Satellite Gravity Incorporating Higher Frequency Signals from AltiKa Data – Next Stage in Altimeter Gravity Enhancement

Gravity calculated from satellite altimeter data has improved in resolution, accuracy and reliability over the years since Haxby's 1985 map of the world's oceans derived from SeaSat. Initial improvements were based on enhanced coverage. SeaSat had a track spacing of ~125 km - an exact repeat mission (ERM), but by the mid 1990s track spacing of 3–4 km was available from the geodetic missions (GMs) of ERS-1 and Geosat. The next improvements were based on re-tracking altimeter waveforms. This led to improvements in along-track resolution of the sea surface and the derived gravity. Since 2010, new GMs of CryoSat-2 and Jason-1 have provided a vast quantity of additional data, but also a wider range of track orientations has allowed gravity with improved reliability - fewer track-aligned artefacts. CryoSat-2 had two additional modes, SAR and SARIn, which provide data closer to coasts, but are not available globally. Newly available Geodetic Mission AltiKa data has higher frequency signals which should yield a more accurate and higher resolution sea surface as well as less coastal interference. In this presentation we demonstrate how we have addressed the challenge of incorporating these AltiKa data with other satellites to further improve the satellite gravity data.