HR: 10:50h
AN: C22A-03    [Abstracts]
TI: Southern Alaska Glaciers: Spatial and Temporal Variations in Ice Volume
AU: * Sauber, J
EM: jeanne@steller.gsfc.nasa.gov
AF: Laboratory for Terrestrial Physics, NASA's Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Molnia, B F
EM: bmolnia@usgs.gov
AF: U.S. Geological Survey, 926A National Center, Reston, VA 20192 United States
AU: Luthcke, S
EM: Scott.B.Luthcke@nasa.gov
AF: Laboratory for Terrestrial Physics, NASA's Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Rowlands, D
EM: David.D.Rowlands@nasa.gov
AF: Laboratory for Terrestrial Physics, NASA's Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Harding, D
EM: David.J.Harding@nasa.gov
AF: Laboratory for Terrestrial Physics, NASA's Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Carabajal, C
EM: Claudia.C.Carabajal.1@gsfc.nasa.gov
AF: Laboratory for Terrestrial Physics, NASA's Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Hurtado, J M
EM: hurtado@geo.utep.edu
AF: Dept. of Geological Sciences, University of Texas, El Paso, El Paso, TX 79968 United States
AU: Spada, G
EM: spada@fis.uniurb.it
AF: Institute of Physics, Urbino University, Urbino, PU 61029 Italy
AB: Although temperate mountain glaciers comprise less than 1% of the glacier-covered area on Earth, they are important because they appear to be melting rapidly under present climatic conditions and, therefore, make significant contributions to rising sea level. In this study, we use ICESat observations made in the last 1.5 years of southern Alaska glaciers to estimate ice elevation profiles, ice surface slopes and roughness, and bi-annual and/or annual ice elevation changes. We report initial results from the near coastal region between Yakutat Bay and Cape Suckling that includes the Malaspina and Bering Glaciers. We show and interpret ice elevations changes across the lower reaches of the Bagley Ice Valley for the period between October 2003 and May 2004. In addition, we use off-nadir pointing observations to reference tracks over the Bering and Malaspina Glaciers in order to estimate annual ice elevation change. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Shuttle Radar Topography Mission (SRTM) derived DEMs are used to estimate across track regional slopes between ICESat data acquisitions. Although the distribution and quantity of ICESat elevation profiles with multiple, exact repeat data is currently limited in Alaska, individual ICESat data tracks, provide an accurate reference surface for comparison to other elevation data (e.g. ASTER and SRTM X- and C-band derived DEMs). Specifically we report the elevation change over the Malaspina Glacier's piedmont lobe between a DEM derived from SRTM C-band data acquired in Feb. 2000 and ICESat Laser #2b data from Feb.-March 2004. We also report use of ICESat elevation data to enhance ASTER derived absolute DEMs. Mountain glaciers generally have rougher surfaces and steeper regional slopes than the ice sheets for which the ICESat design was optimized. Therefore, rather than averaging ICESat observations over large regions or relying on crossovers, we are working with well-located ICESat footprint returns to estimate glacier ice elevations and surface characteristics. To obtain the optimal ICESat results, we are reprocessing the ICESat data from Alaska to provide a well-calibrated regional ICESat solution. We anticipate that our ICESat results combined with earlier data will provide new constraints on the temporal and spatial variations in ice volume of individual Alaskan mountain ranges. These results allow us to address how recent melting of the southern Alaska glaciers contribute to short-term sea-level rise. Our results will also enable us to quantify crustal stress changes due to ice mass fluctuations and to assess the influence of ice mass changes on the seismically active southern Alaskan plate boundary zone.
DE: 8102 Continental contractional orogenic belts
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 1224 Photogrammetry
DE: 1620 Climate dynamics (3309)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting