Abstract:

Based on the daily mean wind speed, the daily mean temperature, the daily maximum and minimum temperature from five meteorological stations in East Xinjiang during 1960 - 2005, the 74 circulation parameters from NCC and NCEP /NCAR reanalysis data, the annual and inter - decadal variation characteristics ofwind speed in East Xinjiangwere analyzed. Results show that the biggest wind speed areaswere in the north and the south of East Xinjiang and the smallestwere in Balikun - Yiwu basin and Hami basin, and the wind speed change in a year in differrent area p resented basically the same trend. The occurring frequencies ofwind speed from 0 to 2. 9 m·s- 1 , from 1. 0 to 1. 9 m·s- 1 and from 3. 0 to 3. 9 m·s- 1 were 22. 04 % , 18. 46 % and 17. 67% , respectively. The variation of wind speed in East Xinjiang was mainly relative to the strong cold air, cold wave and dust storm. The circulation factors such as westerly index, polar vortex area and intensity, EastAsia trough have good correlation with the variation of wind speed.

Key words: speed, inter - decadal variation, circulation

摘要：

用新疆东部5个气象站1960～2005年的大风、气温资料,结合国家气候中心下发的74项环流指数和NCEP /NCAR月平均再分析资料分析了新疆东部风速变化的特征。结果表明: ①新疆东部地面风速分布特点是北部和南部戈壁地区大,巴里坤—伊吾盆地和哈密盆地小。不同地区风速的年内变化及分布特征基本相同; ②1960～2005年年平均风速下降了0. 94 m·s- 1 ,减弱速率> - 0. 2 m·s- 1 /10 a。南部哈密市风速变化最大,变化速率达- 0. 46 m·s- 1 /10 a,伊吾县的年平均风速变化最小,变化速率为- 0. 09 m·s- 1 /10 a。哈密市夏季变化速率最大为- 0. 5 m·s- 1 /10 a , 46 a下降了2. 3 m·s- 1 ,冬季最小,为- 0. 4 m·s- 1 /10 a,下降了1. 8 m·s- 1 ; ③全地区2. 0～2. 9 m·s- 1级的风速出现频率最大,占22. 04 % ,其次是1. 0～1. 9 m·s- 1等级风速,出现频率占18. 46 % , 3. 0～3. 9 m·s- 1级风速出现频率为17. 67 %; ④新疆东部风速变化主要和强冷空气、寒潮、沙尘暴等天气有关。20世纪80年代中期以后侵入新疆东部的强冷空气天气在次数和强度上明显减弱,这与大陆冷性高压和气旋活动趋弱有关,西风指数、极涡面积和强度及东亚大槽等环流因子与风速变化有着很好的相关性,也与城镇化或观测环境的变化等有关。

关键词: 风速, 年代际变化, 环流形势