Data Assimilation of Ocean and Sea-ice Data for Forecast and Reanalysis with the TOPAZ System

In the frame of the European MyOcean project (www.myocean.eu.org), a newer version of the TOPAZ North Atlantic and Arctic forecasting system is being integrated in reanalysis mode over the last 20 years. TOPAZ is a data assimilative system using the Ensemble Kalman Filter (EnKF). The model has been upgraded to the newest version of the HYbrid Coordinate Ocean Model (HYCOM) with a resolution of 11-16 km, with additional features in the snow module of the sea-ice model, and river run-off based on a hydrological model. The EnKF is assimilating satellite altimeter track, sea ice concentration and drift velocity, satellite SST, and T-S profiles from Argo buoys and gliders. Finally, ongoing efforts are directed towards the assimilation of ocean color data in the coupled HYCOM-NORWECOM model. The forecasts and reanalysis data services are following a free and open data policy. The data are used by the environment agencies, weather services, the oil and gas industry, and not the least for planning research cruises.

The presentation will show the impact of the different data sources in the assimilation system and address the issues of physical consistency and accuracy of the data assimilation method.