The optimization of marine geoid model from altimetry data using Least Squares Stokes modification approach with additive corrections across Malaysia

Abstract

ABSTRACT Due to the high cost and time constraints, geoid and gravity surveys utilizing airborne and shipborne surveys can only be implemented in marine areas with limited coverage. Satellite altimeter has become an essential tool for global geoid and gravity field recovery. With approximately 60% observation coverage of the Earth’s surface for ocean height, researchers can replace conventional marine geoid models by conducting faster surveys over massive areas at a minimal cost. This study attempts to develop a marine geoid model from multi-mission satellite altimetry along-track data using the Least Squares Modification of Stokes with Additive Corrections. The gravity anomaly has been computed using Gravity Software, and the planar Fast Fourier Transformation method has been applied. The evaluation, selection, blunder detection, combination, and re-gridding of the altimetry-derived gravity anomalies and Global Geopotential Model data are demonstrated. The cross-validation approach has been employed in the cleaning and quality control the data using the Kriging interpolation method. The optimal condition modification parameters of the spherical cap, terrestrial gravity data error, and correlation length have also been applied. Then, the additive corrections based on Downward Continuation, Atmospheric Effects, and Ellipsoidal corrections were combined with the estimated geoid to provide a precise marine geoid over the Malaysian seas. The findings have been evaluated with the MyGeoid17 model from the Department of Survey and Mapping Malaysia. The validation yields satisfactory results with accuracy up to a centimetre level. Hence, the marine geoid model can be utilized for orthometric height determination in marine areas over the Malaysian seas.