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| Titel |
Bromine partitioning in the tropical tropopause layer: implications for stratospheric injection |
| VerfasserIn |
R. P. Fernandez, R. J. Salawitch, D. E. Kinnison, J.-F. Lamarque, A. Saiz-Lopez |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 24 ; Nr. 14, no. 24 (2014-12-16), S.13391-13410 |
| Datensatznummer |
250119244
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| Publikation (Nr.) |
 copernicus.org/acp-14-13391-2014.pdf |
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| Zusammenfassung |
| Very short-lived (VSL) bromocarbons are produced at a prodigious rate by
ocean biology and these source compounds (SGVSL), together with their
inorganic degradation products (PGVSL), are lofted by vigorous
convection to the tropical tropopause layer (TTL). Using a state-of-the-art
photochemical mechanism within a global model, we calculate annual average
stratospheric injection of total bromine due to VSL sources to be 5 pptv (parts per trillion by volume),
with ~ 3 pptv entering the stratosphere as PGVSL and
~ 2 pptv as SGVSL. The geographic distribution and
partitioning of VSL bromine within the TTL, and its consequent stratospheric
injection, is highly dependent on the oceanic flux, the strength of
convection and the occurrence of heterogeneous recycling reactions. Our
calculations indicate atomic Br should be the dominant inorganic species in
large regions of the TTL during daytime, due to the low ozone and cold
conditions of this region. We propose the existence of a "tropical ring of
atomic bromine" located approximately between 15 and 19 km and
between 30° N and 30° S. Daytime Br / BrO ratios of up
to ~ 4 are predicted within this inhomogeneous ring in regions
of highly convective transport, such as the tropical Western Pacific. Therefore,
we suggest that experimental programs designed to quantify the bromine budget of
the TTL and the stratospheric injection of VSL biogenic bromocarbons should
include a strategy for the measurement of atomic Br during daytime as well as HOBr and BrCl during nighttime. |
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