Journal of Atmospheric Chemistry

, Volume 71, Issue 1, pp 55–64

OH in the tropical upper troposphere and its relationships to solar radiation and reactive nitrogen

  • R. S. Gao
  • K. H. Rosenlof
  • D. W. Fahey
  • P. O. Wennberg
  • E. J. Hintsa
  • T. F. Hanisco
Article

DOI: 10.1007/s10874-014-9280-2

Cite this article as:
Gao, R.S., Rosenlof, K.H., Fahey, D.W. et al. J Atmos Chem (2014) 71: 55. doi:10.1007/s10874-014-9280-2

Abstract

In situ measurements of [OH], [HO2] (square brackets denote species concentrations), and other chemical species were made in the tropical upper troposphere (TUT). [OH] showed a robust correlation with solar zenith angle. Beyond this dependence, however, [OH] did not correlate to its primary source, the product of [O3] and [H2O] ([O3]•[H2O]), or its sink [NOy]. This suggests that [OH] is heavily buffered in the TUT. One important exception to this result is found in regions with very low [O3], [NO], and [NOy]. Under these conditions, [OH] is highly suppressed, pointing to the critical role of NO in sustaining OH in the TUT and the possibility of low [OH] over the western Pacific warm pool due to strong marine convections bringing NO-poor air to the TUT. In contrast to [OH], [HOx] ([OH] + [HO2]) correlated reasonably well with [O3]•[H2O]/[NOy], suggesting that [O3]•[H2O] and [NOy] are the significant source and sink, respectively, of [HOx].

Keywords

OHIn situTropical upper troposphereSTRAT

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • R. S. Gao
    • 1
  • K. H. Rosenlof
    • 1
  • D. W. Fahey
    • 1
    • 2
  • P. O. Wennberg
    • 3
  • E. J. Hintsa
    • 2
    • 4
  • T. F. Hanisco
    • 5
  1. 1.Chemical Sciences Division, Earth System Research LaboratoryNational Oceanic and Atmospheric AdministrationBoulderUSA
  2. 2.Cooperative Institute for Research in Environmental SciencesUniversity of ColoradoBoulderUSA
  3. 3.Divisions of Geological and Planetary Sciences and Engineering and Applied ScienceCalifornia Institute of TechnologyPasadenaUSA
  4. 4.Global Monitoring Division, Earth System Research LaboratoryNational Oceanic and Atmospheric AdministrationBoulderUSA
  5. 5.Goddard Space Flight CenterNational Aeronautics and Space AdministrationGreenbeltUSA