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 data, L2L3 product |
| FY-3B | IRAS | L1 data, L2L3 product |
| FY-3A | IRAS | L1 data |
Calibration and Validation
IRAS