Research on the effects of isostasy in gravity gradient map modelling

The current method of gravity gradient map modelling is based on digital elevation model, the effects of isostasy in gravity gradient map modelling are researched and analyzed in this paper, and a novel method of modelling gravity gradient map was presented. The current isostasy theory shows that the density of crust changes with elevation, so assigning a constant value to landform´s density is not accurate enough. At first, two kinds of isostasy model are analyzed, and on the basis of isostasy model, the gravity gradient map is modeled by using improved landform density model. Then experimental results shows that Pratt model impose on much more effects on gravity gradient map than Airy model. Consider the two models´ effects in gravity gradient map modelling, Pratt Model could correct an average error of 2.0% in the ocean area, Airy Model could correct an average error of 0.000085% in the land area.