New Generation of Global Ocean Data Assimilation System at NCEP
The model used for the new system is the coupled model of NCEP based on the Global Forecasting System with FV3 core (GFS-FV3), the Modular Ocean Model (MOM) version 6 and the Los Alamos sea ice model (CICE5). The data assimilation system is hybrid (3DVar/EnKF), and it is based mainly on the Sea-Ice Ocean and Coupled Assimilation (SOCA) utilizing the Joint Effort for Data assimilation Integration (JEDI). The perturbations for the EnKF component are calculated by using the Universal Multi-Domain Local Ensemble Transform Kalman Filter (LETKF) algorithm. The system ingests in situ temperature and salinity and satellite SST and altimetry observations. The horizontal resolution of the GODAS is ¼ degree, with 75 vertical hybrid coordinate levels and runs in a daily cycle.
The new generation of GODAS has fundamental advantages over the operational system and produced significant improvements in the analysis of temperature, salinity, sea surface height. During this presentation, the preliminary results from the retrospective run of the system will be presented and discussed in comparison with passive observations and the current operational GODAS.