To increase the observation quality of the Geostationary Interferometric Infrared Sounder (GIIRS) onboard Fengyun-4A (FY-4A) satellite, the related calibration algorithms of the Level-1 (L1) data of FY-4A/GIIRS have been updated completely. The new version L1 data (V2) is scheduled to be broadcast since 12:00 August 13, 2019 (BJT), where the main improvements include:

1. The improved spectral and radiometric calibration algorithms are utilized;

2. The apodisation processing upon GIIRS L1 data with Hamming function is adopted;

3. The version name of the L1 data file is changed from V1 to V2.

In general, the data format of GIIRS L1 data remains unchanged.

                                  National Satellite Meteorological Center

                                Contacts: Qiang Guo( guoqiang@cma.gov.cn)