To increase the observation quality of the Geostationary Interferometric Infrared Sounder (GIIRS) onboard Fengyun-4A (FY-4A) satellite further, the related calibration algorithms of the Level-1 (L1) data of FY-4A/GIIRS have been significantly updated. The new version L1 data (V3) is scheduled to be broadcast since 12:00 November 7, 2019 (BJT), where the main improvements include:

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

2. The GIIRS L1 data is temporarily unapodised;

3. The version name of the L1 data file is changed from V2 to V3.

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

National Satellite Meteorological Center

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