湖南夏季降水日变化特征  

Characteristics of Summer Precipitation Diurnal Variations in Hunan

作　　者：戴泽军[1,2,3] 宇如聪[1,4] 陈昊明[1,2] 

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,北京100029 [2]中国科学院研究生院,北京100049 [3]湖南省气象台,湖南长沙410007 [4]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：《高原气象》2009年第6期1463-1470,共8页Plateau Meteorology

基　　金：国家重点基础研究发展规划项目(2004CB418304);国家自然科学基金项目(40625014);公益性行业专项(GYHY(QX)20076-12);湖南省气象局重点项目(200602)共同资助

摘　　要：利用湖南96个测站13年的逐时自记降水资料,分析了夏季(6～8月)降水日变化特征。结果表明,湖南夏季降水日变化呈现显著的区域差异。湘东南降水量、降水频次峰值主要出现在午后到傍晚,而其它地区的降水峰值一般出现在清晨。进一步分析显示,降水频次峰值出现时次分布更集中,区域特征更鲜明。湘西北、湘东南区域平均的累积降水量、降水频次及降水强度的日变化在清晨和午后均呈双峰型特征。湘西北主(次)峰值出现的时间大致与湘东南次(主)峰值出现的时间对应。同时,降水日变化与降水持续时间密切相关。持续5～10 h降水事件是持续1～4 h事件与持续10 h以上事件降水量峰值出现时间发生显著变化的过渡降水事件。持续1～4 h(10 h以上)的降水事件的极值降水始发时间为午后至傍晚(夜间)。在不同持续时间的降水事件中,持续2 h降水的累积量最大。The characteristics of summer precipitation diurnal variations were analyzed using the hourly station rain-gauge data in Hunan during 1992-2004. The results show that the peak of rainfall mainly occurred between late afternoon and evening in southeastern Hunan Province, but in the other region in the early morning. The spatial distributions of the diurnal phase of the maximum precipitation exhibit similarity to that of the maximum frequency, while the occurred time of the former is more centralized, and the regional characteristics of the former is more distinctive. Diurnal variations of the averaged precipitation amount, frequency and intensity over the whole Hunan and southeastern Hunan Province present typical double-peaks, while the diurnal variations over northwestern Hunan Province only have single-peak. The diurnal rainfall is correlated to the rainfall duration, and there exist distinctive difference between southeastern Hunan and northwestern Hunan Province on the rainfall diurnal characteristics. The rainfall amount associated with the 2 h duration rainfall events exhibit peak among those for rainfall events with duration from 1 to 24 h. The precipitation amount of the rainfall events over southeastern Hunan Province with duration of 1-6 hours is relatively much more than that over northwestern Hunan Province.

关 键 词：湖南 降水量 日变化 降水持续性 

分 类 号：P426.6[天文地球—大气科学及气象学]