Comparison of different ocean tide models especially with respect to the GRACE satellte mission

Abstract

For the modeling of a static gravity field, the impact of ocean tides is subtracted from the GRACE data. Since there are more than one ocean tide model available, it is worth to learn the difference between the models and the consequence of applying different model. Three ocean tide models FES2004, EOT08a and EOT10a provided in the form of tidal maps are compared in this thesis. Based on the tidal maps, the disturbance in the potential and in the acceleration due to a single ocean tide is derived by using spherical harmonic analysis. Tools for visualization are developed to demonstrate the difference between the EOT models and FES2004 globally at a specific time point or locally at a specific site in a time period. Furthermore, a simulation of the GRACE mission and spherical harmonic analysis using the differential gravimetry approach build a closed loop simulation together, from which it can be find out, how the model difference affects the gravity field derived from GRACE data in the frequency domain.