5A.8 DTC GSI data assimilation system support and testing activities: 2013 annual update

Shao, Hui, National Center for Atmospheric Research (NCAR), Ming Hu, National Oceanic and Atmospheric Administration (NOAA), Chunhua Zhou, Kathryn Newman, Mrinal K. Biswas, Don Stark, NCAR, Ligia Bernardet, NOAA, Mingjing Tong, and John Derber, National Centers for Environmental Prediction

The Developmental Testbed Center (DTC) has been providing community support of the Gridpoint Statistical Interpolation (GSI) Data Assimilation (DA) system since 2009. The GSI and GSI based hybrid variational-ensemble (GSI-hybrid) systems are operational DA systems in various national research and forecast centers, including the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA). In collaboration with the GSI code developers, the DTC also conducts testing and evaluation of the GSI system, focusing on individual code changes, and provides a rational basis to the operational centers and research community. Lately, the DTC started to work with distributed teams on developing and testing a GSI-hybrid system for regional applications, particularly for tropical storm forecasts. This paper will be an overall summary of the latest work being done by the DTC data assimilation team, giving an annual update on the GSI system code changes. Included also is an introduction of the testing experiments performed using the developmental regional GSI-hybrid system and the latest results. These experiments were conducted to test different components of the system, e.g., background error generation methods and impacts, GSI-hybrid tests for tropical storm forecasts, etc.