# Geostationary Interferometric Infrared Sounder-2
*sensor . products*

FY-4B geostationary MWIR/TIR interferometric infrared sounder for temperature and humidity sounding and wind-profile derivation from water-vapour features.

## Specifications
- **product status**: operational
- **deployment context**: orbital
- **manufacturer**: cma
- **sensor**: {"instrument_family":"passive-optical","measurement_principle":"passive","spectral_range_nm":{"min":550,"max":14700},"gsd_m":{"native":12000},"channels":[{"name":"LWIR","spectral_range_nm":{"min":8850,"max":14700},"gsd_m":{"native":12000}},{"name":"MWIR","spectral_range_nm":{"min":4440,"max":6060},"gsd_m":{"native":12000}},{"name":"VIS cloud-detection channel","spectral_range_nm":{"min":550,"max":900},"gsd_m":{"native":1000}}]}
- **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":"FY-4B geostationary MWIR/TIR interferometric infrared sounder for temperature and humidity sounding and wind-profile derivation from water-vapour features.","sensor":"{\"instrument_family\":\"passive-optical\",\"measurement_principle\":\"passive\",\"spectral_range_nm\":{\"min\":550,\"max\":14700},\"gsd_m\":{\"native\":12000},\"channels\":[{\"name\":\"LWIR\",\"spectral_range_nm\":{\"min\":8850,\"max\":14700},\"gsd_m\":{\"native\":12000}},{\"name\":\"MWIR\",\"spectral_range_nm\":{\"min\":4440,\"max\":6060},\"gsd_m\":{\"native\":12000}},{\"name\":\"VIS cloud-detection channel\",\"spectral_range_nm\":{\"min\":550,\"max\":900},\"gsd_m\":{\"native\":1000}}]}"}
- **relevance**: in-scope

## Editorial
Geostationary Interferometric Infrared Sounder-2 is the FY-4B-class GIIRS sounder: a geostationary nadir MWIR/TIR interferometric infrared payload for temperature and humidity sounding and wind-profile derivation from water-vapour features [^wmo-giirs-2][^nsmc-fy4b]. It is a sounding instrument rather than an imager, with hyperspectral infrared channels for atmospheric profiling and a visible channel for cloud detection [^wmo-giirs-2][^nsmc-giirs]. The FY-4B configuration covers LWIR 680-1130 cm^-1, MWIR 1650-2250 cm^-1, and a 0.55-0.90 um visible channel; in wavelength terms, that is roughly 8.85-14.7 um for LWIR, 4.44-6.06 um for MWIR, and 0.55-0.90 um visible context [^wmo-giirs-2]. Ground sampling is 12 km at sub-satellite point for the infrared sounding channels and 1 km for the visible channel, with a 45 minute China-area cycle in the FY-4B characteristics [^wmo-giirs-2]. The GIIRS-2 label also spans later FY-4 configurations in operational records, while the family characteristics separate FY-4A, FY-4B, and FY-4C values; FY-4C range, SNR, and spatial-resolution improvements remain tied to that later configuration rather than carried back into FY-4B-class GIIRS-2 [^wmo-giirs-2][^nsmc-giirs].

## Compositional position
- fy-4b (missions) --[mission_payloads]--> Geostationary Interferometric Infrared Sounder-2

## Sources
- [wmo-giirs-2] | WMO OSCAR instrument record: GIIRS-2 | https://space.oscar.wmo.int/instruments/view/giirs_2 | tier=agency-doc | accessed=2026-06-16
- [nsmc-giirs] | NSMC GIIRS instrument page | https://www.nsmc.org.cn/nsmc/en/instrument/GIIRS.html | 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

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Source: https://eo-atlas.org/products/sensor/giirs-2
Maintainer: SpectraWorks B.V. (CC-BY 4.0)