江西冰雹与雷雨大风气候变化特征的对比分析

Comparison of Climatic Characteristics Between Hailstorm and Intense Gust in Jiangxi Province

利用江西省85个气象站46年的监测资料,采用气候统计分析方法,研究江西省冰雹与雷雨大风气候变化特征,结果表明:冰雹易发区主要分布在江西中西部,有4个中心;雷雨大风易发区主要分布于中北部的地势平整地区,有2个中心。冰雹季节变化呈单峰型,3—5月最容易出现冰雹,4月份最多;雷雨大风季节变化呈双峰型,主要出现在3-8月,3-5月为一高峰,6-8月为另一高峰。冰雹1981年以前以12 a周期经历了3次转换,1981年后以18 a周期进行变化,同时还在9 a时间周期进行了4次转换。雷雨大风主要以中高频周期振荡为主,1973年前为12 a的振荡周期,1974年后,振荡周期主要以6 a为主。EOF展开的第一特征向量表明江西冰雹与雷雨大风的变化趋势总体特征是一致的;第二特征向量表明冰雹和雷雨大风在地势平整地区与多山地区都存在反位相变化,而江西南部雷雨大风变化更显著;第三特征向量表明冰雹和雷雨大风在武夷山附近与其他地区都存在反位相的变化。

Based on the observation data and records at 85 observation stations in Jiangxi Province during 1959—2004,spatial-temporal characteristics of hailstorm and intense gust in Jiangxi are investigated by using multiple statistics.Major results are as follows：Hail often occurs in the central and west parts of the province with four extreme centers,while intense gust occurs in the central and north plains with two centers.In terms of seasonal variations, the temporal distributions of hail is categorized as one-peak type,and is more likely to occur from March to May and most frequent in April.While gust shows a double-peak distribution,indicating the concentration of gust between March and August,with one peak during the period of March to May and the other peak from June to August.From spring to summer in the past 46 years,the abrupt climate change of gust shows that its frequency has decreased in Jiangxi since 1992,while the interdecadal variation of hail has not demonstrated obvious climate abruption.Hail varies by a 12-a scale before 1981 with three periods,while after 1981 it becomes an 18-a cycle and at the same time with 4 periods on a 9-a scale.The middle-to high-frequency variations are dominated for the gust,showing a 12-a scale before 1973 and a 6-a cycle after 1974.The first mode of EOF indicates that the variation trend is consistent for hail and intense gust.According to the second mode of EOF,the spatial variation of hail and gust in the plain shows a reverse trend in relation to mountainous areas,especially gust in the south Jiangxi.