GOCE Gravity Gradients and the Earth's Time-varying Gravity Field
Bouman, Johannes1; Visser, Pieter2; Fuchs, Martin1; Broerse, Taco2; Haberkorn, Christoph1; Lieb, Verena1; Schmidt, Michael1; Schrama, Ernst2; van der Wal, Wouter2

The objective of the GOCE mission is to map the Earth's mean gravity field with unprecedented accuracy down to spatial scales of 80 km. Nevertheless, the longer than planned observation period, the satellite's low orbit and the high accuracy of the gravity gradiometer may all contribute to GOCE's ability to see gravity variations with time. We present an ESA STSE feasibility study in which the signal due to Antarctic ice mass changes and the Japan-Tohoku earthquake 2011 is forward modelled in terms of gradient signal at GOCE altitude. We present our tailored analysis of the GOCE data and the comparison with the forward models. We address the effect of errors in the background models, e.g. to account for Glacial Isostatic Adjustment and Dynamic Ocean Topography. We will show that GOCE complements the accurate long wavelengths of GRACE by adding spatial detail, whereas the temporal resolution is 4 months or more.