Features of wind field over the sea surface in the coastal area
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In this paper we analyze SAR wind field features, in particular the effects of wind shadowing. These effects represent the dynamics of the internal atmospheric boundary layer, which is formed due to the transition of the air flow arriving from the rough land surface to the “smooth” water surface. In the wind-shadowed area, the flow accelerates, and a surface wind stress increases with fetch. The width of the shadow depends not only on the wind speed and atmospheric boundary layer stratification, but also on geographic features such as windflow multiple transformations over the complex surface land–Lake Chudskoe–land–Gulf of Finland. Measurements showed that, in the area of wind acceleration, the surface stress normalized by an equilibrium value (far from the coast) is a universal function of dimensionless fetch Xf/G. Surface wind stress reaches an equilibrium value at Xf/G ≈ 0.4, which is the scale of the planetary-boundary-layer relaxation.
Keywordswind transformation coastal area internal boundary layer SAR Gulf of Finland
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- 3.G. S. Raynor, P. Michael, R. M. Brown, and S. Sethurman, “Studies of atmospheric diffusion from nearshore oceanic site,” J. Appl. Meteorol. 7, 331–348 (1975).Google Scholar
- 5.V. N. Kudryavtsev, V. K. Makin, A. M. G. Klein Tank, and J. W. Verkaik, “A model of wind transformation over water–land surfaces,” Sci. Rep. De Bilt 1 (2001).Google Scholar
- 6.R. C. Beal, G. S. Young, F. Monaldo, et al., High Resolution Wind Monitoring with Wide Swath SAR: AUser’s Guide (U.S. Department of Commerce, Washington, D.C., 2005).Google Scholar
- 7.W. Alpers, A. Mouche, A. Y. Ivanov, and B. Brummer, “High resolution wind fields over the Black Sea derived from Envisat ASAR data using an advanced wind retrieval algorithm,” in Proceedings of the 4th International Workshop Sea SAR 2012, Tromsö, Norway, 18–22 June 2012, 2013, ESA SP-709, pp. 239–248.Google Scholar
- 8.H. Hersbach, “CMOD5.N: A C-band geophysical model function for equivalent neutral wind,” ECMWF Tech. Memo. 554 (2008).Google Scholar
- 10.N. Wiener, Extrapolation, Interpretation, and Smoothing of Stationary Time Series with Engineering Application (M.I.T. Press and John Wiley and Sons, New York, 1949).Google Scholar