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| Titel |
Trend analysis of stratospheric BrO using ground-based UV-visible and SCIAMACHY limb observations at 60°N, 44°N, 28°N, and 45°S |
| VerfasserIn |
F. Hendrick, A. Rozanov, P. V. Johnston, O. Puentedura, M. De Mazière, M. Gil, K. Kreher, B.-M. Sinnhuber, N. Theys, M. Van Roozendael |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026015
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| Zusammenfassung |
| Recently, we have published a trend analysis of stratospheric bromine monoxide (BrO)
columns derived from ground-based zenith-sky UV-visible observations made from 1995 to
2005 at the NDACC (Network for the Detection of Atmospheric Composition Change)
stations of Harestua (60-N, 11-E) and Lauder (45-S, 170-E). The time series of stratospheric
BrO vertical column densities have been fitted using a statistical model including a linear
trend and seasonal components represented by polyharmonic functions. The inclusion of such
functions in the model enables to fit the strong seasonality of BrO in the stratosphere. At
both stations, the polyharmonic fit gives a positive trend of +2.5%/year for the
1995-2001 period, while a negative trend of -1%/year is found after 2001. Given the
mean age of air over Harestua and Lauder, the decline of BrO in the stratosphere
after 2001 is consistent with the reported decline of long-lived bromine source
gases observed since the second half of 1998. This study provided therefore the first
clear evidence for a decline of the stratospheric bromine loading in response to the
Montreal Protocol limiting the production of brominated and chlorinated source
gases.
In this presentation, we extend the trend analysis at Harestua and Lauder until 2008. We
also include time series of BrO vertical columns retrieved at two other NDACC stations:
Observatoire de Haute Provence (OHP; 44-N, 5.5-E) and IzaÅa (28-N, 16-W). The period
covered by the observations is 1998-2008 for OHP and 2004-2008 for IzaÅa. Moreover, the
trend values at the four NDACC stations are compared to the results of a trend analysis of
time series of collocated stratospheric BrO columns retrieved from SCIAMACHY limb
observations. |
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