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| Titel |
Diurnal variations of BrONO2 observed by MIPAS-B in the Arctic, at mid-latitudes, and in the Tropics |
| VerfasserIn |
Gerald Wetzel, Hermann Oelhaf, Michael Höpfner, Felix Friedl-Vallon, Andreas Ebersoldt, Thomas Gulde, Sebastian Kazarski, Oliver Kirner, Anne Kleinert, Guido Maucher, Hans Nordmeyer, Johannes Orphal, Roland Ruhnke, Björn-Martin Sinnhuber |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143276
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| Publikation (Nr.) |
 EGU/EGU2017-6982.pdf |
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| Zusammenfassung |
| Despite being much less abundant, the contribution of bromine to stratospheric ozone
depletion is similar to that of chlorine. Moreover, against the background of abating levels of
chlorine in the stratosphere, bromine is important due to its natural sources. The two major
inorganic bromine (Bry) species in the lower stratosphere are bromine oxide (BrO) and
bromine nitrate (BrONO2). The relative abundances of these molecules are mainly controlled
by photochemical processes.
The first stratospheric measurements of the diurnal variation of BrONO2 around sunrise
and sunset are reported. Arctic flights of the balloon-borne Michelson Interferometer for
Passive Atmospheric Sounding (MIPAS-B) were carried out from Kiruna (68∘N,
Sweden) inside the stratospheric polar vortices in January 2010 and March 2011
where diurnal variations of BrONO2 around sunrise have been observed. High
nighttime BrONO2 volume mixing ratios of up to 22 parts per trillion by volume (pptv)
were detected in the late winter 2011 in the absence of polar stratospheric clouds
(PSC). In contrast, the amount of measured BrONO2 was significantly lower in
January 2010 partly due to heterogeneous destruction of BrONO2 on PSC particles. A
further balloon flight took place at mid-latitudes from Timmins (49∘N, Canada)
in September 2014. Mean BrONO2 mixing ratios of 23 pptv were observed after
sunset in the altitude region between 22 and 29 km. Day- and nighttime profiles of
BrONO2 were also inferred from limb emission spectra recorded during a tropical
balloon flight from Teresina (5∘S, Brazil). Significant differences of the stratospheric
BrONO2 amount with up to 23 pptv during night and up to 12 pptv during day were
found.
Measurements are discussed in comparison to a multi-year simulation performed with the
Chemistry Climate Model EMAC (ECHAM5/MESSy Atmospheric Chemistry). The
combination of model simulations with MIPAS-B measurements gives an estimate of
stratospheric total inorganic bromine. |
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