Abstract:Using the GPS low level sounding data obtained in the dam area of Xiluodu Hydropower Station and the reservoir area of Xiangjiaba Hydropower Station in the lower reaches of Jinsha River as well as the synchronous surface observation data, this paper analyzes the variation characteristics of the wind fields in different heights from surface to the 2000 m height of atmospheric boundary layer in spring, summer, autumn and winter. The results indicate that: (1) in spring westerly winds blow in the atmospheric boundary layer over Xiluodu Dam Area mainly while under the height of 1500 m calm and light winds appear more frequently, reaching the maximum values of surface calm and light winds in the four seasons; (2) in summer the occurrence of surface calm and light winds is the least in the four seasons, and west winds and northwest west winds prevail in the middle and lower levels of atmospheric boundary layer; (3) in autumn westerly winds are the major theme in the middle and lower levels over Xiluodu Dam Area but turn to northerly winds gradually in the upper level; (4) in winter wersterlies dominated by west and northwest west winds prevail in the low level whilst in the middle and high levels the directions of winds become west, southwest west, east and northeast east; (5) in autumn and winter the maximum wind speeds of west, northeast north, northeast east in the atmosphere boundary layer over Xiluodu Dam Area all appear in the high level of 2000 m.