Introducing the operational GOES imager Clear-Sky Brightness Temperature (CSBT) data products

A new satellite-derived product, called the Clear-Sky Brightness Temperature (CSBT), based on Geostationary Operational Environmental Satellite (GOES) Imager radiance data, was requested by the National Centers for Environmental Prediction (NCEP) Environmental Modeling Center (EMC) and the European Centre for Medium-range Weather Forecasts (ECMWF) for assimilation into global weather prediction models.

The NOAA National Environmental Satellite, Data, and Information Service (NESDIS)/Office of Research and Application (ORA), together with the Cooperative Institute for Meteorological Satellite Studies (CIMSS), have developed software to select cloud-free Fields-Of-View (FOVs), average these data to 50 km areas, and stage the information to Binary Universal FoRm (BUFR) files. This product provides clear sky information for the five spectral bands from both the GOES-East and –West Imagers. Since early November 2001, CIMSS has produced hourly, hemispheric coverage of these data. EMC and ECMWF have successfully accessed and decoded the CSBT data and routinely brought them into their databases. After tests that showed positive impact, ECMWF has been operationally using these data from the water vapor channel (band 3, 6.5/6.7 um) since 7 Oct 2003 for GOES-12 (East), -10 (West), and –9 (western Pacific). EMC has taken an initial look at the data. The NOAA NESDIS/ Office of Satellite Data Processing and Distribution (OSDPD) has incorporated the CSBT processing system.

Assimilation of geostationary satellite data allows a more complete description of the atmosphere for initialization of numerical weather models. The current GOES Imagers provide information on upper tropospheric humidity structures (water vapor channel), the surface temperature, and near surface humidity (window channels). Compared to polar orbiting satellites, the potential impact of geostationary imagers lies especially in the high temporal frequency of radiance observations and increased areal coverage that are available every hour.

Coverage for the GOES East and West CSBT product extends from roughly 67S to 67N and 30W to 165E. For each 50 km processing box the average brightness temperature for each infrared (IR) band is calculated along with the average clear and cloudy brightness temperatures. Processing is performed using the Man computer Interactive Data Access System (McIDAS) and the output information is then transferred from a McIDAS Meteorological Data (MD) file into a BUFR file. Data are available via anonymous file transfer protocol (ftp).