Satellite and airborne gravimetry: their role in geoid determination and some suggestions

Abstract

This paper will cover a variety of topics. First, it will briefly overview the GRACE (Gravity Recovery and Climate Experiment) and GOCE (Gravity field and steady-state Ocean Circulation Explorer) satellite mission concepts, with a view to the improvements made (and to be made) to the global gravity field. Second, it will summarise some results of the assessment of the recent EGM2008 global gravity field model, which has a spatial resolution of about 10 km. Third, it will describe the computation and evaluation of the AUSGeoid09 model that will be released by Geoscience Australia in the very near future. All three topics will be set in the framework of the restrictions of current data and how airborne gravimetry can contribute. With the increased interest in coastal zone mapping because of threats like sea level change and tsunamis, airborne gravimetry can bridge the gap between land and satellite altimeter-derived gravity data.As such, a proposal will be made to collect airborne gravimetry in key Australian coastal zones, but preferably along the entire coastline! Another area that lacks gravity data is Antarctica, which can adversely affect global gravity field models (the polar-gap problem). Airborne gravimetry has already been used to survey the gravity field of the Arctic, so another proposal will be made to collect airborne gravity over Antarctica. Of course, both are ambitious and massive projects, but it is important to consider them as valuable applications of airborne gravimetry.