Evaluating EGM2008 over East Antarctica

Abstract

The release of EGM2008 and associated products such as grids of mean dynamic ocean topography offer the possibility of utilising the extensive historical record in Antarcticawith today's modern satellite sensing techniques. In this study, we use data acquired at the Mawson, Davis, Casey and Scott and McMurdo stations in East Antarctica to investigate the performance of EGM2008 over this region. EGM2008 over Antarctica is entirely dependent on the EGM2008-adopted global GRACE satellite-derived gravity field. This is in contrast to most other regions of the Earth, where there are also contributions from terrestrial gravity and/or altimeter satellites. We determine, over East Antarctica, and at our four test sites that EGM2008 should be used with caution when precisions better than one metre are required. The precisions at the test sites are better than this, but the evidence is that the four test sites are probably not representative of the large area of East Antarctica they are being forced to represent. Notwithstanding any of the above, EGM2008 represents a significant step forward in East Antarctica and that the use of test stations and regions where there is little or no complementary data is a valid method of investigating the performance of the model.