Global carbon monoxide column derived from the HIRAS-II/FY-3F satellite observations

The Hyperspectral Infrared Atmospheric Sounder-II (HIRAS-II) onboard China’s FungYun (FY)-3F meteorological satellite was launched in August 2023. This study presents the first attempt to retrieve the global carbon monoxide (CO) column from the HIRAS-II/FY-3F spectra based on a newly established full-physical algorithm. The CO global columns derived from the HIRAS-II/FY-3F satellite are compared to the measurements from the Infrared Atmospheric Sounding Interferometer (IASI) onboard Europe's MetopB satellite, as both satellites have the same spectral range with a similar overpass time. The correlation coefficient between the IASI/Metop-B and HIRAS-II/FY-3F CO retrievals is about 0.8. The HIRAS-II/FY-3F satellite can well capture the regions with high CO values, e.g., Africa, North America, and East Asia. The relative difference in the CO global column between HIRAS-II and IASI is 1.2±13.7(1σ)%, which is within their combined retrieval uncertainty. The CO plumes from the fire emission in North America between 18 and 23 July 2024 were observed by the HIRAS-II/FY-3F satellite and consistent with the Copernicus Atmosphere Monitoring Service (CAMS) model simulations. Our results show that the HIRAS-II/FY-3F spectra are of good quality to provide quantitative observations of global CO column remote sensing observations.