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| Titel |
First continuous time series of tropical, mid-latitudinal and polar middle-atmospheric wind profile measurements with a ground-based microwave Doppler-spectro-radiometer |
| VerfasserIn |
Rolf Rüfenacht, Niklaus Kämpfer, Axel Murk, Patrick Eriksson, Stefan A. Buehler, Rigel Kivi, Philippe Keckhut, Alain Hauchecorne, Valentin Duflot |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096042
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| Publikation (Nr.) |
 EGU/EGU2014-11522.pdf |
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| Zusammenfassung |
| Wind is one of the key parameters for the characterisation of the atmosphere and the
understanding of its dynamics. Despite this, no continuously operating instrument for
wind measurements in the upper stratosphere and lower mesosphere existed so
far.
Aiming to contribute to the closing of this data gap by exploiting the potential of
microwave radiometry the Institute of Applied Physics of the University of Bern built a
ground-based 142 GHz Doppler-spectro-radiometer with the acronym WIRA (WInd
RAdiometer). WIRA is specifically designed for the measurement of middle-atmospheric
horizontal wind and is sensitive to the altitude range between 35 and 70 km. The architecture
of the radiometer is fairly compact what makes it transportable and suitable for campaign use.
WIRA is conceived in a way that it can be operated remotely and does hardly require any
maintenance.
The operational use of WIRA started in September 2010. Since a technical upgrade in
autumn 2012 which drastically increased the signal to noise ratio of the instrument, the
meridional component is permanently measured along with the zonal wind to get a full
picture of the horizontal wind field.
During the last year the wind retrieval algorithm has been entirely rebuilt and tested. It is
now based on the optimal estimation technique (OEM) and uses an upgraded version of the
ARTS/QPACK radiative transfer and inversion model.
Time series of middle-atmospheric wind from measurement campaigns of 7 to 11 months
duration at mid and high latitude sites (Bern, 46°57′N, 7°26′E; Sodankylä, 67°22′N,
26°38′E; Observatoire de Haute-Provence, 43°56′N, 5°43′E) have been obtained. In
September 2013 WIRA was moved to Observatoire du Maïdo (21°04′S, 55°23′E) to
study the dynamics of the tropical middle atmosphere. The measurements have
been compared to the data from the ECMWF model. Generally good agreement
has been found in the stratosphere, however systematic discrepancies exist in the
mesosphere.
At the conference, the main results from the measurement campaigns and the comparison
of the ECMWF model data with these measurements will be presented after a short
introduction to the measurement technique. |
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