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| Titel |
Evaluation of wind profiles from the NERC MST radar, Aberystwyth, UK |
| VerfasserIn |
C. F. Lee, G. Vaughan, D. A. Hooper |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 9 ; Nr. 7, no. 9 (2014-09-24), S.3113-3126 |
| Datensatznummer |
250115909
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| Publikation (Nr.) |
 copernicus.org/amt-7-3113-2014.pdf |
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| Zusammenfassung |
| This study quantifies the uncertainties in winds measured by the Aberystwyth
Mesosphere–Stratosphere–Troposphere (MST) radar (52.4° N,
4.0° W), before and after its renovation in March 2011. A total of 127
radiosondes provide an independent measure of winds. Differences between
radiosonde and radar-measured horizontal winds are correlated with long-term
averages of vertical velocities, suggesting an influence from local mountain
waves. These local influences are an important consideration when using radar
winds as a measure of regional conditions, particularly for numerical weather
prediction. For those applications, local effects represent a source of
sampling error additional to the inherent uncertainties in the measurements
themselves. The radar renovation improved the signal-to-noise ratio (SNR) of measurements, with a
corresponding improvement in altitude coverage. It also corrected an
underestimate of horizontal wind speeds attributed to beam formation
problems, due to pre-renovation component failure. The root mean square error (RMSE) in
radar-measured horizontal wind components, averaged over half an hour,
increases with wind speed and altitude, and is 0.8–2.5 m s−1
(6–12% of wind speed) for post-renovation winds. Pre-renovation values
are typically 0.1 m s−1 larger. The RMSE in radial velocities is
<0.04 m s−1. Eight weeks of special radar operation are used to
investigate the effects of echo power aspect sensitivity. Corrections for
echo power aspect sensitivity remove an underestimate of horizontal wind
speeds; however aspect sensitivity is azimuthally anisotropic at the scale of
routine observations (≈1 h). This anisotropy introduces random
error into wind profiles. For winds averaged over half an hour, the RMSE
is around 3.5% above 8 km, but as large as 4.5% in the
mid-troposphere. |
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