USE OF THE GOCE MISSION FOR THE DETERMINATION OF SEA LEVEL AND ANTARCTIC CIRCUMPOLAR CURRENT

We will use data from the GOCE satellite missions in order to determine structure and transport of the Antarctic Circumpolar Current and the Weddell Gyre. This will be the basis for the calculation of large-scale exchange processes between the Pacific, the Atlantic and the Indian Ocean. Our aim requires a detailed and exact description of the ocean circulation and its associated transports of heat and tracers which we propose to obtain by assimilation of highly accurate sea level data in an ocean circulation model. Data assimilation combines a set of diverse information that stems from oceanographic in situ measurements, remote sensing data, altimeter values and geoid models on the one hand with modelled ocean dynamics on the other hand. We derive a dynamically consistent, mass- volume-, heat- and salt-conserving solution of the ocean model. It describes the evolution of the sea level, currents and water mass distributions in accordance with the measurements and important transports and features of the global ocean circulation are derived. STATUS OF RESEARCH The determination of the transport of the Antarctic Circumpolar Current causes problems in ocean models. A widespread use is the prescription of its value at Drake Passage. Alternatively an implicit prescription by tuning model friction, coastlines or bathymetry is commonly used. In this context inverse models are similar with the exception of box-inverse models. However, due to their very poor resolution only integral properties form reliable results. The spatial structure remains unresolved. The use of satellite altimetry to derive transport values sometimes leads t