Towards an Operational Hybrid Global Ocean Data Assimilation System at NCEP

A Hybrid 3d-Variational (3DVar) / Local Ensemble Transform Kalman Filter (LETKF) data assimilation (DA) system has been implementated at the NOAA National Centers for Environmental Prediction (NCEP). A 21-Year reanalysis has been performed using this system, assimilating observed temperature and salinity profiles. A second reanalysis has been performed adding satellite altimetry. This DA system is currently being tested for operational use by the Climate Prediction Center (CPC) and for a prototype next-generation Climate Forecast System (CFSv3). Strongly coupled DA is being implemented with the coupled system, for example allowing atmospheric observation innovations to influence the ocean state at the time of the analysis.