Aura MLS


Contact: Luis Millan

OH is one of the most chemically-active, and important, molecules in atmospheric chemistry. It is known for its role in controlling middle atmospheric ozone through catalytic reaction cycles that effectively destruct ozone.

OH is mainly produced through photochemistry in the UV region. The primary OH source in the stratosphere is ozone photolysis followed by the reaction with water vapor.

In the mesosphere, direct water vapor photolysis is a major OH source. Due to its short chemical lifetime, OH is generally not affect by transport. It responds rapidly to changes in solar UV radiation and displays diurnal, seasonal, latitudinal, and solar cycle variabilities.

How it is part of MLS Science Objectives

MLS makes the first global measurements of OH during both day and night, which provides needed new information on middle atmospheric hydrogen chemistry that affects ozone.

Lack of long-term global OH measurements has previously been a major limitation in constraining models of stratospheric chemistry.

MLS OH measurements make it possible to study the global distribution and variability of OH, to provide observational evidence of OH response to solar cycle, to pinpoint the altitudes of the distinct nighttime OH layer, and to directly investigate OH changes and impacts during solar energetic particle (SEP) events.

How EOS MLS measures OH

The standard product for OH is taken from the 2.5 THz retrieval. OH has been validated using the balloon-borne FIRS-2 and BOH instruments (for vertical profile shape) [Pickett et al., 2006 , 2008 ] and the ground-based FTUVS instrument (for long-term column variability) [ Wang et al., 2008 ].

The continuous MLS OH data cover from Aug 2004 to Dec 2009. Due to its aging process, the THz sub-instrument of MLS has been in standby mode most of the time after Dec 2009. OH measurements have been limited to one 30-day measurement each year since 2011.

Retrieved concentrations of OH in the mesosphere are sometimes negative with estimated precisions that are much smaller than the size of the negative excursion. These negative concentrations are likely due to subtle inadequacies in the forward model or due to non-linearities in the retrieval.

Positive concentrations in levels adjacent to negative concentrations are likely to overestimate the actual OH concentration, which often lead to a "zig-zag" feature in mesospheric OH vertical profiles.

OH Information from the Spectroscopy Database

Quick Product Information for data version v5

  • Swath Name: OH
  • Status Flag: Only use profiles for which the Status field is an even number.
  • Useful Range: 32-0.0032 hPa
  • DAAC Short Name: ML2OH
  • Precision: Only use values for which the estimated precision is a positive number.
  • Quality Threshold: MLS v5.0x OH data can be used irrespective of the value of the Quality field.
  • Convergence Threshold: <1.1

Download Aura MLS OH v5 data

Latest Publications (OH)

  1. Pumphrey, H., M. Schwartz, M. Santee, G. Kablick III, M. Fromm and N. Livesey
    Microwave Limb Sounder MLS observations of biomass burning products in the stratosphere from Canadian forest fires in August 2017
    Atmos. Chem. Phys. doi:10.5194/acp-21-16645-2021, 2021
  2. Winkler, H., T. Yamada, Y. Kasai, U. Berger and J. Notholt
    Model simulations of chemical effects of sprites in relation with observed HO2 enhancements over sprite-producing thunderstorms
    Atmos. Chem. Phys. doi:10.5194/acp-21-7579-2021, 2021
  3. Winkler, H., T. Yamada, Y. Kasai, U. Berger and J. Notholt
    Model simulations of chemical effects of sprites in relation withsatellite observations
    Atmos. Chem. Phys. doi.10.5194/acp-21-7579-2021, 2021
  4. Häkkilä, T., P. Verronen, L. Millán, M. Szeląg, N. Kalakoski and A. Kero
    Odd hydrogen response thresholds for indication of solar proton and electron impact in the mesosphere and stratosphere
    Annales Geophysicae 10.5194/angeo-38-1299-2020, 2020
  5. Schwartz, M., M. Santee, H. Pumphrey, G. Manney, A. Lambert, N. Livesey, L. Millán, J. Neu, W. Read and F. Werner
    Australian New Year's PyroCb Impact on Stratospheric Composition
    Geophys. Res. Lett. doi:10.1029/2020gl090831, 2020
  6. Arsenovic, P., A. Damiani, E. Rozanov, B. Funke, A. Stenke and T. Peter
    Reactive nitrogen NOy and ozone responses to energetic electron precipitation during Southern Hemisphere winter
    Atmos. Chem. Phys. doi:10.5194/acp-19-9485-2019, 2019
  7. Zawedde, A., H.N. Tyssøy, J. Stadsnes and M. Sandanger
    Are EEP Events Important for the Tertiary Ozone Maximum?
    Journal of Geophysical Research: Space Physics doi:10.1029/2018ja026201, 2019
  8. Kulikov, M., A. Nechaev, M. Belikovich, T. Ermakova and A. Feigin
    Technical note: Evaluation of the simultaneous measurements of mesospheric OH, HO2, and O3 under a photochemical equilibrium assumption - a statistical approach
    Atmos. Chem. Phys. doi:10.5194/acp-18-7453-2018, 2018
  9. Zawedde, A., H.N. Tyssøy, J. Stadsnes and M. Sandanger
    The Impact of Energetic Particle Precipitation on Mesospheric OH - Variability of the Sources and the Background Atmosphere
    Journal of Geophysical Research: Space Physics doi:10.1029/2017ja025038, 2018
  10. Hegglin, M., S. Tegtmeier, J. Anderson, A. Bourassa, S. Brohede, D. Degenstein, L. Froidevaux, B. Funke, J. Gille, A. Jones, Y. Kasai, E. Kyrola, J. Lumpe, J. Neu, E. Remsberg, A. Rozanov, M. Toohey, J. Urban, T. von Clarmann, K.A. Walker and R. Wang
    The SPARC Data Initiative: Assessment of stratospheric trace gas and aerosol climatologies from satellite limb sounders
  11. Li, K., Q. Zhang, S. Wang, S. Sander and Y. Yung
    Resolving the Model-Observation Discrepancy in the Mesospheric and Stratospheric HOx Chemistry
    Earth and Space Science doi:10.1002/2017ea000283, 2017
  12. Santee, M.L., G.L. Manney, N.J. Livesey, M.J. Schwartz, J.L. Neu and W.G. Read
    A comprehensive overview of the climatological composition of the Asian summer monsoon anticyclone based on 10 years of Aura Microwave Limb Sounder measurements
    Journal of Geophysical Research: Atmospheres doi:10.1002/2016jd026408, 2017
  13. Andersson, M.E., P.T. Verronen, D.R. Marsh, S.M. Paivarinta and J.M.C. Plane
    WACCM-D-Improved modeling of nitric acid and active chlorine during energetic particle precipitation
    Journal of Geophysical Research: Atmospheres doi:10.1002/2015jd024173, 2016
  14. Verkhoglyadova, O.P., J.M. Wissing, S. Wang, M.B. Kallenrode and G.P. Zank
    Nighttime mesospheric hydroxyl enhancements during SEP events and accompanying geomagnetic storms: Ionization rate modeling and Aura satellite observations
    Journal of Geophysical Research: Space Physics doi:10.1002/2015ja022217, 2016
  15. Zawedde, A., H.N. Tyssøy, R. Hibbins, P. Espy, L. Ødegaard, M. Sandanger and J. Stadsnes
    The impact of energetic electron precipitation on mesospheric hydroxyl during a year of solar minimum
    Journal of Geophysical Research: Space Physics doi:10.1002/2016ja022371, 2016
  16. Fytterer, T., M.L. Santee, M. Sinnhuber and S. Wang
    The 27 day solar rotational effect on mesospheric nighttime OH and O3 observations induced by geomagnetic activity
    Journal of Geophysical Research: Space Physics doi:10.1002/2015ja021183, 2015
  17. Sonkaew, T. and R. Macatangay
    Determining relationships and mechanisms between tropospheric ozone column concentrations and tropical biomass burning in Thailand and its surrounding regions
    Environmental Research Letters doi:10.1088/1748-9326/10/6/065009, 2015
  18. Andersson, M.E., P.T. Verronen, C.J. Rodger, M.A. Clilverd and S. Wang
    Longitudinal hotspots in the mesospheric OH variations due to energetic electron precipitation.
    Atmos. Chem. Phys. doi:10.5194/acp-14-1095-2014, 2014
  19. Hassler, B., I. Petropavlovskikh, J. Staehelin, T. August, P.K. Bhartia, C. Clerbaux, D. Degenstein, M.D. Mazière, B.M. Dinelli, A. Dudhia, G. Dufour, S.M. Frith, L. Froidevaux, S. Godin-Beekmann, J. Granville, N.R.P. Harris, K. Hoppel, D. Hubert, Y. Kasai, M.J. Kurylo, E. Kyrölä, J.C. Lambert, P.F. Levelt, C.T. McElroy, R.D. McPeters, R. Munro, H. Nakajima, A. Parrish, P. Raspollini, E.E. Remsberg, K.H. Rosenlof, A. Rozanov, T. Sano, Y. Sasano, M. Shiotani, H.G.J. Smit, G. Stiller, J. Tamminen, D.W. Tarasick, J. Urban, R.J.d. van A, J.P. Veefkind, C. Vigouroux, T. von Clarmann, C. von Savigny, K.A. Walker, M. Weber, J. Wild and J.M. Zawodny
    Past changes in the vertical distribution of ozone - Part 1: Measurement techniques, uncertainties and availability
    Atmospheric Measurement Techniques doi:10.5194/amt-7-1395-2014, 2014
  20. Verkhoglyadova, O.P., S. Wang, M.G. Mlynczak, L.A. Hunt and G.P. Zank
    Effects of two large solar energetic particle events on middle atmosphere nighttime odd hydrogen and ozone content: Aura/MLS and TIMED/SABER measurements
    J. Geophys. Res. - Space doi:10.1002/2014JA020609, 2014
  21. Verkhoglyadova, O.P. and S. Wang
    Middle Atmosphere Response to Large SEP Events: September 2005 Event
    Outstanding Problems in Heliophysics: From Coronal Heating to the Edge of the Heliosphere 2014
  22. Medvedeva, I., A. Semenov, V. Perminov, A. Beletsky and A. Tatarnikov
    Comparison of ground-based OH temperature data measured at Irkutsk 52°N, 103°E and Zvenigorod 56°N, 37°E stations with Aura MLS v3.3
    Acta Geophysica doi:10.2478/s11600-013-0161-x, 2013
  23. Shapiro, A.V., E.V. Rozanov, A.I. Shapiro, T.A. Egorova, J. Harder, M. Weber, A.K. Smith, W. Schmutz and T. Peter
    The role of the solar irradiance variability in the evolution of the middle atmosphere during 2004-2009
    J. Geophys. Res. doi:10.1002/jgrd.50208, 2013
  24. Wang, S., K.F. Li, T.J. Pongetti, S.P. Sander, Y.L. Yung, M.C. Liang, N.J. Livesey, M.L. Santee, J.W. Harder, M. Snow and F.P. Mills
    Midlatitude atmospheric OH response to the most recent 11-y solar cycle
    Proc. Nat. Acad. Sci. doi:10.1073/pnas.1117790110, 2013
  25. Andersson, M.E., P.T. Verronen, S. Wang, C.J. Rodger, M.A. Clilverd and B.R. Carson
    Precipitating radiation belt electrons and enhancements of mesospheric hydroxyl durign 2004-2009
    J. Geophys. Res. doi:10.1029/2011JD017246, 2012
  26. Shapiro, A.V., E. Rozanov, A.I. Shapiro, S. Wang, T. Egorova, W. Schmutz and Th. Peter
    Signature of the 27-day solar rotation cycle in mesospheric OH and H2O observed by the Aura Microwave Limb Sounder
    Atmos. Chem. Phys. doi:10.5194/acp-12-3181-2012, 2012
  27. Jackman, C.H., D.R. Marsh, F.M. Vitt, R.G. Roble, C.E. Randall, P.F. Bernath, B. Funke, M. Lopez-Puertas, S. Versick, G.P. Stiller, A.J. Tylka and E.L. Flemming
    Northern Hemisphere atmospheric influence of the solar proton events and ground level enhancement in January 2005
    Atmos. Chem. Phys. doi:10.5194/acp-11-6153-2011, 2011
  28. Minschwaner, K.R., G.L. Manney, S.H. Wang and R.S. Harwood
    Hydroxyl in the stratosphere and mesosphere - Part 1: Diurnal variability
    Atmos. Chem. Phys. doi:10.5194/acp-11-955-2011, 2011
  29. Sovde, O.A., Y.J. Orsolini, D.R. Jackson, F. Stordal, I.S.A. Isaksen and B. Rognerud
    Estimation of Arctic O3 loss during winter 2006/2007 using data assimilation and comparison with a chemical transport model
    Q. J. Roy. Meteorol. Soc. doi:10.1002/qj.740, 2011
  30. Verronen, P.T., C.J. Rodger, M.A. Clilverd and S.H. Wang
    First evidence of mesospheric hydroxyl response to electron precipitation from the radiation belts
    J. Geophys. Res. doi:10.1029/2010JD014965, 2011
  31. Wu, L., H. Su and J.H. Jiang
    Regional simulations of deep convection and biomass burning over South America: 1. Model evaluations using multiple satellite data sets
    J. Geophys. Res. doi:10.1029/2011JD016105, 2011
  32. Damiani, A., M. Storini, C. Rafanelli and P. Diego
    The hydroxyl radical as an indicator of SEP fluxes in the high-latitude terrestrial atmosphere
    Adv. Space Res. doi:10.1016/j.asr.2010.06.022, 2010
  33. Damiani, A., M. Storini, M.L. Santee and S. Wang
    Variability of the nighttime OH layer and mesospheric ozone at high latitudes during northern winter: influence of meteorology
    Atmos. Chem. Phys. doi:10.5194/acp-10-10291-2010, 2010
  34. Englert, C.R., M.H. Stevens, D.E. Siskind, J.M. Harlander and F.L. Roesler
    Spatial Heterodyne Imager for Meospheric Radicals on STPSat-1
    J. Geophys. Res. doi:10.1029/2010JD014398, 2010
  35. Minschwaner, K., G.L. Manney, N.J. Livesey, H.C. Pumphrey, H.M. Pickett, L. Froidevaux, A. Lambert, M.J. Schwartz, P.F. Bernath, K.A. Walker and C.D. Boone
    The photochemistry of carbon monoxide in the stratosphere and mesosphere evaluated from observations by the Microwave Limb Sounder on the Aura satellite
    J. Geophys. Res. doi:10.1029/2009JD012654, 2010
  36. Wargan, K., S. Pawson, I. Stajner and V. Thouret
    Spatial structure of assimilated ozone in the upper troposphere and lower stratosphere
    J. Geophys. Res. doi:10.1029/2010JD013941, 2010
  37. Damiani, A., M. Storini, M. Laurenza and C. Rafanelli
    Solar particle effects on minor components of the Polar atmosphere
    Annales Geophysicae doi:10.5194/angeo-26-361-2008, 2008
  38. Englert, C.R., M.H. Stevens, D.E. Siskind, J.M. Harlander, F.L. Roesler, H.M. Pickett, C. von Savigny and A.J. Kochenash
    First results from the Spatial Heterodyne Imager for Mesospheric Radicals (SHIMMER): Diurnal variation of mesospheric hydroxyl
    Geophys. Res. Lett. doi:10.1029/2008GL035420, 2008
  39. Pickett, H.M., B.J. Drouin, T. Canty, R.J. Salawitch, R.A. Fuller, V.S. Perun, N.J. Livesey, J.W. Waters, R.A. Stachnik, S.P. Sander, W.A. Traub, K.W. Jucks and K. Minschwaner
    Validation of Aura Microwave Limb Sounder OH and HO2 measurements
    J. Geophys. Res. doi:10.1029/2007JD008775, 2008
  40. Roesevall, J.D., D.P. Murtagh, J. Urban, W. Feng, P. Eriksson and S. Brohede
    A study of ozone depletion in the 2004/2005 Arctic winter based on data from Odin/SMR and Aura/MLS
    J. Geophys. Res. doi:10.1029/2007JD009560, 2008
  41. Wang, S., H.M. Pickett, T.J. Pongetti, R. Cheung, Y.L. Yung, C. Shim, Q. Li, T. Canty, R.J. Salawitch, K.W. Jucks, B. Drouin and S.P. Sander
    Validation of Aura Microwave Limb Sounder OH measurements with Fourier Transform Ultra-Violet Spectrometer total OH column measurements at Table Mountain, California
    J. Geophys. Res. doi:10.1029/2008JD009883, 2008
  42. Hocke, K., N. Kampfer, D. Ruffieux, L. Froidevaux, A. Parrish, I. Boyd, T. von Clarmann, T. Steck, Y.M. Timofeyev, A.V. Polyakov and E. Kyrola
    Comparison and synergy of stratospheric ozone measurements by satellite limb sounders and the ground-based microwave radiometer SOMORA
    Atmos. Chem. Phys. doi:10.5194/acp-7-4117-2007, 2007
  43. Mueller, E.R., R. Henschke, W.E. Robotham Jr., L.A. Newman, L.M. Laughman, R.A. Hart, J. Kennedy and H.M. Pickett
    Terahertz local oscillator for the Microwave Limb Sounder on the Aura Satellite
    Appl. Opt. doi:10.1364/AO.46.004907, 2007
  44. Verronen, P.T., C.J. Rodger, M.A. Clilverd, H.M. Pickett and E. Turunen
    Latitudinal extent of the January 2005 solar proton event in the Northern Hemisphere from satellite observations of hydroxyl
    Annales Geophysicae doi:10.5194/angeo-25-2203-2007, 2007
  45. Canty, T., H.M. Pickett, R.J. Salawitch, K.W. Jucks, W.A. Traub and J.W. Waters
    Stratospheric and Mesospheric HOx: Results from Aura MLS and FIRS-2
    Geophys. Res. Lett. doi:10.1029/2006GL025964, 2006
  46. Pickett, H.M.
    Microwave Limb Sounder THz Module on Aura
    IEEE Trans. Geosci. Remote Sensing doi:10.1109/TGRS.2005.862667, 2006
  47. Pickett, H.M., W.G. Read, K.K. Lee and Y.L. Yung
    Observation of Night OH in the Mesosphere
    Geophys. Res. Lett. doi:10.1029/2006GL026910, 2006
  48. Pickett, H.M., B.J. Drouin, T. Canty, L.J. Kovalenko, R.J. Salawitch, N.J. Livesey, W.G. Read, J.W. Waters, K.W. Jucks and W.A. Traub
    Validation of Aura MLS HOx measurements with remote-sensing balloon instruments
    Geophys. Res. Lett. doi:10.1029/2005GL024048, 2006
  49. Verronen, P.T., A. Seppala, E. Kyrola, J. Tamminen, H.M. Pickett and E. Turunen
    Production of Odd Hydrogen in the Mesosphere During the January 2005 Solar Proton Event
    Geophys. Res. Lett. doi:10.1029/2006GL028115, 2006
  50. Gaidis, M.C., H.M. Pickett, C.D. Smith, S.C. Martin, R.P. Smith and P.H. Siegel
    A 2.5-THz Receiver Front End for Spaceborne Applications
    IEEE Trans. Microwave Theory and Techniques doi:10.1109/THZ.1998.731652, 2000
  51. Pickett, H.M. and D.B. Peterson
    Comparison of measured stratospheric OH with prediction
    J. Geophys. Res. doi:10.1029/96JD01168, 1996