Effect of Isostatic Masses in the Framework of the Window Remove-Restore Technique

Abstract

Within the window remove-restore technique (Abd-Elmotaal and Kühtreiber, 2003), the effect of the topographic-isostatic masses is removed from the source free-air gravity anomalies using high-resolution Digital Terrain Models (DTMs) and a terrain correction software, e.g., TC-program (Forsberg, 1984). A harmonic analysis of the topographic-isostatic masses is then applied to compute the effect of the topographic-isostatic masses over the data window to adapt the used geopotential model, in order to avoid a double consideration of their contribution. In this study, it is intended to use only the topographic masses in the window remove-restore technique and to compare the results with the case of using the topographic-isostatic masses. This comparison allows estimating the effect of the isostatic masses in the framework of the window remove-restore technique. The quantification of the effect is done for two mountainous regions, the Alps in Austria and the Rocky Mountains region in Colorado. The comparison is performed at two levels: reduced anomalies and computed geoidal heights. The results demonstrate the impact of the isostatic masses in window remove-restore technique and are discussed in detail.