Abstract:Based on the data of air sounding winds from 93 high-altitude meteorological stations (300 m, 600 m and 900 m above the radar) in China from 1981 to 2014, the spatio-temporal variations of wind speed and its trends at different heights in the boundary layer were analyzed using GIS. The following conclusions were obtained. At the height of 300-900 m, the average wind speed over the years in Northeast and North China is larger, while the mean annual wind speed in Southwest and Northwest China is small relatively. The monthly variation trends of average wind speeds at different heights over the same area in the boundary layer are basically the same, but the seasonal wind speed variations in different regions are different. The annual range of monthly average wind speed in the same region increases with altitude. The annual average wind speed at 300 m altitude decreases significantly. At 600 m and 900 m heights, the average annual wind speeds in North China, Northwest China and Central China show an upward trend while the average annual wind speed in Northeast China shows a decreasing trend, but none of them have passed the significance level tests. The spatial distribution of average annual wind speed at all altitudes is relatively large in Northeast China, especially in the Greater Khingan Mountains and the Northeast Plain. The wind speed from east to west gradually decreases from the coast to the inland. At 300 m height, the annual average wind speed across China shows mainly a decreasing trend. At 600 m height, annual average wind speed in most parts of China shows an increasing trend, especially in Central China, Northwest China and the eastern coastal areas. At 900 m height, the change in annual average wind speed nationwide shows an encircling trend from the boundary to the interior, with the central area showing an increasing trend and the border areas a downward trend. However, not many areas have passed the significance level tests.