Combining Different Types of Gravity Observations in Regional Gravity Modeling in Spherical Radial Basis Functions

With the increasing number of high-resolution gravity observations, which became available in the recent years, global Earth gravity models can be regionally refined. While global gravity models are usually represented in spherical harmonic basis functions with global support, a very promising option to model the regional refinements is the use of spherical radial basis functions with quasi-compact support. We use the approach of regional gravity modeling in spherical radial basis functions, with parameter estimation to determine the coefficients of the signal representation, on a test data set provided by the IAG-ICCT study group JSG0.3. We demonstrate on the data set for Europe that the approach is well-suited for different types of observations, such as terrestrial, aerial, and satellite-based measurements, as well as their combination. Furthermore, our results contribute to the study group's goal of inter-comparison of different modeling methodologies. Our regional modeling approach leads to relative errors of about 0.2-2% when compared to the validation data sets on the topography.