Geostationary Interferometric Infrared Sounder (GIIRS)

Description

An infrared hyper-spectral vertical sounder, also the first space-borne interferometer that flies in geostationary orbit to take measurements of three dimensional atmospheric structure from interference of split light beams. Technically featured by a sensor array plane, a Michelson interferometer working over different infrared bands for large-area, continuous, fast, and accurate vertical air soundings of temperature and humidity.

Satellite FY-4A  FY-4B 
Weight 315kg
Dimension 1353.5mm (length) × 2179.9mm (width) × 1549mm (height)
Bands Long-wave: 700∼1130cm-1
Mid-wave: 1650∼2250cm-1
Visible: 0.55∼0.90μm
Long-wave: 680∼1130cm-1
Mid-wave: 1650∼2250cm-1
Visible: 0.55∼0.90μm
Spectral resolution Long-wave: 0.8cm-1
Mid-wave: 1.6cm-1
0.8cm-1
Spatial resolution Infrared: 16km SSP
Visible: 2km SSP
Infrared: 12km SSP
Visible: 1km SSP
Temporal resolution 60 min 45 min
Radiation calibration accuracy 1.5K 0.7K
Spectral calibration accuracy 10ppm better than 10ppm

Characteristics

Band Range Sensitivity Calibration accuracy
LWIR 680 ~ 1130 cm-1 0.5 ~ 1.1 mW/(m2sr cm-2) 1 K
MWIR 1650 ~ 2250 cm-1 0.1 ~ 0.14 mW/(m2sr cm-2) 1 K

VIS band

○ SNR: S/N ≥ 200 (ρ=100%)

○ Calibration accuracy: 10 ppm

IR bands:

Band Range Sensitivity Calibration accuracy
LWIR 680 ~ 1130 cm-1 0.5 mW/(m2sr cm-2) 0.7 K
MWIR 1650 ~ 2250 cm-1 0.1 mW/(m2sr cm-2) 0.7 K

VIS band:

○ SNR: S/N ≥ 200 (ρ=100%)

○ Calibration accuracy: better than 10 ppm

Scan range of FY-4A GIIRS (104.7°E)

Scan range of FY-4B GIIRS (133°E)

Data and Products

Satellite Instrument Datasets
FY-4B GIIRS L1 dataL2L3 product
FY-4A GIIRS L1 dataL2L3 product

Calibration and Validation

GIIRS calibration and validation

GIIRS

GIIRS