Time-variable satellite gravity models application for the development of an archipelagic geoid-based height system

The practicality of gravimetric methods for heighting depends on the reliability of the geoid model. This paper covers the evaluation of selected Global Geopotential Models (GGM) over the Philippines and the Philippine Geoid Model (PGM2016.66), and an approach to capture temporal variations of the geoid using satellite-based information. Geoid profiles and statistical measures show that points clustered in the northern latitudes and western longitudes have smaller residuals. Based on the GGM histograms, EGM2008 is the best suited to the Philippine terrestrial gravity data, followed by GECO and EIGENGL04C. An analysis of temporal GGMs for detection of geodynamic effects (CSR, GFZ, JPL — monthly and weekly; ITSG — daily) showed a striping error pattern that is addressed in this paper. A correction procedure using decorrelation methods and Gaussian filters was applied. The hydrological effect to the geoid change rates is minimised by using Global Land Data Assimilation System (GLDAS).