Ocean data assimilation of remotely sensed observations in the GEOS-5 coupled system

The GMAO Ocean Data Assimilation System (GMAOodas) is a flexible sequential data assimilation software that can assimilate a wide variety of oceanographic observations, including remotely sensed data such as sea level anomaly (SLA), sea surface temperature (SST) and sea surface salinity (SSS). While the importance of constraining ocean models to remotely observed SLA and SST has been widely recognize by the community, the impact and possible benefits from the assimilation of Aquarius SSS is mostly speculative. We will present some of the technical aspects of assimilating remotely sensed surface observations, including the estimation of model and observation biases and the different methods of multivariate projection of surface data throughout the water column. The benefits and limitations of assimilating Aquarius SSS are investigated using data withholding experiments and analyzing the corrected air-sea fluxes induced by the assimilation of SSS only.