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| Titel |
Northern Hemisphere stratospheric winds in higher midlatitudes: longitudinal distribution and long-term trends |
| VerfasserIn |
M. Kozubek, P. Križan, J. Laštovička |
| 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 ; 15, no. 4 ; Nr. 15, no. 4 (2015-02-27), S.2203-2213 |
| Datensatznummer |
250119468
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| Publikation (Nr.) |
 copernicus.org/acp-15-2203-2015.pdf |
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| Zusammenfassung |
| The Brewer–Dobson circulation (mainly meridional circulation) is very
important for stratospheric ozone dynamics and thus for the overall state
of the stratosphere. There are some indications that the meridional
circulation in the stratosphere could be longitudinally dependent, which
would have an impact on the ozone distribution. Therefore, we analyse here
the meridional component of the stratospheric wind at northern middle
latitudes to study its longitudinal dependence. The analysis is based on the
NCEP/NCAR-1 (National Centers for Environmental Prediction and the National
Center for Atmospheric Research), MERRA (Modern Era-Retrospective
Analysis) and ERA-Interim (European Centre for Medium-Range Weather
Forecasts (ECMWF) Re-Analysis Interim) reanalysis data. The well-developed
two-core structure of strong but opposite meridional winds, one in each
hemisphere at 10 hPa at higher northern middle latitudes, and a
less pronounced five-core structure at 100 hPa are identified. In the
central areas of the two-core structure the meridional and zonal wind
magnitudes are comparable. The two-core structure at 10 hPa is almost
identical for all three different reanalysis data sets in spite of the
different time periods covered. The two-core structure is not associated
with tides. However, the two-core structure at the 10 hPa level is related
to the Aleutian pressure high at 10 hPa. Zonal wind, temperature and the
ozone mixing ratio at 10 hPa also exhibit the effect of the Aleutian high,
which thus affects all parameters of the Northern Hemisphere middle
stratosphere. Long-term trends in the meridional wind in the "core" areas
are significant at the 99% level. Trends of meridional winds are negative
during the period of ozone depletion development (1970–1995), while they are
positive after the ozone trend turnaround (1996–2012). Meridional wind
trends are independent of the sudden stratospheric warming (SSW) occurrence
and the quasi-biennial oscillation (QBO) phase. The influence of the 11-year
solar cycle on stratospheric winds has been identified only during the west
phase of QBO. The well-developed two-core structure in the meridional wind
illustrates the limitations of application of the zonal mean concept in
studying stratospheric circulation. |
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