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The EOS MLS Instrument

Instrument Science


The EOS MLS measures thermal emission from broad spectral bands centered near 118, 190, 240, 640 and 2500 GHz are measured continuously (24 hours per day) by 7 microwave receivers (2 each at 118 and 2500 GHz) using a limb viewing geometry which maximizes signal intensities and vertical resolution. MLS is radiometrically calibrated after each 25 second limb scan. Design lifetime is 5 years of continuous operation.
See larger unfolded sideband or folded sideband picture
EOS MLS Folded Spectral Coverage




EOS MLS modules

Instrument Modules

The EOS MLS instrument contains three modules (see picture on left).

(1) The GHz radiometer module, which includes the 118 through 640 GHz receivers and a scanning offset antenna with 0.8 x 1.6 m primary mirror.

(2) The THz radiometer module which contains the 2500 GHz receivers and the THz telescope and scan mirror, whose scan is synchronized with that of the GHz antenna.

(3) The Spectrometer module which receives signals from the GHz and THz radiometer modules, detects and digitizes them, and passes the digitized signals to the spacecraft for telemetry to the ground.


Where is MLS now?




MLS Radiometers and Data Products

Radiometer Primary Data Products Additional Data Products
118 GHz
190 GHz
  • CH3CN (lower quality than from 640 GHz)
  • ClO (lower quality than from 640 GHz)
  • IWC
  • IWP
  • N2O (lower quality than from 640 GHz)
  • O3 (but not in upper trop)
  • volcanic SO2
240 GHz
640 GHz
2.5 THz
  • O3 (lower quality than from other radiometers)

*For v4 and later, the standard N2O product comes from the 190 GHz. The 640 GHz N2O product is of slightly higher quality than the 190 GHz, but the record ends in June 2013.





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Webmaster: Brian Knosp
JPL Clearance: CL# 97-0564