Towards 1 MilliGal Global Marine Gravity Accuracy from CryoSat-2, Jason-1, and Envisat

Marine gravity from satellite altimetry has become a primary tool for investigating the tectonics of the remote ocean basins as well as unexplored continental margins. Gravity field accuracy depends on four factors: spatial track density (especially near coastlines); altimeter range precision; diverse track orientation; and the accuracy of the coastal tide models. Recently three new non-repeat altimeter data sets have become available (CryoSat-2, Jason-1, and Envisat) resulting in a factor of 2-4 improvement in the global marine gravity field. Most of the improvement in the altimeter-derived gravity field occurs in the 12 to 40 km wavelength band, which is of interest for investigation of structures as small as 6 km. The current version of the altimeter-derived gravity field has an accuracy of 1.7 mGal in the Gulf of Mexico and 2.4 mGal in the Canadian Arctic. Unlike terrestrial gravity where coverage is uneven, these accuracies are available over all marine areas and large inland bodies of water so this gravity provides an important resource for exploring the deep ocean basins. At the meeting we will present the latest gravity model based on 3 years of CryoSat-2 data and the complete Jason-1 geodetic mission and will discuss new tectonic features that appear in the higher resolution model.