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Wind stress and surface roughness at air-sea interface
- Source :
- Journal of Geophysical Research. 74:444-455
- Publication Year :
- 1969
- Publisher :
- American Geophysical Union (AGU), 1969.
-
Abstract
- Based on the compiled data of thirty independent oceanic observations, this article systematically presents the wind-stress coefficient, the surface roughness, and the boundary layer flow regime at the air-sea interface under various wind conditions. The air flow near the water surface is shown to be aerodynamically rough or in the transition region except at a very low wind velocity (U10 < 3 m/sec). Both the wind-stress coefficient and the surface roughness are found to increase with the wind velocity when U10 is less than 15 m/sec and to reach a saturated value for U10 greater than 15 m/sec. From the oceanic wave observations, the presence of this discontinuity at U10 = 15 m/sec is found to be due to an increase in the wind velocity (measured at the significant wave amplitude above the mean water level) beyond the average wave phase velocity. This finding provides a well-defined separation for the often quoted terms ‘light’ and ‘strong’ winds. The compiled data also show that the surface roughness is governed by the amplitude of the short gravity waves. Charnock's relationship is shown to be applicable to most of the oceanic data and Charnock's proportionality constant is determined, η/(u*2/g) = 0.0156. Finally, two approximate formulas for the windstress coefficient C10 = 0.5 × U101/2 × 10−3 for light wind and C10 = 2.6 × 10−3 for strong wind are suggested for oceanic applications.
- Subjects :
- Physics
Atmospheric Science
Ecology
Paleontology
Soil Science
Wind stress
Forestry
Geometry
Geophysics
Aquatic Science
Oceanography
Wind speed
Boundary layer
Roughness length
Amplitude
Space and Planetary Science
Geochemistry and Petrology
Drag
Wind wave
Earth and Planetary Sciences (miscellaneous)
Surface roughness
Earth-Surface Processes
Water Science and Technology
Subjects
Details
- ISSN :
- 01480227
- Volume :
- 74
- Database :
- OpenAIRE
- Journal :
- Journal of Geophysical Research
- Accession number :
- edsair.doi...........4ef2e1f707abf20f400aea25d6927f98