Analysis of the melting glaciers in Southeast Tibet by ALOS-PALSAR data

Abstract

Global warming has resulted in the melting of glaciers in the southeastern region of Tibet. This study used the InSAR time series obtained from ALOS PALSAR data to investigate the melting glacier over Southeast Tibet during 2007 - 2010 with the small baseline subset (SBAS) technique. Additionally, GRACE (Gravity Recovery and Climate Experiment) gravity field model issued by the Center for Space Research (CSR) was used to extract the equivalent water height (EWH) with the deduction of glacial isostatic adjustment (GIA). The results revealed that the monitoring results by InSAR were basically consistent with the EWHs from GRACE. The glacier deformation in the study area presents a downward trend overall. From the InSAR measurements, a 900-km2 area within the belt subsided -1.6 cm yr-1 during 2007 - 2010, and the subsidence exceeded -24 cm yr-1 in some regions. Considering GRACE products are comprehensive with large space scale monitoring results, the rate is about -0.01 cm yr-1 from GRACE. With the variations of glacier shape obtained from MODIS (moderate-resolution imaging spectroradiometer) data, the changing rate of surface temperature was about 0.014°C yr-1. The surface temperature change is negatively correlated with the rate of the glacial subsidence with the correlation coefficient of -0.237, which reflects that the melting glacier is influenced by the temperature rising to a certain extent.