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Microwave Limb Sounder


The Microwave Limb Sounder (MLS) experiments measure naturally-occurring microwave thermal emission from the limb (edge) of Earth's atmosphere to remotely sense vertical profiles of atmospheric gases, temperature, pressure, and cloud ice. The overall objective of these experiments is to provide information that will help improve our understanding of Earth's atmosphere and global change.


Start Date
End Date
N2O GPH Temperature HNO3 All


Current GMT day:    
Maps @ 46hPa; SO2 @ 147hPa and CO @ 215hPa

Latest Publications

  1. Ryan, N., D. Kinnison, R. Garcia, C. Hoffmann, M. Palm, U. Raffalski, and J. Notholt, "Assessing the ability to derive rates of polar middle-atmospheric descent using trace gas measurements from remote sensors," Atmos. Chem. Phys. 18, 3, 1457-1474, doi:10.5194/acp-18-1457-2018, 2018.   reprint  

  2. Raj, S.A., M.V. Ratnam, D.N. Rao, and B.K. Murthy, "Long-term trends in stratospheric ozone, temperature, and water vapor over the Indian region," Annales Geophysicae 36, 1, 149-165, doi:10.5194/angeo-36-149-2018, 2018.   reprint  

  3. Pumphrey, H., N. Glatthor, P. Bernath, C. Boone, J. Hannigan, I. Ortega, N. Livesey, and W. Read, "MLS measurements of stratospheric hydrogen cyanide during the 2015–2016 El Niño event," Atmos. Chem. Phys. 18, 2, 691-703, doi:10.5194/acp-18-691-2018, 2018.   reprint  

  4. Xie, F., X. Zhou, J. Li, Q. Chen, J. Zhang, Y. Li, R. Ding, J. Xue, and X. Ma, "Effect of the Indo-Pacific Warm Pool on Lower-Stratospheric Water Vapor and Comparison with the Effect of ENSO," J. Climate 31, 3, 929-943, doi:10.1175/jcli-d-17-0575.1, 2018.   reprint  

  5. Albers, J., J. Perlwitz, A. Butler, T. Birner, G. Kiladis, Z. Lawrence, G. Manney, A. Langford, and J. Dias, "Mechanisms Governing Interannual Variability of Stratosphere-to-Troposphere Ozone Transport," Journal of Geophysical Research: Atmospheres, doi:10.1002/2017jd026890, 2018.   reprint  

> More Publications

Update to Level 2 v4 Data Quality Document

The Aura Microwave Limb Sounder (MLS) team has updated the "Version 4.2x Level 2 data quality and description document" with revised data screening rules for the water vapor (H2O) and nitrous oxide (N2O) products. This change improves upon the previously recommended screening approach, which inappropriately flagged a large number of H2O and N2O observations in recent years of the mission as unsuitable for scientific use. This unwarranted flagging was a consequence of a slow drift in the performance of the MLS 190 GHz receiver system making these measurements. This instrumental drift, and the related changes in the H2O and N2O products themselves (variations around 0.2-0.8%/year), is discussed further in the document. The MLS team is investigating this drift, and is working towards updated (v5) MLS algorithms that take steps to further alleviate its impacts. This latest version of the document is labeled "v4.2x-3.1" and is available here.

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