The space-wise approach for the computation of global and local gravity field solutions from NGGM/MAGIC simulated data

The space-wise approach is a methodology for processing data from satellite gravity missions with the aim of estimating the Earth gravity field. The core idea is to exploit the spatial variability and correlation of the gravity field, also considering its local inhomogeneities, to enhance the data filtering. This method fits very well with the computation of regional solutions, namely local spherical grids of some gravity field functionals using only (or mainly) the satellite observations collected over the study area. Of course, if this local estimation is systematically performed for many areas covering a whole reference sphere, a set of spherical harmonic coefficients can also be retrieved by patching the estimated local grids all together and then performing a straightforward spherical harmonic analysis.

Future satellite gravity missions, like NGGM/MAGIC or other ones based on quantum technology, are promising to provide data that will improve the accuracy and the spatial-temporal resolution of the current investigations on the time-variable part of the Earth gravity field. In the ESA-MPEF (Mission Performance Evaluation Framework) project, the space-wise approach is proposed as one of the possible strategies for the retrieval of both global and regional gravity field solutions from NGGM/MAGIC data. In this work, the processing scheme of the space-wise approach is outlined and some simulation results are shown. In particular, the focus of the simulated regional solutions is on the estimation of the total water storage anomaly for some hydrological basins of interest.