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| Titel |
Reduction of wind stress due to swell at high wind conditions |
| VerfasserIn |
Hector García-Nava, Francisco J. Ocampo-Torres |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046165
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| Zusammenfassung |
| Wind stress over the ocean depends on the sea surface roughness which is determined by the
sea state. Underdeveloped wind-seas, rougher than their fully developed counterpart, have
been associated with increased drag. The presence of swell can modify wind stress by
exchanging momentum with the air flow and by modifying the wind-sea roughness. The
former mechanism, important at low wind speeds, increases or reduces the drag depending on
the swell relative direction of propagation. The latter mechanism, less studied and poorly
understood, is believed to have a greater impact at high winds whenever underdeveloped local
waves coexist with swell. Detailed measurements of wind stress and wave field in
fetch-limited conditions were made in an area subjected to strong and persistent winds.
Through modeling and analysis of the observations it is found that swell reduces
the drag at winds as high as 20 ms-1. The reduction of wind stress seems to be
caused by a decrease of energy levels on the high frequency part of the wind-sea
spectrum. |
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