Space Agency to fully exploit E-ERS 1 data.

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