# FY-4B Advanced Geostationary Radiation Imager
*sensor . products*

Fifteen-channel FY-4B geostationary VIS/NIR/SWIR/MWIR/TIR imager used for multi-purpose meteorological imagery, cloud and water-vapour tracking, SST, precipitation, and fire monitoring.

## Specifications
- **product status**: operational
- **deployment context**: orbital
- **manufacturer**: cma
- **sensor**: {"instrument_family":"passive-optical","measurement_principle":"passive","spectral_range_nm":{"min":450,"max":12500},"spectral_band_count":15,"gsd_m":{"native":500},"channels":[{"name":"VIS/NIR/SWIR","spectral_range_nm":{"min":450,"max":2300},"spectral_band_count":6,"gsd_m":{"native":500}},{"name":"MWIR/TIR","spectral_range_nm":{"min":3500,"max":12500},"spectral_band_count":9,"gsd_m":{"native":4000}}]}
- **entity type**: sensor
- **last verified date**: 2026-06-16
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: cma
- **attributes**: {"kind":"sensor","product_status":"operational","deployment_context":"orbital","manufacturer":"cma","description":"Fifteen-channel FY-4B geostationary VIS/NIR/SWIR/MWIR/TIR imager used for multi-purpose meteorological imagery, cloud and water-vapour tracking, SST, precipitation, and fire monitoring.","sensor":"{\"instrument_family\":\"passive-optical\",\"measurement_principle\":\"passive\",\"spectral_range_nm\":{\"min\":450,\"max\":12500},\"spectral_band_count\":15,\"gsd_m\":{\"native\":500},\"channels\":[{\"name\":\"VIS/NIR/SWIR\",\"spectral_range_nm\":{\"min\":450,\"max\":2300},\"spectral_band_count\":6,\"gsd_m\":{\"native\":500}},{\"name\":\"MWIR/TIR\",\"spectral_range_nm\":{\"min\":3500,\"max\":12500},\"spectral_band_count\":9,\"gsd_m\":{\"native\":4000}}]}"}
- **technology**: optical-spectral-sensing
- **relevance**: in-scope

## Editorial
## Overview

The FY-4B Advanced Geostationary Radiation Imager (AGRI) is a 15-channel passive optical imager operating from geostationary orbit aboard the FY-4B satellite, launched 2021-06-02.[^nsmc-fy4b] It covers the visible, near-infrared, shortwave infrared, mid-wave infrared, and thermal infrared spectrum from 450 nm to 12,500 nm,[^wmo-agri] supporting meteorological observation, cloud and water-vapour tracking, sea surface temperature retrieval, precipitation estimation, and fire monitoring.

## Spectral design

AGRI carries two focal-plane groups. Six VIS/NIR/SWIR channels span 450-2,300 nm at 500 m to 2 km ground sampling distance (GSD), and nine MWIR/TIR channels span 3,500-12,500 nm at 4 km GSD.[^wmo-agri] The full 15-channel layout, as documented in the SSEC Polar2Grid reader and WMO OSCAR records, is:[^ssec-polar2grid][^wmo-agri]

| Channel | Centre wavelength | GSD |
|---|---|---|
| C01 | 0.47 µm | 1 km |
| C02 | 0.65 µm | 0.5 km |
| C03 | 0.825 µm | 1 km |
| C04 | 1.379 µm | 2 km |
| C05 | 1.61 µm | 2 km |
| C06 | 2.25 µm | 2 km |
| C07 | 3.75 µm (high gain) | 2 km |
| C08 | 3.75 µm (low gain) | 4 km |
| C09 | 6.25 µm | 4 km |
| C10 | 6.95 µm | 4 km |
| C11 | 7.42 µm | 4 km |
| C12 | 8.5 µm | 4 km |
| C13 | 10.8 µm | 4 km |
| C14 | 12.0 µm | 4 km |
| C15 | 13.5 µm | 4 km |

Channel 11 at 7.42 µm (low-level water vapour) is new to FY-4B.[^wmo-agri] The 1.379 µm channel (C04) targets NIR cirrus cloud detection; channels C07 and C08 provide dual split-gain coverage at 3.75 µm.[^ssec-polar2grid] The instrument operates on a 3-axis stabilised geostationary platform with east-west continuous scanning and south-north stepping, enabling full-disk imagery every 15 minutes with shorter-interval regional scans over China.[^nsmc-fy4b]

## Observation applications

Atmospheric motion vectors derived from consecutive AGRI imagery have been demonstrated on FY-4B.[^wmo-agri] Sea surface temperature retrieval using AGRI thermal channels has been demonstrated on FY-4B.[^wmo-agri] Satellite precipitation retrieval has been demonstrated using AGRI data from FY-4B.[^ncbi-agri-aerosol] Thermal anomaly detection for active fire and hotspot identification has been demonstrated on FY-4B.[^wmo-agri] Land surface temperature and emissivity retrieval has been demonstrated on FY-4B.[^ncbi-agri-aerosol] Burned area mapping is demonstrated using AGRI multi-spectral data.[^frontiers-agri-comparison]

Water vapour assimilation studies using FY-4B AGRI radiances in channels C09-C11 have demonstrated positive impact on numerical weather prediction.[^mdpi-fy4b-wv]

## Heritage

AGRI descends from the S-VISSR instruments flown on the FY-2 series (FY-2A through FY-2H), which provided 5-channel imaging. AGRI expanded to 14 channels on FY-4A (2016) and to 15 channels on FY-4B (2021).[^frontiers-agri-comparison]

## Compositional position
- fy-4b (missions) --[mission_payloads]--> FY-4B Advanced Geostationary Radiation Imager

## Sources
- [wmo-agri] | WMO OSCAR instrument record: Advanced Geostationary Radiation Imager | https://space.oscar.wmo.int/instruments/view/agri | tier=agency-doc | accessed=2026-06-16
- [nsmc-fy4b] | NSMC FY-4B satellite page | https://www.nsmc.org.cn/nsmc/en/satellite/FY4B.html | tier=agency-doc | accessed=2026-06-16
- [ssec-polar2grid] | SSEC Polar2Grid FY-4B AGRI L1 reader documentation (channel listing) | https://www.ssec.wisc.edu/software/polar2grid/dev_guide/api/polar2grid.readers.agri_fy4b_l1.html | tier=community | accessed=2026-06-16
- [frontiers-agri-comparison] | General Comparison of FY-4A/AGRI With Other GEO/LEO Instruments (Frontiers Earth Sci., 2018) | https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2018.00224/full | tier=peer-reviewed | accessed=2026-06-16 | published=2018-01-01
- [ncbi-agri-aerosol] | Quality Assessment of AGRI Aerosol Product from FY-4B (Remote Sensing 2024) | https://pmc.ncbi.nlm.nih.gov/articles/PMC11360662/ | tier=peer-reviewed | accessed=2026-06-16 | published=2024-01-01
- [mdpi-fy4b-wv] | Added Value of Assimilating FY-4B AGRI Water Vapor Radiances (Remote Sensing 2025) | https://www.mdpi.com/2072-4292/17/23/3808 | tier=peer-reviewed | accessed=2026-06-16 | published=2025-01-01

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