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| Titel |
Measurement of horizontal wind in the middle atmosphere (30-80 km) by the submillimeter limb sounder SMILES. |
| VerfasserIn |
P. Baron, D. Murtagh, J. Urban, S. Ochiai, H. Sagawa, K. Kikuchi, Y. Kasai |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250064626
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| Zusammenfassung |
| Atmospheric wind field measurements are mostly limited to the troposphere although
mesospheric winds are measured using optical techniques from satellites and by radar
systems such as EISCAT and various meteor radars. Stratospheric winds are computed in
meteorological models using mass balance considerations where the pressure and
temperature fields are assumed to be in balance with the Coriolis force. Here we report the
first global observations of winds in the mid/upper stratosphere using the SMILES sub-mm
radiometer that was launched in September 2009. SMILES operated from the Japanese
Experiment Module on the International Space Station until April 2010. We have exploited its
high frequency resolution and signal-to-noise ratio to derive the small Doppler shifts in the
atmospheric spectra and thereby line-of-sight wind velocities. Wind information is derived
from 35–80 km and from 40°S–65°N with uncertainties ~10 ms-1 between 35 and 50 km.
Both zonal and meridional components are measured (not simultaneously). The comparison
with the ECMWF analysis in the extra-tropical stratosphere, is consistent with the
measurement error. A slight increase of the ECMWF error (~5 ms-1) in the Tropics where
the thermal wind hypothesis is not valid, is also noticed. Although the instrument was
not designed for this purpose, these observations demonstrate that sub-mm wave
radiometers have the potential to fill the altitude gap in atmospheric wind measurements. |
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