Tretyak N. Modeling of the gravity field and topography of the ocean in the region of Antarctica

The thesis is devoted to the modeling of the gravity field and topography of the ocean in the region of Antarctica. The gravimetric data for the period of more than ten years were taken as the initial data for mathematical processing using sequentional multipole analysis in the remove-restore technique for modeling the regional gravity field up to 1200 degree/order. Independent validation of the SST model together with the gravimetric quasigeoid has led to the average differences of 10 cm level that reflects a quality of solution for such region as Antarctica. The values of the normal heights were calculated for the points with known geodetic heights on the continent, using a local quasigeoid model. There were solved such problems as the estimation of the quality of the DTM GEBCO model for Antarctic region and the computation of the mean regional value for the gravity potential as the second level tasks in this work. The comparison of DTM GEBCO and computed normal heights for well-determined GPS-sites led to the low accuracy of this DTM and to the application of the Molodensky formulae for further covering the Antarctic area by normal heights. The altimetry-gravimetric quasigeoid solution was selected for further computation of the gravity potential W0 for the Antarctic area. The difference between global and local values of the gravity potential is on the 0.7 m level. The main conclusion is that the combined usage of the models of topography of the ocean and local quasigeoid model can lead one to the practical realization of the vertical reference system which is connected to the regional gravity field and the gravity potential value.