长江下游地区强降水过程的气候分布特征

The Climatic Distribution Characteristics of HeavyPrecipitation Process in the Lower Changjiang River Region

摘要: 长江下游地区的强降水是受季风影响最明显的区域之一，年内四季分明。冬季主要受来自西北利亚的干冷冬季风影响，夏季主要受副热带系统带来的湿热夏季风影响。5~8月是汛期雨季，副热带系统的湿热气团和来自北方的冷气团经常在这里相遇和相互作用而产生降水。6~7月是夏季风盛行期，在遇到西伯利亚下来的强冷空气后就会在这里发生持续性的强烈湍流运动，就会产生持续性强降水过程，也就是典型梅雨过程。在气象界，有关梅雨方面的研究成果较多，可大多是对梅雨过程的具体个例分析研究，很少见到对强降水过程的气候统计特征研究成果。本文统计分析了长江下游地区(上海等12站)在1951~ 2014年期间的逐点5~8月逐日降水量的分布特征，研究和揭示了长江下游地区强降水过程的时空分布异常特点。该成果是在完成上海气候中心承担的行业专项任务中取得的部分成果，本文得到了专项(专项编号：201306065)资助。

Abstract: The lower Changjiang River region, with four distinct seasons, is one of the most obvious areas in-fluenced by monsoon. In winter, it is mainly affected by the dry and cold winter monsoon from Si-beria; in summer, the hot and humid summer monsoon induced by subtropical system plays an important role in this region. The period from May to August is the rainy and flood season, and precipitation usually happens as a result of the meeting and interaction between the hot and humid air mass from subtropical system and the cold air mass from the North. June-July is the period characterised by summer monsoon, when meeting with the strong cold air from Siberia, the per-sistent intensive turbulence motion will be generated, which in turn leads to the continuous heavy precipitation; that is the typical process of plum rains. In the field of meteorology, there are many studies regarding to the plum rains with most of them focusing on specific case studies of the weather processes and the lack of research achievements concerning climatological statistics of the heavy precipitation processes. This paper statistically analysed the distribution characteristics of daily precipitation point by point during the period from May to August between 1951 and 2014 in the lower Changjiang River region (12 stations, e.g. Shanghai, etc.); the study showed the anomalies of spatial and temporal distribution of the heavy precipitation processes in the lower Changjiang River region. The presented result in this paper is the part of scientific achievements obtained from accomplishing an industry-specialized project undertaken by Shanghai Climate Center and this work is funded by Program 201306065.