Gravity inversion using point mass distribution

Abstract

Global climate change is a serious problem influencing our environment and Greenland ice mass loss is one of the phenomena of climate change. Every year hundreds of gigaton of ice melts and flows into the ocean, which causes the rising of the global sea level. This work is to estimate the ice mass loss of Greenland with the gravitational signals derived from GRACE (Gravity Recovery And Climate Experiment) data. The point-mass modelling applied in this work enables us to infer the mass variations on the Earth’s surface from the gravitational signals at satellite altitude. In order to solve the derived observation equations and stabilize the ill-posed problem, we apply the least-squares adjustment with Tikhonov regularization. Our simulation studies and real data experiment show that point-mass modelling provides both rational mass variation results and high-resolution spatial mass variation patterns. The numerical results indicate that on average near 300 km3 of ice melts and flows into the ocean from Greenland every year.