Ice motion mapping in Antarctica with Envisat ASAR and ALOS PALSAR
(1) JPL / UC Irvine, 4800 Oak Grove, Pasadena CA 91109, United States
Satellite radar interferometry is a very useful tool to measure ice motion in Greenland and Antarctica and help determine their state of mass balance and evolution in response to climate change. Initial research efforts started with the ERS-1/2 tandem campaign of 1995-1996 have been pursued with Radarsat mapping campaigns of 1997 and 2000, with great success, including the first comprehensive maps of coastal flow. New satellites are now available, and existing satellites have adapted their mission plan to help cryosphere studies. In early 2007, ESA adopted a special interferometry campaign of Envisat ASAR in late spring of 2007 with short interferometric baselines, horizontal receive and transmit polarization, and comprehensive coverage of Antarctica and Greenland for ice motion mapping. We processed lots of these data in the Antarctic Peninsula and in the Amundsen sea sector of West Antarctica. These represented the first C-band HH-pol data acquired in the austral winter, at a time when we would expect the least change in surface properties that could affect the coherence of the radar signal. We compare the results with data acquired prior to the campaign, when the baselines were much larger, as well as with historical data on ice velocity. Similarly, ALOS PALSAR started its operation in 2006, at L-band frequency and acquired data over the Antarctic. A special campaign started a few weeks ago to cover Antarctica during three consecutive cycles. L-band offers longer times of coherence over snow and firn which make it superior in areas of rapid surfacial changes. Examples of that will be shown in the Getz Ice Shelf sector of West Antarctica. A comparison of these results with ERS-1 data from 1996 shows very little change in speed in this sector.
This work was performed at Caltech's Jet Propulsion Laboratory and the University of California Irvine under a contract with the National Aeronautics and Space Administration's Cryosphere Science Program.
Note: to be presented no earlier than tuesday afternoon. thanks.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,