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| Titel |
Conventional measurement data: good enough for offshore meteorology? |
| VerfasserIn |
Michael Schmidt, Jens Tambke, Gerald Steinfeld, Detlev Heinemann |
| 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 |
250097144
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| Publikation (Nr.) |
 EGU/EGU2014-12691.pdf |
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| Zusammenfassung |
| The analysis of marine boundary layer properties is an fundamental task of energy
meteorology. The determination of atmospheric stability and momentum fluxes out of
measurement data is, for example, important for the validation of mesoscale models such as
WRF and COSMO, but also for the validation of microscale models like PALM large
eddy simulations. From them, major conclusions are drawn for the design of wind
turbines and the layout design of entire offshore wind farms with 20 to more than 100
turbines.
Up to now, high-resolution measurements of the vertical wind are usually carried out with
sonic anemometers, which are known to provide simultaneously (sound-) temperature
signals. Recent investigations of data from different met masts in the North Sea have revealed
errors now, which can be corrected only partially. A method will be shown for visualization
of a sonic anemometers influence on the mean vertical wind speed and how it can be
adjusted.
Another sonic anemometer dysfunction, the striking, not by meteorology explainable
underestimation of vertical wind events for lots of fine wind direction segments can only be
demonstrated so far, but not explained or actually corrected.
The quality of sonic anemometer measurements of mean temperatures is proved to be poor to
mediocre – depending on the type of the device. Furthermore, there is no evidence about the
quality of the high-frequency temperature fluctuation measurements, simply because
comparative measurements are missing. Temperature measurements with sonic anemometers
under controlled laboratory conditions and comparisons with other fast temperature
measurements techniques must be performed in order to gain more certainty on this
issue.
Temperature difference sensors are producing data in agreement with theory. Such a
sensor is already installed on a North Sea met mast. Some new temperature difference sensor
results will be presented.
New methods, especially for high-frequency and high-quality measurements of vertical wind
speeds, have to be developed in the very near future for serving the high and increasing needs
of modelers. |
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