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  • Author or Editor: Roseanne D. Diab x
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Fedor F. Bryukhan and Roseanne D. Diab

Abstract

On the basis of daily ECMWF data over the period 1982–89, the mean seasonal and mean annual wind energy resource fields on the isobaric surfaces 1000, 850, 700, 500, 300, 200, and 100 hPa, within the latitude–longitudinal zone 0°–50°S and 0°–45°E, have been calculated and analyzed. Generally, maximum wind energy is recorded on the 3OO-hPa surface, and the intensities are greater by about 25%–30% in winter than in summer. The greatest continental wind energy resources are experienced over the southern tip of the southern African subcontinent, where it was established that the free atmospheric resources exceed those near the surface by at least an order of magnitude. The two-dimensional Gaussian distribution of the wind vector has been used to provide an indirect estimate of the wind energy resource. Good agreement between this measure and the direct estimate of wind energy was obtained, demonstrating the potential usefulness of the two-dimensional Gaussian distribution in estimating upper-air wind energy resources.

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Mark R. Jury, Roseanne D. Diab, and Mark Schormann

Abstract

Aircraft surveys have been conducted to assess the mesoscale pattern of wind and weather over Cape Saint Francis, South Africa, on the southern tip of the African continent. Ten surveys were flown at a level of 100 m above ground during November 1991, and wind velocity, turbulence, and temperature were monitored. Results were stratified into composites according to the mean direction and speed of the wind. Under the prevailing westerly wind, three areas of high speed were found that may constitute optimal sites for wind energy turbines. These areas of high velocities lie along the tops of low rolling hills in the vicinity of the Krom River at Cape Saint Francis. The usefulness of aircraft surveys in developing an understanding of the mesoscale pattern of winds and associated meteorological fields is emphasized.

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