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| Titel |
Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009-2010 |
| VerfasserIn |
P. Baron, D. P. Murtagh, J. Urban, H. Sagawa, S. Ochiai, Y. Kasai, K. Kikuchi, F. Khosrawi, H. Körnich, S. Mizobuchi, K. Sagi, M. Yasui |
| 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 ; 13, no. 12 ; Nr. 13, no. 12 (2013-06-25), S.6049-6064 |
| Datensatznummer |
250018719
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| Publikation (Nr.) |
 copernicus.org/acp-13-6049-2013.pdf |
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| Zusammenfassung |
| Although the links between stratospheric dynamics, climate and weather
have been demonstrated, direct observations of stratospheric winds are
lacking, in particular at altitudes above 30 km.
We report observations of winds between 8 and
0.01 hPa (~35–80 km) from October 2009 to April
2010 by the Superconducting Submillimeter-Wave Limb-Emission Sounder
(SMILES) on the International Space Station. The altitude range covers
the region between 35–60 km where previous space-borne wind
instruments show a lack of sensitivity. Both zonal and meridional
wind components were obtained, though not simultaneously, in the
latitude range from 30° S to 55° N and with a single
profile precision of 7–9 m s–1 between 8 and
0.6 hPa and better than 20 m s–1 at altitudes above.
The vertical resolution is 5–7 km except in the upper part of
the retrieval range (10 km at 0.01 hPa). In the region
between 1–0.05 hPa,
an absolute value of the
mean difference < 2 m s–1 is
found between SMILES profiles retrieved from different spectroscopic
lines and instrumental settings. Good agreement
(absolute value of the
mean difference of ~2 m s–1) is also found with the
European Centre for
Medium-Range Weather Forecasts (ECMWF) analysis in most of the
stratosphere except for the zonal winds over the equator
(difference > 5 m s−1). In the mesosphere, SMILES and
ECMWF zonal winds exhibit large differences (> 20 m s–1),
especially in the tropics. We illustrate our results by showing daily
and monthly zonal wind variations, namely the semi-annual oscillation
in the tropics and reversals of the flow direction between
50–55° N during sudden stratospheric warmings.
The daily comparison with ECMWF winds reveals that
in the beginning of February, a significantly stronger zonal westward
flow is measured in the tropics at 2 hPa compared to the flow
computed in the analysis (difference of ~20 m s–1).
The results show that the comparison between SMILES and ECMWF winds is
not only relevant for the quality assessment of the new SMILES winds,
but it also provides insights on the quality of the ECMWF winds
themselves. Although the instrument was not specifically designed for
measuring winds, the results demonstrate that space-borne sub-mm wave
radiometers have the potential to provide good quality data for
improving the stratospheric winds in atmospheric models. |
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