References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-11-955-2011

Hydroxyl in the stratosphere and mesosphere – Part 1: Diurnal variability

Minschwaner

¹ Manney

G. L.

¹ ² Wang

S. H.

² Harwood

R. S.

Department of Physics, New Mexico Institute of Mining and Technology, Socorro, USA

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA

University of Edinburgh, Edinburgh, UK

02 02 2011

11 3 955 962

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Diurnal variations in hydroxyl (OH) in the stratosphere and mesosphere are analyzed using measurements from the Aura Microwave Limb Sounder (MLS). The primary driver for OH diurnal variations is the ultraviolet actinic flux that initiates the photochemical production of reactive hydrogen species. The magnitude of this flux is governed largely by changes in solar zenith angle (SZA) throughout the day, and OH diurnal variations are well approximated by an exponential function of the secant of SZA. Measured OH concentrations are fit to a function of the form exp[−βsec(SZA)], where the parameter β is a function of altitude. We examine the magnitude of β and show that it is related to the optical depths of ultraviolet absorption by ozone and molecular oxygen. Values of β from SLIMCAT model simulations show the same vertical structure as those from MLS and the average level of agreement between model and measurements is 6%. The vertical profile of β from MLS can be represented by a simple analytic formulation involving the ozone and water vapor photodissociation rates. This formulation is used to infer the altitude dependence of the primary production mechanisms for OH: the reaction of excited-state atomic oxygen with water vapor versus the direct photodissociation of water vapor.

References 1

Allen, M., Lunine, J. I., and Yung, T. L.: The vertical distribution of ozone in the mesosphere and lower thermosphere, J. Geophys. Res., 89, 4841–4872, 1984.

Anderson, G. P., Clough, S. A., Kneizys, F. X., Chetwynd, J. H., and Shettle, E. P.: AFGL atmospheric constituent profiles (0-120km), AFGL Tech. Rep., AFGL-TR-86-0110, 43~pp., Air Force Phillips Lab., Hanscom AFB, Mass., 1986.

Brasseur, G. and Solomon, S.: Aeronomy of the Middle Atmosphere (3rd ed.), Springer, Dordrecht, 2005.

Burnett, C. R., Minschwaner, K., and Burnett, E. B.: Vertical column abundance measurements of atmospheric hydroxyl from 26°, 40° and 65° N, J. Geophys. Res., 93, 5241–5253, 1989.

Canty, T. and Minschwaner, K.: Seasonal and solar cycle variability of OH in the middle atmosphere, J. Geophys. Res., 107, 4737, doi:10.1029/2002JD002278, 2002.

Canty, T., Pickett, H. M., Salawitch, R. J., Jucks, K. W., Traub, W. A., and Waters, J. W.: Stratospheric and mesospheric HOx: Results from Aura MLS and FIRS-2, Geophys. Res. Lett., 33, L12802, doi:10.1029/2006GL025964, 2006.

Chipperfield, M. P.: Multiannual simulations with a three dimensional chemical transport model, J. Geophys. Res., 104, 1781–1805, 1999.

Chipperfield, M. P.: New version of the TOMCAT/SLIMCAT offline chemical transport model: Intercomparison of stratospheric tracer experiments, Q. J. R. Meteorol. Soc., 132, 1179–1203, 2006.

Dvortsov, V. L. and Solomon, S.: Response of the stratospheric temperatures and ozone to past and future increases in stratospheric humidity, J. Geophys. Res., 106, 7505–7514, 2001.

Englert, C. R., Stevens, M. H., Siskind, D. E., Harlander, J. M., Roesler, F. L., Pickett, H. M., von Savigny, C., and Kochenash, A. J.: First results from the Spatial Heterodyne Imager for Mesospheric Radicals (SHIMMER): Diurnal variation of mesospheric hydroxyl, Geophys. Res. Lett., 35, L19813, doi:10.1029/2008GL035420, 2008.

Gattinger, R. I., Degenstein, D. A., and Llewellyn, E. J.: Optical spectrograph and infra-Red Imaging System (OSIRIS) observations of mesospheric OH A$^2§igma ^+ - X^2\Pi $ 0-0 and 1-1 band resonance emissions, J. Geophys. Res., 111, D13303, doi:10.1029/2005JD006369, 2006.

Hanisco, T. F., Lanzendorf, E. J., Wennberg, P. O., Perkins, K. K., Stimpfle, R. M., Voss, P. B., Anderson, J. G., Cohen, R. C., Fahey, D. W., Gao, R. S., Hintsa, E. J., Salawitch, R. J., Margitan, J. J., McElroy, C. T., and Midwinter, C.: Sources, sinks, and the distribution of OH in the lower stratosphere, J. Phys. Chem. A, 105, 1543–1553, 2001.

Lewis, B. R., Vardavas, I. M., and Carver, J. H.: The aeronomic dissociation of water vapor by solar H Lyman a radiation, J. Geophys. Res., 88, 4935–4940, 1983.

Li, K-F., Cageao, R. P., Karpilovsky, E. P., Mills, F. P., Yung, Y. L., Margolis, J. S., and Sander, S. P.: OH column abundance over Table Mountain Facility, California: AM-PM diurnal asymmetry, Geophys. Res. Lett., 32, L13813, doi:10.1029/2005GL022521, 2005.

McElroy, M. B. and Salawitch, R. J.: Changing composition of the global stratosphere, Science, 243, 763–770, 1989.

Meier, R. R. and D. E. Anderson, Radiation field in the troposphere and stratosphere from 240–1000 nm - I: General analysis, Planet. Space Sci., 30, 923–933, 1982.

Mills, F. P., Cageao, R. P., Sander, S. P., Allen, M., Yung, Y. L., Remsberg, E. E., Russell, J. M., and Richter, U.: OH column abundance over Table Mountain Facility, California: Intra-annual variations and comparisons to model predictions for 1997–2001, J. Geophys. Res., 108(D24), 4785, doi:10.1029/2003JD003481, 2003.

Minschwaner, K., Salawitch, R. J., and McElroy, M. B.: Absorption of solar radiation by O2: implications for O3 and lifetimes of N2O, CFCl3, and CF2Cl2, J. Geophys. Res., 98, 10543–10561, 1993.

Nicolet, M.: On the photodissociation of water vapour in the mesosphere, Planet. Space Sci., 32, 871–880, 1984.

Pickett, H. M., Drouin, B. J., Canty, T., Salawitch, R. J., Fuller, R. A., Perun, V. S., Livesey, N. J., Waters, J. W., Stachnik, R. A., Sander, S. P., Traub, W. A., Jucks, K. W., and Minschwaner, K.: Validation of Aura Microwave Limb Sounder OH and HO2 measurements, J. Geophys. Res., 113, D16S30, doi:10.1029/2007JD008775, 2008.

Salawitch, R. J., Wofsy, S. C., Wennberg, P. O., Cohen, R. C., Anderson, J. G., Fahey, D. W., Gao, R. S., Keim, E. R., Woodbridge, E. L., Stimple, R. M., Koplow, J. P., Kohn, D. W., Webster, C. R., May, R. D., Pfister, L., Gottlieb, E. W., Michelson, H. A., Yue, G. K., Prather, M. J., WIlson, J. C., Brock, C. A., Jonsson, H. H., Dye, J. E., Baumgardner, D., Proffitt, M. H., Loewenstein, M., Podolske, J. R., Elkins, J. W., Dutton, G. S., Hintsa, E. J., Dessler, A. E., Weinstock, E. M., Kelly, K. K., Boering, K. A., Daube, B. C., Chan, K. R., and Bowen, S. W.: The diurnal variation of hydrogen, nitrogen, and chlorine radicals: implications for the heterogeneous production of HNO2, Geophys. Res. Lett., 21, 2551–2554, 1994.

Siskind, D. E., Minschwaner, K., and Eckman, R. S.: Photodissociation of O2 and H2O in the middle atmosphere: comparison of numerical methods and impact on model O3 and OH, Geophys. Res. Lett., 21, 863–866 1994.

Wang, S. H., Pickett, H. M., Pongetti, T. J., Cheung, R., Yung, Y. L., Shim, C., Li, Q. B., Canty, T., Salawitch, R. J., Jucks, K. W., Drouin, B., and Sander, S. P.: Validation of Aura Microwave Limb Sounder OH measurements with Fourier transform ultraviolet spectrometer total OH column measurements at Table Mountain, California, J. Geophys. Res., 113, D22301, doi:10.1029/2008JD009883, 2008.

Waters, J. W., Froidevaux, L., Harwood, R. S., Jarnot, R. F., Pickett, H. M., Read, W. G., Siegel, P. H., Cofield, R. E., Filipiak, M. J., Flower, D. A., Holden, J. R., Lau, G. K. K., Livesey, N. J., Manney, G. L., Pumphrey, H. C., Santee, M. L., Wu, D. L., Cuddy, D. T., Lay, R. R., Loo, M. S., Perun, V. S., Schwartz, M. J., Stek, P. C., Thurstans, R. P., Boyles, M. A., Chandra, K. M., Chavez, M. C., Chen, G. S., Chudasama, B. V., Dodge, R., Fuller, R. A., Girard, M. A., Jiang, J. H., Jiang, Y. B., Knosp, B. W., LaBelle, R. C., Lam, J. C., Lee, K. A., Miller, D., Oswald, J. E., Patel, N. C., Pukala, D. M., Quintero, O., Scaff, D. M., Van Snyder, W., Tope, M. C., Wagner, P. A., and Walch, M. J.: The Earth Observing System Microwave Limb Sounder (EOS MLS) on the Aura satellite, IEEE T. Geosci. Remote, 44, 1075–1092, 2006.

Wennberg, P. O.: Radicals follow the sun, Nature, 442, 145–146, 2006.

Wennberg, P. O., Cohen, R. C., Stimple, R. M., Koplow, J. P., ANderson, J. G., Salawitch, R. J., Fahey, D. W., Woodbridge, E. L., Keim, E. R., Gao, R. S., Webster, C. R., May, R. D., Toohey, D. W., Avallone, L. M., Proffitt, M. H., Loewenstein, M., Podolske, J. R., Chan, K. R., and Wofsy, S. C.: Removal of stratospheric O3 by radicals: In situ measurements of OH, HO2, NO, NO2, ClO, and BrO, Science, 226, 398–404, 1994.