Modelovanie regionálneho tiažového poľa z meraní družicovej misie GOCE

In this contribution we discuss a regional recovery of gravity disturbances at the mean geocentric sphere approximating the Earth over the area of Central Europe from satellite gravitational gradients. The main aim of the presented study is to investigate three numerical approaches for reducing the far zone effect for solving an inverse problem. The initial approach is based on the modification of the integral formulas, i. e., we are solving individually the near- and distant-zone contributions. The second approachis a simple modification of the first scenario by reducing measured gravitational gradients for gravitational effects of topographic masses. In the last approach called herein as the third scenario, we apply additional modification by reducing gravitational gradients for the reference global geopotential model. In all three approaches we estimate the gravity disturbances from each of the four well-measured gravitational gradients separately as well as from their combination. Our regional gravity field solutions are based on the GOCE EGG TRF 2 gravitational gradients collected within the period from November 1 2009 until January 11 2010. As an overall reference we choose EGM2008. The best fit, in terms of RMS (4.4 mGal), is achieved using a second approach and Tzz.