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| Titel |
Detection of BrO plumes over various sources using OMI and GOME-2
measurements |
| VerfasserIn |
Sora Seo, Andreas Richter, Anne-Marlene Blechschmidt, John P. Burrows |
| 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 |
250149695
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| Publikation (Nr.) |
 EGU/EGU2017-14071.pdf |
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| Zusammenfassung |
| Reactive halogen species (RHS) play important roles in the chemistry of the stratosphere and
troposphere. They are responsible for ozone depletion through catalytic reaction cycles,
changes in the OH/HO2 and NO/NO2 ratios, and oxidation of compounds such as gaseous
elemental mercury (GEM) and dimethyl sulphide (DMS). Thus, monitoring of halogen
oxides is important for understanding global atmospheric oxidation capacity and
climate change. Bromine monoxide (BrO) is one of the most common active halogen
oxides. In the troposphere, large amounts of bromine are detected in Polar Regions in
spring, over salt lakes, and in volcanic plumes. In this study, we analyse BrO column
densities using OMI and GOME-2 observations. The measured spectra from both
UV-visible nadir satellites were analyzed using the differential optical absorption
spectroscopy (DOAS) method with different settings depending on the instrumental
characteristics.
Large amounts of volcanic BrO from the Kasatochi eruption in 2008 were detected for
6 days from August 8 to August 13. Especially large BrO amounts were found
in the plume center for 3 days from August 9 to 11 with slant column densities
(SCD) of up to ∼1.6x1015 molecules cm−2 and ∼5.5x1014 molecules cm−2 in
OMI and GOME-2 measurements, respectively. In addition to the volcanic sources,
events of widespread BrO enhancements were also observed over the Arctic and
Antarctic coastal regions during the spring time by both satellites. As the overpass time
of the two instruments is not the same, differences between the two data sets are
expected. In this study, the agreement between OMI and GOME-2 BrO data is
investigated using both the operational products and different DOAS fits. Systematic
differences are found in BrO slant columns and fitting residuals, both being larger
in the case of OMI data. In addition, results are sensitive to the choice of fitting
window.
From a monitoring point of view, due to the higher spatial resolution of OMI compared to
GOME-2, OMI results are better suited for observing the shape variation and transport
pattern of volcanic BrO. This will be further improved with upcoming the European Sentinel
5 Precursor satellite which has an even higher spatial resolution (3.5 / 7x7 km2). |
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