Radiometric Calibration Accuracy of GOES Sounder Infrared Channels

Quality infrared (IR) radiances and their derived products from the Geostationary Environmental Operational Satellite (GOES) Sounder are very important data sources to weather prediction and nowcasting applications for the continental United States and adjacent ocean regions. With demanding requirements for more accurate weather nowcasting models and climate change studies, it is necessary to assess and improve the radiometric calibration accuracy of the GOES Sounder data. The objective of this paper is to examine the GOES Sounder IR radiometric calibration accuracy, and the diurnal calibration variation using intercalibration with two well-calibrated hyperspectral radiometers onboard low earth orbit satellites, the Atmospheric Infrared Sounder (AIRS) on the Aqua satellite and the Infrared Atmospheric Sounding Interferometer (IASI) on the Metop-A satellite. The results show that most sounder IR channels of GOES-11 through GOES-15 are well calibrated outside of the satellite midnight effect time period, with a less than 0.5 K of mean bias of brightness temperature with respect to IASI. Yet, the impact of the satellite midnight effect on the radiance quality varies greatly at different IR channels among different satellites. Further research is needed to understand the changes of instrument environmental flux on the GOES IR radiance around satellite midnight.