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| Titel |
Corrections of wind measurements on a moving boat with a smartphone |
| VerfasserIn |
D. Schlabing, M. Eder, R. Lutz, J. Seidel |
| 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 |
250069526
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| Zusammenfassung |
| Wind is one of the main driving forces for circulation in lakes. Various studies concerning
Lake Constance (northern foot of the Alps) used hydrodynamic models which rely on this
meteorological variable as input. However, while wind measurements on shore are available,
there is hardly any information about wind on Lake Constance itself. Furthermore the
installation of measurement buoys is expensive and can lead to conflicts with fishery or
shipping for example.
The latter provides a solution for this problem, because ships can be used as
platforms for measurements. In our case, we used a 3D ultra-sonic anemometer
(USA) on a research vessel of the Institute for Lake Research (ISF) in Langenargen
(Germany) to conduct wind measurements. Since the USA provides data with a time
resolution of up to 32Hz and the wavering motion of the boat was visible in the velocity
measurements, there was a need to correct the data. This was done by using the 3D
accelerometer of a smartphone with the same measurement frequency of the USA,
which was attached just below the anemometer. The apparent wind speed was also
corrected for the speed and heading of the vessel using GPS and digital compass
data.
In principle, measured object velocity vectors, obtained by integrating the measured
acceleration, are diametrically opposed to the apparent wind caused by the movement of the
instrument. This means that the correction is simply a matter of adding the corresponding
velocity vectors. While a first test under “laboratory”-conditions confirmed the idea of
the method, the application in the field turned out to be not as straight forward. |
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