HR: 1340h
AN: C23A-1166    [Abstracts]
TI: Assessment of Surface Facies on Greenland Ice Sheet Using ERS-1/2 C-band Scatterometer Data
AU: * Hussein, K
EM: khalid.hussein@colorado.edu
AF: Unversity of Colorado, UCB 216, Boulder, CO 80309 United States
AU: Steffen, K
EM: konrad.steffen@colorado.edu
AF: Unversity of Colorado, UCB 216, Boulder, CO 80309 United States
AU: Huff, R
EM: russell.huff@colorado.edu
AF: Unversity of Colorado, UCB 216, Boulder, CO 80309 United States
AB: Three ERS-1/2 C- band scatterometer images of the Greenland Ice Sheet (GIS) acquired in late September representing the years 1992, 1996, and 2000 are utilized to investigate and identify different surface properties and facies on the GIS. The images are and used to, delineate the ice sheet facies, assess their sizes and compare these to Benson's map. The possibility that climatological parameters such as annual temperature and annual accumulation define the boundaries of the facies on the GIS annually is also examined. The processed images demonstrate a transitional zone between the dry snow and the percolation facies, and a distinct boundary between percolation and soaked snow facies. The dry snow facies, percolation facies, transitional zone, and soaked and ablation facies occupy an area of about, 40%, 30%, 12%, and 18%, of the total surface area of the GIS, respectively. Comparison of the boundaries of the dry snow facies defined in the present study with the map of Benson (1962) reveals that the boundaries are located to the west and the size of the dry snow facies has increased compared to Benson's map. The -25§ C annual mean surface temperature isotherm delimits the dry snow facies from the south, southeast and the west (north of the latitude 74.0§ N). However in the west (south of latitude 74.0§ N) the -22.5§ C mean annual temperature isotherm defines the dry snow facies. The -22.5§ C mean annual temperature isotherm delineates the percolation facies from the west and northeast, while the -25.0§ C isotherm marks it from the south and southeast. The analysis and the results achieved in this study reveal that the scatterometer images can be used for the identification and demarcation of ice sheet and glacier facies, as well as for estimating their areas. Hence the boundaries between the dry snow and percolation facies are defined by specific contours of annual mean surface temperature and other parameters. Changes in the boundaries between the dry snow and the percolation facies can be used as an indicator of climate change over the GIS.
DE: 0700 CRYOSPHERE (4540)
DE: 0726 Ice sheets
DE: 0740 Snowmelt
SC: Cryosphere [C]
MN: Fall Meeting 2005