This proposal improves the global ocean reanalysis (GLORE) system in support of the ncep climate prediction center (CPC) ocean monitoring and forecasting operation

GLORE is a new ocean and sea ICE data assimilation system developed through collaborations across CPC, environment prediction center (EMC) and joint center for satellite data assimilation (JCSDA), using the joint effort for data-assimilation integration (JEDI) framework. Our objectives are to (a) upgrade GLORE to replace the 20-year-old global ocean data assimilation system (GODAS) as the next CPC real-time ocean monitoring tool, and (B) improve GLORE for ocean and sea ICE initializations to advance CPC seasonal ocean forecast and sea ICE outlook. A recent CPC ocean reanalysis (1979-2022) using GLORE presented encouraging performance in many regards, as well as opportunities for further optimizations. In this project, we plan to make two well-tested optimizations to the GLORE system: (1) to widen the data insertion window for subsurface observations below 50 meters and (2) to implement the incremental analysis update (IAU) technique. The former will allow more persistent influence of the subsurface observations on the analysis, which will be most beneficial in areas of sparse measurements. The latter will reduce the model imbalance induced by data insertion, which will improve the analysis of equatorial currents. Encouraged from the results of assimilating sea ICE concentration (SIC) in GLORE, we plan to further assimilate the satellite-measured sea ICE thickness (SIT), as well as a widely used SIT analysis product. IT is expected that this effort will enhance the GLORE sea ICE analysis for both the monitoring and forecast purposes. New versions of the GLORE analyses will be produced after the optimizations and the SIT assimilation are tested respectively. A series of seasonal hindcast experiments will be conducted using the NOAA united forecast system (UFS) to evaluate the impacts of the improved ocean and sea ICE analyses on the seasonal ocean and sea ICE forecasts. This project is a joint effort between george mason university (GMU) and CPC that builds on a strong groundwork accomplished at CPC. The deliverable products of this project can contribute to the CPC operational and research activities directly. After the completion of this project, the improved GLORE will be configured in an operational environment (RL 8) and prepared for operations with regular use in ocean monitoring and seasonal forecasts/outlooks (RL 9).