An Attempt Towards an Optimum Combination of Gravity Field Wavelengths in Geoid Computation

Abstract

AbstractThe optimum combination of gravity field wavelengths in the framework of geoid computation remains always a hot research topic. Different approaches for such a combination of the wavelengths exist. The window technique (Abd-Elmotaal and Kühtreiber, Journal of Geodesy, 77–85) has been suggested to get rid of the double consideration of the topographic-isostatic masses within the data window in the framework of the remove-restore technique. The modified Stokes’ kernel has been suggested to possibly combine the local data signals with the global geopotential earth models. Both techniques have been used in computing a gravimetric geoid for Austria. The available gravity, height and GPS data for the current research are described. The EGM96 geopotential model has been used. A broad comparison between modified Stokes’ kernel and window techniques has been carried out within this investigation in the framework of the geoid computation. The comparison is made on two different levels; the residual gravity anomalies after the remove step and the computed geoid signals before and after scaling to the GPS/levelling geoid. The results proved that the reduced gravity anomalies using the window technique are the smoothest, un-biased and have the smallest range. The modified Stokes’ kernel technique gives the best fit to the GPS/levelling derived geoid. The window technique gives, however, fairly better results than the Stokes’ un-modified kernel techniqueKeywordsModified Stokes’ kernelWindow techniqueRemove-restore techniqueGeoid determination