Latitudinal and vertical distribution of bromine monoxide in the lower stratosphere from Scanning Imaging Absorption Spectrometer for Atmospheric Chartography limb scattering measurements

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Read Full Article (file size: 2063882 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, D14301, doi:10.1029/2005JD006479, 2006 Latitudinal and vertical distribution of bromine monoxide in the lower stratosphere from Scanning Imaging Absorption Spectrometer for Atmospheric Chartography limb scattering measurements C. E. Sioris Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA L. J. Kovalenko Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA C. A. McLinden Meteorological Service of Canada, Environment Canada, Toronto, Ontario, Canada R. J. Salawitch Jet Propulsion Laboratory, Pasadena, California, USA M. Van Roozendael Belgian Institute for Space Aeronomy, Brussels, Belgium F. Goutail Service d'Aéronomie, Centre National de la Recherche Scientifique, Verrières-le-Buisson, France M. Dorf Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany K. Pfeilsticker Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany K. Chance Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA C. von Savigny Institute of Environmental Physics, University of Bremen, Bremen, Germany X. Liu Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA T. P. Kurosu Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA J.-P. Pommereau Service d'Aéronomie, Centre National de la Recherche Scientifique, Verrières-le-Buisson, France H. Bösch Jet Propulsion Laboratory, Pasadena, California, USA J. Frerick European Space Agency/European Space Research and Technology Centre, Noordwijk, Netherlands Abstract Vertical profiles of stratospheric bromine monoxide (BrO) in the 15–30 km range are retrieved from SCIAMACHY limb scatter data over the globe. First validation comparisons with the balloon-borne SAOZ-BrO and LPMA/DOAS instruments indicate retrieval biases of ∼20% or less. Propagated spectral fitting uncertainties lead to a precision approaching ∼25% on a 2 km grid at 25 km. This worsens at higher altitudes because of reduced signal and at lower altitudes because of the reduced penetrability of the atmosphere. In terms of volume mixing ratio (VMR), the single profile precision increases from ∼4 pptv at 17 km to ∼8 pptv at 27 km. Repeatability, an alternative indicator of precision, is 2–3 pptv for SCIAMACHY retrievals and independent of altitude. The BrO stratospheric number density peak generally lies 5 ± 2 km above the tropopause. In the tropics, the stratospheric BrO VMR generally increases with increasing altitude. The observed stratospheric BrO global distribution is generally consistent with previous balloon measurements but does not agree well with results of a model that uses Br_y inferred only from the observed breakdown of long-lived bromoalkanes (i.e., methyl bromide and halons). We find best agreement with the observed vertical and latitudinal distribution of BrO for model results that include an 8.4 ± 2 pptv contribution to stratospheric Br_y, most of which is expected from the breakdown of VSL (very short lived) bromocarbons, in addition to the ∼16 pptv contribution from longer-lived sources. This suggests that stratospheric Br_y exceeds 20 pptv. Profiles of Br_y profiles derived from the balloon measurements of BrO also suggest Br_y is in excess of 20 pptv, but the uncertainty and variability of these results do not allow us to definitively rule out this concentration. We find typical BrO VMRs of ∼4 pptv at 15 km in the tropical tropopause layer, suggesting that a significant portion of the bromine from VSL bromoalkane sources may be carried across the tropopause in the form of inorganic decomposition products. We discuss a variety of VSL bromocarbons species that may be contributing to the elevated concentrations of stratospheric BrO. Received 13 July 2005; accepted 24 April 2006; published 19 July 2006. Keywords: inorganic bromine; stratospheric; limb scattering. Index Terms: 3360 Atmospheric Processes: Remote sensing; 0340 Atmospheric Composition and Structure: Middle atmosphere: composition and chemistry; 0317 Atmospheric Composition and Structure: Chemical kinetic and photochemical properties. Read Full Article (file size: 2063882 bytes) Cited by Citation: Sioris, C. E., et al. (2006), Latitudinal and vertical distribution of bromine monoxide in the lower stratosphere from Scanning Imaging Absorption Spectrometer for Atmospheric Chartography limb scattering measurements, J. Geophys. Res., 111, D14301, doi:10.1029/2005JD006479. Copyright 2006 by the American Geophysical Union.

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