Gravimetric Geoid Modeling by Stokes and Second Helmert’s Condensation Method in Yogyakarta, Indonesia

Abstract

Since the last decade, Indonesia has continuously improved the accuracy of the national geoid model by conducting rapid gravity acquisition using airborne and terrestrial gravimetry. As gravity data have been collected thoroughly in all regions, the time has come to carry out Indonesia’s geoid modeling. We started our study by employing the Stokes and Second Helmert’s condensation method to our terrestrial gravity data in Yogyakarta, Indonesia, with a target area of 1∘× 1∘. The computation was based on the commonly applied remove-compute-restore process. We used a satellite-only geopotential model of GO_CONS_GCF_2_TIM_R6 up to degree 300 to remove and restore the long-wavelength part of the gravity field within the modeling process. Numerical results show that few cm of geoid model accuracy was achieved when we compared it to the validation points. Also, our best performance geoid is estimated to be better than the Earth Gravitational Model 2008 (EGM2008) geoid model by up to 2.8 cm in terms of standard deviation.