Comparison of ASTER GDEM and SRTM DEM in deriving the thickness change of Small Dongkemadi Glacier on Qinghai-Tibetan Plateau

As we know, SRTM (Shuttle Radar Topography Mission) DEM has been widely used to evaluate the multi-decadal elevation changes of mountain glaciers. Recently, a new global elevation dataset known as GDEM, based on the ASTER satellite imagery has also been released. In this paper various kinds of data on SDG(Small Dongkemadi Glacier) were collected to evaluate the potential of GDEM used in this field, including the GDEM, SRTM DEM, topographic map for 1969 and Landsat ETM+ image for 2000. The elevation change from GPS survey data (2007) and DEM(1969) on SDG is used to validate the results here. The comparison analysis shows the thickness change detected by SRTM DEM is consistent with the GPS measurements, however, the result from ASTER GDEM is far away from the field work on SDG, although the overall distribution is right. The experiment results will cause our serious attentions to the usage of GDEM in glacial field.