长江流域30°N沿线昼夜及冬夏降水特征差异分析  

Difference Analysis of Day-Night and Winter-Summer Precipitation Characteristics along 30°N in Yangtze River Basin

作　　者：邓雯[1] 沈铁元[1] 向怡衡 廖移山[1] DENG Wen;SHEN Tieyuan;XIANG Yiheng;LIAO Yishan(Hubei Key Laboratory for Heavy Rain Monitoring and Warning Research,Institute of Heavy Rain,CMA,Wuhan 430205)

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,武汉430205

出　　处：《气象科技》2023年第1期75-84,共10页Meteorological Science and Technology

基　　金：湖北省气象科技发展基金(2021Y03,2022Y26,2022Y06);沙漠气象研究基金(Sqj2011001)共同资助。

摘　　要：利用1996—2020年逐时降水资料,统计分析长江流域30°N沿线不同地形阶梯代表区昼、夜、冬、夏降水的频率、雨量、类条件概率密度等特征,通过研究昼夜比、冬夏比随经度的分布探讨不同高度地形对降水的影响。主要结论如下:(1)30°N沿线四川盆地内降水量和频率的夜昼比向东递减,雅安附近是夜雨强中心区,夜雨现象在四川盆地东侧山地108°E以东趋于消失;盆地内强降水比弱降水更易发生于夜间。(2)30°N沿线冬雨与夏雨存在较大差异,雨量上冬雨小、夏雨大;结构上冬雨弱、夏雨强;降水频次上存在地域差异,第二地形阶梯冬雨少、夏雨多,而第三地形阶梯反之;冬雨受大地形影响更为明显。(3)根据降水第1类类条件概率密度(CCPD1)冬夏比及冬雨CCPD1距平百分比聚类分析,可将8个分区分为3类,该分类与地理位置、地形阶梯有良好的对应关系。(4)夏雨受局地地形影响显著,将夏雨CCPD1距平百分比高于10%的峰(低于-10%的谷)值区定义为夏雨强(弱)潜力区,则各分区强、弱潜力区表现各异。江汉平原南部、鄱阳湖以北发生短时强降水潜力较大,雅安出现极端短时强降水潜力大(强潜力区≥61 mm);冬雨强潜力区(CCPD1距平百分比高于50%的峰值区)位于第三地形阶梯上的Ⅶ、Ⅷ、Ⅸ分区(潜力值1~20 mm),而该降水区间也是雅安和盆地中央的弱潜力区(CCPD1距平百分比低于-50%的谷值区)。Based on the hourly rainfall data,the frequency,rainfall and class-conditional probability density of day and night,winter and summer rainfall in different terrain ladder representative districts along the 30°N are statistically analyzed.The influence of different terrain heights with longitude on rainfall is explored by studying the distribution of day-night and winter-sumer ratios of rainfall.The results show that:(1)Along the 30°N,the rainfall and frequency ratio of night to day decreases eastward in the Sichuan Basin.Ya’an is the high-value centre of strong night rainfall.The phenomenon of night rainfall tends to disappear to the east of 108°E mountain in the east of the Sichuan Basin.Night rainfall is more likely to occur in strong precipitation in the basin than in weak precipitation.(2)There is a big difference between winter and summer rains along the 30°N line.Winter rainfall is small,and summer rainfall is large;structurally,the rain is weak in winter and strong in summer;there are regional differences in frequency.The second topographic step has less winter and more summer rains,while the third topographic step in opposite.Winter rains is more obviously affected by large terrain.(3)According to the cluster analysis of the first kind of Class-Conditional Probability Density 1(CCPD1)ratio of winter to summer and CCPD1 anomaly percentage of winter rains,the eight sub-regions can be divided into three categories,which have a good corresponding relationship with geographical location and terrain steps.(4)Summer rainfall is significantly affected by local terrain.The peak value area of anomaly percentage of the summer rain CCPD1 higher than 10%(or valley of lower than-10%)is defined as the summer rain strong(weak)potential area,and the strong and weak potential areas are different.There is a great potential for short-term heavy precipitation in the south of Jianghan Plain and north of Poyang Lake,and there is a great potential for extreme short-term heavy precipitation in Ya’an(the strong potential a

关 键 词：逐时降水 降水频率 类条件概率密度 夜昼比 冬夏比 30°N沿线 长江流域 

分 类 号：P468.024[天文地球—大气科学及气象学]