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| Titel |
Forecasts and assimilation experiments of the Antarctic ozone hole 2008 |
| VerfasserIn |
J. Flemming, A. Inness, L. Jones, H. J. Eskes, V. Huijnen, M. G. Schultz, O. Stein, D. Cariolle, D. Kinnison, G. Brasseur |
| 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 ; 11, no. 5 ; Nr. 11, no. 5 (2011-03-03), S.1961-1977 |
| Datensatznummer |
250009441
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| Publikation (Nr.) |
 copernicus.org/acp-11-1961-2011.pdf |
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| Zusammenfassung |
| The 2008 Antarctic ozone hole was one of the largest and most long-lived in
recent years. Predictions of the ozone hole were made in near-real time
(NRT) and hindcast mode with the Integrated Forecast System (IFS) of the
European Centre for Medium-Range Weather Forecasts (ECMWF). The forecasts
were carried out both with and without assimilation of satellite
observations from multiple instruments to provide more realistic initial
conditions. Three different chemistry schemes were applied for the
description of stratospheric ozone chemistry: (i) a linearization of the
ozone chemistry, (ii) the stratospheric chemical mechanism of the Model of
Ozone and Related Chemical Tracers, version 3, (MOZART-3) and (iii) the
relaxation to climatology as implemented in the Transport Model, version 5,
(TM5). The IFS uses the latter two schemes by means of a two-way coupled
system. Without assimilation, the forecasts showed model-specific
shortcomings in predicting start time, extent and duration of the ozone
hole. The assimilation of satellite observations from the Microwave Limb
Sounder (MLS), the Ozone Monitoring Instrument (OMI), the Solar
Backscattering Ultraviolet radiometer (SBUV-2) and the SCanning Imaging
Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) led to a
significant improvement of the forecasts when compared with total columns
and vertical profiles from ozone sondes. The combined assimilation of
observations from multiple instruments helped to overcome limitations of the
ultraviolet (UV) sensors at low solar elevation over Antarctica. The
assimilation of data from MLS was crucial to obtain a good agreement with
the observed ozone profiles both in the polar stratosphere and troposphere.
The ozone analyses by the three model configurations were very similar
despite the different underlying chemistry schemes. Using ozone analyses as
initial conditions had a very beneficial but variable effect on the
predictability of the ozone hole over 15 days. The initialized forecasts
with the MOZART-3 chemistry produced the best predictions of the increasing
ozone hole whereas the linear scheme showed the best results during the
ozonehole closure. |
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