阿克苏地区雷暴时空变化特征

 利用阿克苏地区1960—2010年雷暴资料,采用气候倾向率、保证率等气候诊断方法,探讨了阿克苏地区雷暴的时空分布规律、气候变化趋势等。结果表明,阿克苏地区雷暴空间分布表现为西多东少、北多南少,位于该地区西部的乌什县为雷暴多发中心;全区年平均雷暴日数为18.7~52.0 d;阿克苏地区每10 a雷暴日数减少2.8 d;雷暴主要集中在3—11月,7月达到最大值,11月下旬至翌年2月基本无雷暴;80%的保证率下雷暴初日出现在5月中旬至下旬之间,雷暴终日出现在9月下旬至10月中旬之间;阿克苏地区一日当中雷暴主要发生在午后至前半夜,雷暴高峰值出现在16—19时,雷暴平均持续时间在35~47 min,雷暴出现最多的方位是W和N。

Spatialtemporal Variations of Thunderstorms in Aksu,Xinjiang,China

The spatial-temporal variations and change trend of thunderstorms happened in Aksu were analyzed by means of climate diagnose methods such as climatic trend rate and guarantee rate,and based on observation data of thunderstorms from 1960 to 2010.Results showed that:(1) The spatial distribution pattern of thunderstorms in Aksu was characterized by rare in south and east but much in north and west,and with the most frequency in the Uchturpan County.(2) The mean annual thunderstorm frequency in Aksu area ranged from 18.7 to 52.0 days.(3) The variation of the annual thunderstorm days in Aksu decreased at the rate of 2.8 days per decade in these 50 years.(4) Thunderstorms mainly occurred from March to November,with peak in July.There were almost no thunderstorms from late November to the next February.(5) Under the guarantee rate of 80%,the initial day of thunderstorms occurred in period from the second pentad to the third pentad of May,and the last date occurred from the third pentad of September to the second pentad of October.(6) Thunderstorms frequently occurred from afternoon to midnight and the peak appeared in 16:00-19:00.The mean duration was 35~47 minutes and the most frequent direction of thunderstorms was north and west.