Abstract:

Using the data measured by a new-generation L-band upper-air meteorological radar in Jiyuan, He'nan province from January of 2007 to December of 2020, the characteristics of the tropospheric wind field in Jiyuan were analyzed.The results showed that the average wind speed below 10000 m in Jiyuan has a single increase trend with height, which is relatively severe in winter and relatively gentle in summer.From January, the horizontal wind speed of each layer in Jiyuan, especially the troposphere above 1000 m, gradually decreases, that is, the height of the strong wind area continues to rise.From June to September, the wind speed of each layer is relatively small, and then it gradually increases from October and the height of the strong wind area keeps dropping.The proportion of wind speed below 10 m·s^-1 in the troposphere shows a single decreasing trend with height, and the proportion of 10 m·s^-1＜ wind speed ≤ 20 m·s^-1 exhibits a fusiform pattern characterized by first increasing and then decreasing with height.The altitude where the largest proportion is located changes as being rising in spring, reaching the highest in summer, decreasing in autumn, and droping the lowest in winter.The proportion of strong winds above 30 m ·s^-1 shows a single increasing trend with height, however, its height, increasing rate, and proportion at each layer are different in different seasons, with the highesty height, and the lowest proportion of each layer in summer, followed by spring and autumn, and with the lowest height, the fastest increasing rate and the largest proportion of each layer in winter.The characteristics of the continental monsoon climate in Jiyuan throughout the year and the northwesterly winds are dominant in the lower layer in January.The dominant wind direction has been varied clockwise from the low layers to the high layers since February.From June to July, the easterly wind occupies, and the deflection height reaches the highest.In August, the dominant wind direction turns counterclockwise from high to low.In November, northwesterly winds are dominant in the entire layer and turn back again, which maintains until January of the following year.

Key words: Sounding data, Upper-layer wind, Wind-field feature, Troposphere