Assimilation of SEVIRI Radiance Data in NCEP NAMRR System

A summary of recent research results of evaluating the assimilation of radiance products from Meteosat-9 SEVIRI (Spinning Enhanced Visible and Infrared Imager) observations into an hourly-updatd version of NCEP's North American Mesoscale (NAM) forecast system will be presented. As a geostationary satellite, Meteosat-9 is positioned at 0 degrees and provides full disc imagery every 15 minutes over the Atlantic Ocean, Europe and Africa. In order to get the most complete use of SEVIRI observations the hourly-updated NAM, known as NAM Rapid Refresh (NAMRR), was placed over SEVIRI's coverage area (i.e. the Atlantic Ocean, Europe and Africa). SEVIRI, and other satellite radiances (AMSUA, AMSUB, HIRS4, AIRS, MHS, IASI), as well as conventional observations are assimilated in the NAMRR system with 12 km model resolution. In order to evaluate the impact of SEVIRI data, month-long experiments with and without SEVIRI have been performed in March 2012. The 84 hour forecasts 4 times per day at 00, 06, 12, and 18 UTC, which is verified against the global analysis,will be evaluated and discussed. Applications to Lake Victoria storm case studies and a discussion of ongoing and future work of assimilation cloudy SEVIRI data will be presented.