First middle-atmospheric zonal wind profile measurements with a new ground-based microwave Doppler-spectro-radiometer

Rüfenacht, Rolf; Kämpfer, Niklaus; Murk, Axel (2012). First middle-atmospheric zonal wind profile measurements with a new ground-based microwave Doppler-spectro-radiometer. Atmospheric Measurement Techniques (AMT), 5(11), pp. 2647-2659. Göttingen: Copernicus Publications 10.5194/amt-5-2647-2012

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We report on the wind radiometer WIRA, a new ground-based microwave Doppler-spectro-radiometer specifically designed for the measurement of middle-atmospheric horizontal wind by observing ozone emission spectra at 142.17504 GHz. Currently, wind speeds in five levels between 30 and 79 km can be retrieved which makes WIRA the first instrument able to continuously measure horizontal wind in this altitude range. For an integration time of one day the measurement error on each level lies at around 25 m s−1. With a planned upgrade this value is expected to be reduced by a factor of 2 in the near future. On the altitude levels where our measurement can be compared to wind data from the European Centre for Medium-Range Weather Forecasts (ECMWF) very good agreement in the long-term statistics as well as in short time structures with a duration of a few days has been found. WIRA uses a passive double sideband heterodyne receiver together with a digital Fourier transform spectrometer for the data acquisition. A big advantage of the radiometric approach is that such instruments can also operate under adverse weather conditions and thus provide a continuous time series for the given location. The optics enables the instrument to scan a wide range of azimuth angles including the directions east, west, north, and south for zonal and meridional wind measurements. The design of the radiometer is fairly compact and its calibration does not rely on liquid nitrogen which 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. In the present paper, a description of the instrument is given, and the techniques used for the wind retrieval based on the determination of the Doppler shift of the measured atmospheric ozone emission spectra are outlined. Their reliability was tested using Monte Carlo simulations. Finally, a time series of 11 months of zonal wind measurements over Bern (46°57′ N, 7°26′ E) is presented and compared to ECMWF wind data.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Applied Physics

UniBE Contributor:

Rüfenacht, Rolf and Kämpfer, Niklaus

ISSN:

1867-1381

Publisher:

Copernicus Publications

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:43

Last Modified:

24 Dec 2014 00:19

Publisher DOI:

10.5194/amt-5-2647-2012

Web of Science ID:

000311804400008

BORIS DOI:

10.7892/boris.17893

URI:

https://boris.unibe.ch/id/eprint/17893 (FactScience: 225730)

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