近四十年我国东部盛夏日降水特性变化分析  

Analysis of July-August Daily Precipitation Characteristics Variation in Eastern China during 1958-2000

作　　者：李红梅[1] 周天军[1] 宇如聪[2] 

机构地区：[1]中国科学院大气物理研究所大气科学与地球流体力学数值模拟国家重点实验室 [2]中国气象局中国气象科学研究院灾害天气国家重点实验室,北京100081

出　　处：《大气科学》2008年第2期358-370,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展规划项目2004CB418304;中国科学院创新团队国际合作伙伴计划项目“气候系统模式研发及应用研究”;国家自然科学基金资助项目40625014、40375029

摘　　要：基于中国地区740台站的日降水资料,细致分析了近40年我国东部盛夏即7、8月份降水长期趋势和年代际变化特征。按小雨、中雨、大雨以及暴雨降水强度分类,探讨了不同强度降水在我国东部降水变化中的贡献。结果表明,中国东部地区盛夏降水变化主要受暴雨强度降水变化的影响,占总降水变化60%以上。近40年来,盛夏长江流域降水量、降水频率、极端降水频率以及暴雨降水强度均呈增大趋势,在华北地区则呈减小趋势,除降水频率在长江流域的变化趋势绝对值比华北地区小外,另三个指标在长江流域的趋势变化值大约是后者的2倍。降水强度在中国东部表现出一致的增大趋势,但华北地区增大趋势不显著。华北地区降水的减少主要是小雨强度降水频率减小的结果,强降水的频率和强度在该地区也呈微弱的减小趋势,其中小雨强度降水频率减小趋势大值中心值达到-3%/10a,比中雨以上强度降水频率变化趋势值大一个量级;长江流域降水的增多,是各强度降水频率和强度增大共同作用的结果。长江流域和华北地区在区域平均降水频率、降水强度、极端降水频率、最大降水量的时间序列上,彼此均为负相关关系,其中降水频率和极端降水频率序列在两区域的相关系数通过99%的信度检验。Mann-Kendall检验表明,除华北地区降水强度外,其他降水指标均存在显著的年代际跃变。与1970年代末的气候跃变相对应,华北地区降水频率较之长江流域的跃变明显;但长江流域极端降水在1970年代末的跃变较之华北地区更显著,其降水强度、极端降水频率以及最大降水量均于1970年代末期前后发生显著年代际跃变。Daily precipitation data from 740 stations are used to analyze July-August precipitation trends and decadal variation in eastern China.The precipitation is categorized into four types according to the daily rainfall amount： 0.1-9.9 mm/d,10.0-24.9 mm/d,25.0-49.9 mm/d,and above 50.0 mm/d.Special attention has been devoted to their contribution to the total precipitation variation in eastern China.The results prove that total precipitation variation in eastern China is mainly due to the changes of torrential rain.The trend analyses show that the amount of precipitation,the frequency of precipitation,the frequency of extreme precipitation and the intensity of torrential rain have significantly increased along the Yangtze River valley and evidently decreased in North China during 1958-2000.Except for the frequency of precipitation,trends of other indices along the Yangtze River valley are greater than that in North China.The intensity of precipitation has coherently positive trend in eastern China however is not statistically significant in North China.The drought in North China results from the decrease of the frequency for light rain, with the maximum decreasing trend of -3%/10 a,the frequency and intensity of extreme precipitation in this area also have weak decreasing trends.The flooding along the Yangtze River valley in the past decades results from the increase of all sorts of precipitation frequency and intensity.The variations of precipitation frequency,intensity,extreme precipitation frequency and the maximum precipitation along the Yangtze River valley are out-of-phase with those in North China,as indicated by the significant negative correlations between the regional mean time series.The Mann-Kendall tests show that nearly all precipitation indices except the frequency along the Yangtze River valley and the intensity in North China have significant decadal shifts.In response to the decadal shift of East Asian climate in the late 1970s,the precipitation frequency of North China experienced a shift starting

关 键 词：降水频率 降水强度 极端降水 最大降水量 

分 类 号：P426[天文地球—大气科学及气象学]