Terrestrial Water Storage Changes of Permafrost in the Three-River Source Region of the Tibetan Plateau, China

Changes in permafrost influence water balance exchanges in watersheds of cryosphere. Water storage change (WSC) is an important factor in water cycle. We used Gravity Recovery and Climate Experiment (GRACE) satellite data to retrieve WSC in the Three-River Source Region and subregions. WSC in four types of permafrost (continuous, seasonal, island, and patchy permafrost) was analyzed during 2003-2010. Theresult showed that WSC had significant change; it increased by 9.06 +/- 0.01 mm/a (21.89 +/- 0.02x10(9)m(3)) over the Three-River Source Region during the study period. The most significant changes of WSC were in continuous permafrost zone, with a total amount of about 13.94 +/-+0.48x10(9)m(3). The spatial distribution of WSC was in state of gain in the continuous permafrost zone, whereas it was in a state of loss in the other permafrost zones. Little changes of precipitation and runoff occurred in study area, but the WSC increased significantly, according to water balance equation, the changes of runoff and water storage were subtracted from changes of precipitation, and the result showed that changes of evaporation is minus which means the evaporation decreased in the Three-River Source Region during 2003-2010.