Based on two types albedo data from Landsat TM image acquired on August 2nd in 2007 and MODIS daily snow albedo products (MOD10A1) during the period of 2000-2009, the temporal and spatial characteristics of albedo on the Dongkemadi Glacier are analyzed in this research. The following conclusions can be drawn: 1) Owing to the limitation of spatial heterogeneity and the current retrieving method, albedo values derived from Landsat TM images and MOD10A1 products have a certain bias (RMSE=0.046, R²=0.77 and RMSE=0.088, R²=0.68, respectively). Nevertheless, they generally can be used for the research on spatial-temporal variations of glacier albedo. 2) Spatially, albedo on the Dongkemadi Glacier increases with altitude, ranging from 0.17～0.74. Affected by topography factors, albedo at the same altitude belt appears great discrepancy, which at the zones around the snow line varies obviously most of all. 3) Temporally, albedo varies greatly owing to the effect of terrain, and varies with the season change significantly as well. Seasonally, albedo is the maximum in autumn, begins to reduce in winter, reaches the minimum at the ablation period in summer (July to August), and increases again after the summer ablation period. During the period of 2000-2009, albedo of the glacier appeared an obvious fluctuation, and decreased slowly; this trend was mainly caused by the changes of the total snowfall and the surface of the glacier. Ignoring the variation of annual snowfall, glacier albedo in the summer ablation period showed a decreasing trend during 2000-2009, with a rate of -0.0083·a^-1, which was attributed to the increasing air temperature in summer and the ice surface pollution year by year.

Download