关键词: 降水集中期, 统计分析, 汛期降水, 长江下游

Abstract: The precipitation concentration period (PCP) is a new characteristic quantity for attributing the climate of flood season. This new quantity was developed by meteorologists and has shown a better flexibility and objectivity in climatic studies. Analysis of PCP can provide basic and useful information for climatic diagnosing and forecasting in flood seasons. While the current used universal indices of precipitation concentration period (PCP) have shortages in computation and time length definition. Specially, this characteristic quantity has a flaw when it is used in the climate analysis with a longer term, moreover the computational method is too complex to use in routine work. In this paper, a new method of PCP with 15day running mean is developed for the purpose of more effective use of PCP in climate analysis. The authors proved this new method by the use of statistical methods and the synoptic climatological method. Simultaneously, two case studies in the lower Yangtze River and Jinhua area flood season were carried out for the examination of the method. The result indicated that the characteristic quantity of new flood season PCP is time independent with total rainfall in flood season and has remarkable relevance with general trend of precipitation, and it has the stronger ability in describing extreme disaster event in the flood season. Therefore, the new method of PCP with 15day running mean has the explicit weather climate significance. It is convenient, objective and more effective in the practical application.

Key words: precipitation concentration period (PCP), statistical analysis, precipitation of flood season, lower Yangtze River