ANALYSIS OF SATELLITE-DERIVED SURFACE TEMPERATURE CHANGES OF THE GREENLAND ICE SHEET, 2000-2006, USING MODIS DATA

Recent evidence shows accelerated melting of the Greenland Ice Sheet. Surface melt, which is directly related to surface temperature, may contribute more directly to accelerated disintegration of the ice sheet because of its rapid movement to the base of the ice sheet where it can allow accelerated ice flow, leading to accelerated sea-level rise. Mean, clear-sky surface temperature of the Greenland Ice Sheet was measured for each melt season from 2000 to 2005 using Moderate-Resolution Imaging Spectroradiometer (MODIS)–derived land-surface temperature (LST) data-product maps. During the period of most-active melt (May through mid-August), the mean, clear-sky surface temperature of the ice sheet was highest in 2002 (-8.29±5.29°C) and 2005 (-8.29±5.43°C), compared to a 6-year mean of –9.04±5.59°C, in agreement with recent work by other investigators showing unusually extensive melt in 2002 and 2005. Surface-temperature variability shows a correspondence with the dry-snow facies of the ice sheet; a reduction in area of the dry-snow facies would indicate a more-negative mass balance.

Recent results show large fluctuations in the early melt-season surface temperatures in the “warm” years 2002 and 2005; the surface temperatures for the 2006 melt season will be studied shortly. The early part of the 2006 melt season has been reported by field researchers to be a very warm year, with extensive surface melt. Extending the study into the 2006 melt season provides further information about interannual differences in ice-sheet surface temperatures using seven years of MODIS data. Satellite-derived surface temperatures will provide insight on possible trends in ice-sheet mass balance as satellite measurements are continued into the future.