Community Service and User Support for the Gridpoint Statistical Interpolation (GSI) Data Assimilation and Analysis System

The Gridpoint Statistical Interpolation (GSI) system is a unified variational data assimilation and analysis system for both global and regional applications. It is currently used as a data assimilation system by various operational centers, including the National Oceanic and Atmospheric Administration (NOAA) (e.g., Global Forecasting System (GFS), North American Mesoscale (NAM) system, the Hurricane WRF (HWRF), and the RAPid Refresh (RAP) system), the National Aeronautics and Space Administration (NASA) (Goddard Earth Observing System (GEOS) Model), and the Air Force Weather Agency (AFWA). This analysis system is also used to generate certain analysis products, such as output from NOAA's GFS reanalysis and the Real-Time Mesoscale Analysis (RTMA) (e.g., 2m temperature, 10m winds gust, surface pressure and surface visibility). GSI can also be used to generate analyses for climate studies (e.g., ozone and sea surface temperature (SST) analyses) or assimilate non-'traditional' fields (e.g., aerosol data assimilation) for air quality studies (e.g., dust storms). Lately, an effort was initiated to use GSI for data assimilation throughout the entire atmosphere. One example of such an effort is the development of a data assimilation system for the Whole Atmosphere Model (WAM) at NCEP. Over the past few years, GSI has been transitioned to a community resource through a joint effort led by the Developmental Testbed Center (DTC), in collaboration with the National Centers for Environmental Prediction (NCEP) Environmental Modeling Center (EMC) and other GSI partners. The DTC is a distributed facility with a goal of serving as a bridge between the research and operational communities by transitioning the operational capability to a community resource and committing the contributions from the research community to the operational repository. The DTC has hosted four Community GSI tutorials and released five versions of the community GSI system with a corresponding User's Guide. The DTC has built and continues to maintain a community GSI User's Page to provide GSI code, documentation, and on-line tutorials for the research community. The DTC staff has been providing support to GSI users through the GSI help desk since the release of version 1 of the community code in 2009. This paper will briefly describe the GSI system and emphasize the GSI community services and support available from the DTC and other developers.