ESTIMATION OF GLACIER MASS CHANGES IN HIMALAYA ALPINE REGION INFERRED FROM GRACE SATELLITE GRAVIMETRY

Abstract

The disappearing of glaciers in Himalaya alpine region, in where hundreds of millions of people rely on melting glaciers for water, has been reported by recent studies. However, the estimation of change in glacier mass still has a significant challenge because of a limited observational methodology to understand hydrological processes in Himalaya region. In this study, we estimate the ice loss rate for the Himalaya alpine region for the period January 2003 through December 2008, mainly using terrestrial water storage (TWS) variations observed by the Gravity Recovery and Climate Experiment (GRACE). To separate the effect of the other TWS components, simulated soil moisture, snow mass and river storage are calculated by using the Minimal Advanced Treatment of Surface Interaction and Runoff (MATSIRO) land surface model (LMS). The methodology using GRACE data and LMS result is similar to one of previous studies. In addition, we also use groundwater withdrawal data, and our estimated glacier mass change is compares with glacier model (HYOGA) results. Finally, it is estimated that the melting rate of the glacier mass over target region is approximately 4.7 Gt/year. Although we believe that our methodology is the newest comparing previous one, our estimated value is much underestimated than HYOGA results. Our methodological experience and information will be helpful to better understand glacier mass change.