Comparison and fusion of satellite, airborne, and terrestrial gravity field data using wavelet decomposition

A multiresolution wavelet analysis of gravity datasets obtained from satellite, airborne, and terrestrial platforms was conducted to estimate their spectral differences and develop a fused free-air gravity model. In this study, fifth-generation Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite model (DIRR5 and TIMR5), airborne, and terrestrial gravity data were compared to estimate their differences within various spectral bands using wavelet decomposition. The datasets were combined in a two-dimensional approximation while taking into account their strongest spectral content to derive a fused gravity model that shows improved long and medium wavelengths over those of the original terrestrial gravity dataset. The studies were focused on two distinct areas, namely, the relatively smooth gravity field along the coast of the southeastern United States and the northern Gulf of Mexico and the highly variable gravity field of eastern Alaska. Results show that changes brought by satellite and airborne data in areas where the gravity field is smooth (southern United States) were negligible (0.1-0.2 mGal). However, in areas where the gravity field is more variable and the terrestrial data density is lower, the contribution of the airborne gravity and satellite data was increasingly significant on the order of several milligals. Results indicate future possibilities in predicting the necessity and contribution of airborne data based on the presented regional analysis scheme.