Infra-Red Atmospheric Sounder (IRAS)

Description

This is the primary sounder for FY-3A/B/C. It is a High Resolution Infrared Radiation Sounder (HIRS)/3-like instrument. There are a total of 26 channels in this IR sounder. The first 20 channels are almost the same as HIRS/3, while the 6 additional channels shall enable IRAS to measure aerosols, carbon dioxide content, and cirrus. The instrument ground instantaneous field of view (IFOV) is 17 km at nadir.

Infrared spectrometer is an atmospheric sounding instrument, mainly detects the Earth's surface and atmosphere up IR-band emission of radiation, gets inversion from surface to about 40 km to the different level of distribution of atmospheric temperature and humidity.

Infrared spectrometer has a total of 26 spectral channels, provides initial field information for numerical weather prediction models, especially in the mountains, oceans, to the scarcity of desert areas such as meteorological station, which is an irreplaceable role to play.

Using infrared spectrometer, inversion resulting atmospheric temperature and humidity of the vertical distribution of information also reflects the local atmosphere of stability and helps the Meteorological Department and small scale weather systems forecast analysis.

Infrared spectrometer data and microwave thermometer implementation data in conjunction with the temperature and humidity can improve accuracy of cloud, rain, three-dimensional weather process internal temperature and water vapor distribution structure, such as typhoons, storm for severe weather monitoring and provides a strong support in prediction of the process.

Satellite FY-3A FY-3B FY-3C 
No. Channels 26 (6 shortwave IR)
Spatial Resolution 17km
Weight 65kg
Power 80W

Characteristics

Channel Center wave number (cm-1) Central wavelength (μm) Half power bandwidth (cm-1) Main absorbing gases Highest temperature (K) NEΔ(mW/m2•sr•cm-1) Contribution limit (hPa)
1 669 14.95 3 CO2 280 4.00 30
2 680 14.71 10 CO2 265 0.80 60
3 690 14.49 12 CO2 250 0.60 100
4 703 14.22 16 CO2 260 0.35 400
5 716 13.97 16 CO2 275 0.32 600
6 733 13.84 16 CO2/H2O 290 0.36 800
7 749 13.35 16 CO2/H2O 300 0.30 900
8 802 12.47 30 Atmospheric window 330 0.20 Earth's surface
9 900 11.11 35 Atmospheric window 330 0.15 Earth's surface
10 1030 9.71 25 O3 280 0.20 25
11 1345 7.43 50 H2O 330 0.23 800
12 1365 7.33 40 H2O 285 0.30 700
13 1533 6.52 55 H2O 275 0.30 500
14 2188 4.57 23 N2O 310 0.009 1000
15 2210 4.57 23 N2O 290 0.004 950
16 2235 4.47 23 CO2/N2O 280 0.006 700
17 2245 4.45 23 CO2/N2O 266 0.006 400
18 2388 4.19 25 CO2 320 0.003 大气
19 2515 3.98 35 Atmospheric window 340 0.003 Earth's surface
20 2660 3.76 100 Atmospheric window 340 0.002 Earth's surface
21 14500 0.69 1000 Atmospheric window 100%A 0.10%A Cloud
22 11299 0.885 385 Atmospheric window 100%A 0.10%A Earth's surface
23 10638 0.94 550 H2O 100%A 0.10%A Earth's surface
24 10638 0.94 200 H2O 100%A 0.10%A Earth's surface
25 8065 1.24 650 H2O 100%A 0.10%A Earth's surface
26 6098 1.64 450 H2O 100%A 0.10%A Earth's surface

Data and Products

Satellite Instrument Datasets
FY-3C IRAS L1 dataL2L3 product
FY-3B IRAS L1 dataL2L3 product
FY-3A IRAS L1 data

Calibration and Validation

IRAS calibration and validation

FY-3C IRAS SRF (RAR)

FY-3B IRAS SRF (RAR)

FY-3A IRAS SRF (RAR)

IRAS

IRAS