GRACE DATA BASED ANALYSIS OF RECENT MASS VARIATION IN HIMALAYA AND GANGA PLAINS

Abstract

The twin satellite GRACE mission is a joint project of National Aeronautics and Space Administration (NASA), USA and GeoForschungZentrum (GFZ), Germany. The satellite was launched in 2002 to map the variations in the earth's gravity field with the unprecedented accuracy that was never done before. The satellite GRACE provides the monthly solutions of the gravity field to a scale of few hundred kilometers. The data has been provided in the form of the spherical harmonic coefficients up to degree and order 90 of the Release 5 data provided by the GFZ agency. The locus of the study is to find the recent mass variations in the l-limalaya Mountains and the Ganga Basin. The recent study on the Northern part of India has revealed that there is a fast decrease in the groundwater resources of the country which can lead to serious effects in the future. This study focuses on estimating the terrestrial water storage variations in the Ganga Basin using the time variable gravity field changes observed by the GRACE satellite during the time period of January 2003 to September 2012. The study includes the comparison of the GRACE based water storage estimates of the Ganga Basin with the Deutscher Wetterdienst's Global Precipitation Climatology Center (GPCC) and NASA's Global Land Data Assimilation System (GLDAS). Results show the sufficient agreement in the second half of the time period while in the first half the results show some deviation from each other. It is concluded that the total water storage in the Ganga Basin is lost at a rate of -6.960 14.85 mm/year.