湖北省夏季降水日变化特征  

Characteristics of summer precipitation diurnal variations in Hubei Province

作　　者：林春泽[1] 刘琳[1,2] 林文才 白永清[1] 祁海霞[2] 杨浩[1] 

机构地区：[1]中国气象局武汉暴雨研究所暴雨监测预警湖北省重点实验室,湖北武汉430205 [2]武汉中心气象台,湖北武汉430074 [3]广水市气象局,湖北广水432700

出　　处：《大气科学学报》2016年第4期490-500,共11页Transactions of Atmospheric Sciences

基　　金：国家重点基础研究发展计划(973计划)项目(2012CB417204);国家自然科学基金资助项目(41375057;41375041;51379149);武汉暴雨研究所2016年基本科研业务费项目

摘　　要：利用2001—2014年湖北省77个气象观测站的整点逐时降水数据,通过划分不同区域和三种量级降水的方法,分析了夏季（6—8月）降水日变化特征。结果表明：1）湖北省夏季降水日变化特征非常明显,降水量曲线呈双峰结构,峰值出现在08时和17时（北京时间,下同）,降水频次与降水强度均呈现“一主一次”的双峰结构,这主要与青藏高原东移来的天气系统自西向东的滞后性以及局地热力强迫有关,发生在傍晚（15—18时）的降水强度有明显的年际增强趋势。2）湖北省降水日变化特征区域差异显著,鄂西北与鄂西南降水峰值主要出现在傍晚和夜间,谷值出现在正午,鄂东三个区域的降水峰值出现在上午和傍晚,谷值出现在午夜。3）近14 a强度为0~20 mm/h的降水呈现减少趋势,主要发生在鄂西地区。其日变化曲线为“一主一次”的双峰结构,主（次）峰值出现在07（17）时。与之相反,短时强降水（≥20 mm/h）的发生概率东部大于西部,平原大于山区,有增加趋势的站点占总站点数的53.24%,峰（谷）值出现在17（12）时。短时特大强降水（≥50 mm/h）峰值出现在15—20时,03—14时出现概率较低。Diurnal variations of precipitation are caused jointly by different thermal and dynamic forcings on the surface.The mechanisms and characteristics involved are extraordinarily complex.This paper, based on hourly raingauge data from 77 stations in Hubei Province, for the period 2001-2014,provided by Hubei Meteorological Information and Technical Support Center, analyzes the diurnal variation characteristics of precipitation in summer （June-August） in Hubei Province by dividingit into five different regions （Northwest Hubei,Southeast Hubei, Jianghan Plain, Northeast Hubei and Southeast Hubei）, and dividing the precipitation into three levels （0-20 mmh-1, ≥20 mmh-1,and ≥50 mmh-1）. The diurnal variation characteristics of summer precipitation in Hubei Province are highly remarkable.The diurnal variation curve of precipitation is of double-peak structure, showing characteristics of semi-diurnal circulation.The peaks of precipitation occur at 0800 and 1700 BST,respectively,and the precipitation levels in the two time periods are the same.The valley values occur at 1200 and 2300 B ST.The diurnal variation curves of both precipitation frequency and intensity are of double-peak structure, with one weaker than the other. This is mainly related to eastward-moving weather systems from the Tibetan Plateau and the effects of local thermal forcing.The precipitation intensity during 1500-1800 BST shows an obvious interannual increasingtrend for the past 14 years. Regionally, the diurnal variation characteristics of precipitation in Hubei Province are noticeably distinct, with the precipitation peak or valley values in different regions occurring at different times.The primary or secondary peak of precipitation amount occurs in the evening or at midnight in Northwest Hubei ; however, whilst this is also the case in Southwest Hubei, the peak amount is not subdivided into a primary or secondary value.Also, the valley values of precipitation in both areas occur at midday.Meanwhile, the primary or secondary peak of p

关 键 词：降水日变化 区域差异 短时强降水 

分 类 号：P426.6[天文地球—大气科学及气象学]