The AIRS Project Instrument Suite measures wavelengths from visible into the microwave. The regions were chosen to sample water at various altitudes, as well as emission wavelengths of other gasses that allow sounding, such as CO2 and O2.

Spectral ranges of all of the EOS Aqua instruments

The AIRS Vis/NIR photometer measures low-level clouds in the visible and NIR.

spectral response functions of the four Vis/NIR photometer bands on AIRS

The AIRS spectrometer measures water vapor and trace gasses in the NIR, MWIR, and LWIR. AIRS has 17 detector array modules covering a continuous spectral range for each module. The spectral range for each module is shown in the table below.

​ Module Name Start ν (cm-1) End ν (cm-1)
M-01a 2552 2677
M-02a 2432 2555
M-01b 2309 2434
M-02b 2169 2312
M-04a 1540 1614
​ M-04b 1460 1527
M-03 1337 1443
M-04c 1283 1339
​ M-04d 1216 1273
M-05 1055 1136
M-06 973 1046
​ M-07 910 974
M-08 851 904
M-09 788 852
M-10 727 782
M-11 687 729
M-12 649 682
spectral coverage of AIRS, showing major spectral features
spectral coverage of AIRS, showing major spectral features


Channels 1-2: surface and moisture

Channels 3-14: oxygen absorption band, providing the primary temperature sounding

Channel 15: surface and moisture (total precipitable water and cloud liquid water)


(AMSU-B channel numbers):

Channel 17: 150 GHz deeper penetration through the atmosphere to the Earth's surface

Channels 18-20: span the strongly opaque water vapor absorption line at 183 GHz and provide data on the atmosphere's humidity level

spectral features and windows in the microwave relevant to the AIRS Project Instrument Suite