Determination of wind direction and speed from free atmosphere data

4 Abstract Determination of wind direction and speed from free atmosphere data. This work deals with relationship between surface wind and large-scale predictors in the Czech Republic. Approach is statistical downscaling based on multiple linear regression with stepwise screening. Tested predictors include four geopotential heights (hgt 500, hgt 700, hgt 850 and hgt 1000), sea level pressure and surface wind components U and V. Observed surface wind speed and azimuth from 18 meteorological station ČHMÚ is used as predictand. Period of interest is define by used data on term 1961 - 2010. In three different methods are compared straight downscaling of wind components U and V, used wind speed calculate from downscaled components U and V, and straight downscaling of wind speed without distinguish wind direction. Resulting models are tested by cross-validation method. The resulting equation allows good simulation of surface wind at most of station. The better method to downscaling surface wind speed is prescribe method of calculate wind speed from downscaled components U and V