Evaluation of daily average OLR retrieved jointly by FY-3 multiple satellites

Outgoing longwave radiation (OLR) of the atmosphere top (TOA) is an important component of the radiation energy balance of the TOA. The Medium Resolution Imaging Spectrometer (MERSI) carried by the FY-3D and FY-3E satellites can be used for OLR calculation. This paper described the algorithm of MERSI OLR, and the consistency and accuracy of FY-3D MERSI and FY-3E MERSI instantaneous OLR were evaluated based on AQUA CERES OLR. The inspection results showed that the FY-3D and FY-3E MERSI OLR accuracy were basically consistent. And there was uniformly negative deviation compared AQUA CERES instantaneous OLR, the average deviation was about -3 W m^-2, and the RMSE was about 6-7 W m^-2. On this basis, the ability of daily mean OLR retrieved from FY-3D MERSI and FY-3E MERSI was discussed. The results showed that the accuracy of OLR from four-time observation per day was higher than that from two-time observation per day. The average OLR of the four-time observation per day could be better represent the diurnal variation of that, and the diurnal variation characteristics of OLR also was provided with seasonal changes. In general, the OLR retrieval capabilities of FY-3D and FY-3E satellites are equivalent, and the joint use of them is better on daily mean OLR retrieval. This study can provide a basis for users to analyze OLR data of Fengyun satellites.