Assimilation of JMA Himawari-8 AHI Clear-Sky Radiance in Operation and GOES-R ABI Radiance in GSI

Himawari-8 is a Japanese weather satellite, the 8^th Himawari geostationary weather satellites operated by the Japan Meteorological Agency. The scope of this study is to assimilate JMA Himawari-8 AHI clear sky (CSR) radiance product in operation. The scatter plot of cloud fraction and first-guess departure indicate a 80% cut-off in cloud fraction of each 16 x 16 pixel box, discarding points with high cloud contamination when cloud fraction is larger than 80%. Quality control has been applied to remove cloud contamination of AHI CSR data in 4DEnVar NCEP GSI (April, 2017 version). Further quality control has been addressed to filter out large first guess departure (> 2 degree).

The Geostationary Operational Environmental Satellite-R Series (GOES-R) is the next generation of geostationary weather satellites. Imaging Earth’s weather, oceans and environment, the Advanced Baseline Imager (ABI) is the primary instrument on GOES-R satellite. We managed to streamline the ABI radiance data format from the original NetCDF into NCEP BUFR. We then assimilated ABI BUFR into NCEP 4DEn-Var GSI (same GSI version as AHI CSR assimilation). In order to compare to AHI CSR, the assimilation time is synchronized for GOES-R ABI. We applied similar cloud filtering algorithm as SEVIRI and adapted from AHI quality control in GSI. Results indicate improved first guess departure and analysis departure. Impact of assimilating AHI CSR and GOES-R ABI on forecast has also been examined in this study.