Hydroxyl in the stratosphere and mesosphere – Part 1: Diurnal variability
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Published:2011-02-02
Issue:3
Volume:11
Page:955-962
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ISSN:1680-7324
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Container-title:Atmospheric Chemistry and Physics
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language:en
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Short-container-title:Atmos. Chem. Phys.
Author:
Minschwaner K.,Manney G. L.,Wang S. H.,Harwood R. S.
Abstract
Abstract. 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.
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference26 articles.
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. 2. 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. 3. Brasseur, G. and Solomon, S.: Aeronomy of the Middle Atmosphere (3rd ed.), Springer, Dordrecht, 2005. 4. 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. 5. Canty, T. and Minschwaner, K.: Seasonal and solar cycle variability of OH in the middle atmosphere, J. Geophys. Res., 107, 4737, https://doi.org/10.1029/2002JD002278, 2002.
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