# FY-4B
*missions*

Second FY-4 geostationary meteorological satellite and first operational unit of the series, carrying AGRI, GIIRS-2, and GHI meteorological payloads.

## Specifications
- **operator**: cma
- **actual launch**: 2021-06-03
- **current status**: operational
- **orbit type**: Geostationary orbit, 105 E, 35786 km; WMO records relocation from 133 E to 105 E in February 2024
- **tasking supported**: false
- **launch vehicle**: casc-long-march-3b
- **entity type**: mission
- **last verified date**: 2026-06-14
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: cma
- **attributes**: {"operator":"cma","actual_launch":"2021-06-03","current_status":"operational","orbit_type":"Geostationary orbit, 105 E, 35786 km; WMO records relocation from 133 E to 105 E in February 2024","tasking_supported":false,"description":"Second FY-4 geostationary meteorological satellite and first operational unit of the series, carrying AGRI, GIIRS-2, and GHI meteorological payloads.","launch_vehicle":"casc-long-march-3b"}
- **relevance**: in-scope

## Editorial
FY-4B (Fengyun-4B) is the second satellite in China's FY-4 third-generation geostationary meteorological series and the first designated as an operational unit of the series, operated by the China Meteorological Administration. The satellite launched in June 2021 and is currently stationed at 105 degrees East following relocation from 133 degrees East in February 2024.[^nsmc-fy4b][^wmo-fy-4b]

The Earth-observation sensor stack includes three instruments. The Advanced Geostationary Radiation Imager (AGRI) provides multi-channel visible and infrared imagery for atmospheric motion vectors, sea surface temperature, precipitation estimates, and thermal anomaly detection.[^wmo-agri] The Geostationary Interferometric Infrared Sounder-2 (GIIRS-2) is an upgraded sounder supporting atmospheric temperature and humidity profiling and tropospheric trace-gas column retrieval.[^wmo-giirs-2] The Geostationary High-speed Imager (GHI) delivers rapid-cadence imaging for sub-minute atmospheric phenomena monitoring.[^wmo-ghi]

Ancillary payloads include a data collection system (DCS) and a space-environment particle monitoring package (SEP). Compared to FY-4A, the FY-4B introduces the GHI rapid-scan imager and an upgraded sounder as its main capability enhancements.[^cma-fy4b-payload-paper]

## Compositional position
- FY-4B --[mission_payloads]--> agri-fy-4b (products)
- FY-4B --[mission_payloads]--> giirs-2 (products)
- FY-4B --[mission_payloads]--> ghi (products)
- FY-4B --[mission_payloads]--> dcs-fy-4b (products)
- FY-4B --[mission_payloads]--> sep-fy-4b (products)
- FY-4B --[related-topic]--> weather-nowcasting (topics)
- FY-4B --[related-topic]--> atmospheric-wind (topics)
- FY-4B --[related-topic]--> atmospheric-profiling (topics)
- FY-4B --[related-topic]--> sea-surface-temperature (topics)
- FY-4B --[related-topic]--> precipitation (topics)
- FY-4B --[related-topic]--> wildfire (topics)
- FY-4B --[related-topic]--> air-quality (topics)

## Sources
- [nsmc-fy4b] | NSMC FY-4B satellite page | https://www.nsmc.org.cn/nsmc/en/satellite/FY4B.html | tier=agency-doc | accessed=2026-06-14
- [wmo-fy-4b] | WMO OSCAR satellite record: FY-4B | https://space.oscar.wmo.int/satellites/view/fy_4b | tier=agency-doc | accessed=2026-06-14
- [ceos-fy-4b] | CEOS MIM FY-4B mission summary | https://database.eohandbook.com/database/missionsummary.aspx?missionID=533 | tier=community | accessed=2026-06-14
- [cma-fy4b-payload-paper] | Introduction of FY-4B instruments and post-launch calibration results | https://www.data.jma.go.jp/mscweb/en/aomsuc12/presentation/S5_09.pdf | tier=agency-doc | accessed=2026-06-14
- [wmo-agri] | WMO OSCAR instrument record: Advanced Geostationary Radiation Imager | https://space.oscar.wmo.int/instruments/view/agri | tier=agency-doc | accessed=2026-06-14
- [wmo-giirs-2] | WMO OSCAR instrument record: Geostationary Interferometric Infrared Sounder-2 | https://space.oscar.wmo.int/instruments/view/giirs_2 | tier=agency-doc | accessed=2026-06-14
- [wmo-ghi] | WMO OSCAR instrument record: Geostationary High-speed Imager | https://space.oscar.wmo.int/instruments/view/ghi | tier=agency-doc | accessed=2026-06-14

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Source: https://eo-atlas.org/missions/fy-4b
Maintainer: SpectraWorks B.V. (CC-BY 4.0)