Improvements to a global ocean data assimilation system through the incorporation of Aquarius surface salinity data

The impact of using sea surface salinity (SSS) data derived from the Aquarius satellite within a global ocean data assimilation system is investigated. In the central-eastern North Pacific, the more realistic SSS structures introduced by the Aquarius data also influence the salinity, temperature and potential vorticity fields obtained in the subsurface layer via enhanced mode-water formation. Around the Indonesian maritime continent, the Aquarius data assimilation leads to salinity distributions which are closer to buoy observations, while in the region of the Amazon River plume, subsurface temperatures are improved following a better reproduction of the low-salinity plume in the surface layer. The SSS model biases are also reduced in the eastern equatorial Pacific and in the Arctic Ocean, although our data are limited in number and accuracy at high latitudes. These results indicate the importance of Aquarius data in deriving improved representations of the global ocean from dynamical models.