| Based on the climatic data of 61 meteorological stations in Hebei Province, monthly mean northern hemisphere circulation index data and NCEP/NCAR monthly mean reanalysis data from 1961 to 2007, using line lean estimate, related analysis, mutation analysis, wavelet analysis, synthesization analysis, the thesis studies the wind velocity change characteristic in Hebei and its influence factors. The results showed that:(1) The ground wind velocity in spring is biggest, the ground wind velocity in summer and in autumn is least. The ground wind velocity in the northwest of Zhangjiakou is biggest. The wind in Hebei Plain and the east area of Hebei along the coast is bigger, the wind in the basin of Mount Yanshan is least. The ground wind velocity in the city is less than that in the suburb. (2) The ground wind velocity in spring, summer, autumn and winter all presents unanimously descending trend in Hebei province between 1961 and 2007. The descending speed in spring and winter is more quickly than that in summer and in autumn. The wind descend more quickly in the area where average wind is bigger. (3) The wind velocity variability in Hebei display some decadal and interannual oscillation cycle. (4) While the cold air influence of 500hPa is stronger, the wind velocity of spring, autumn and winter is stronger. While the cold air influence of 500hPa is stronger and the western Pacific subtropical high reduces eastward, the wind velocity of summer is stronger. (5) The East Asia monsoon, the Arctic oscillation and the contemporaneous northern hemisphere subtropical high area have obvious influences on wind velocity. (6) In spring, summer and autumn, the sunshine number and daily temperature range is bigger, the convection is strong, the wind of Hebei is stronger.
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