江浙沪地区55年夏季降水时空分布规律研究

Research on spatial-temporal distribution of summer precipitation in Jiangsu,Zhejiang and Shanghai areas during last 55 Years

为了研究江浙沪地区夏季不同等级降水的时空变化特征，利用94个气象站1958～2012年55a的逐日降水数据，基于MATLAB软件和ArcGIS技术，建立了该地区6～8月多年的大雨、暴雨、大暴雨、特大暴雨发生平均次数空间分布图谱，分析了不同等级降水发生频率的月变化特征；利用小波分析方法揭示夏李不同等级降水的周期性变化规律。结果表明，该地区夏季不同等级降水具有明显的南北分异特征，不同等级的暴雨发生频率南北差异较大；从降水的发生周期来看，几种降水等级在5～20a的时间尺度上周期振荡最为显著，5a以下时间尺度上，夏季降水量少与量多循环交替；预计在2015～2020期间，该地区大雨、暴雨、特大暴雨发生次数增加，而大暴雨发生次数将减少。

Based on the daily precipitation data of 94 weather stations from 1958 to 2012, the MATLAB software, ArcGIS technology and wavelet analysis were used to study the temporal and spatial variation characteristics of summer precipitation in Jiangsu, Zhejiang and Shanghai areas. We analyzed and established the average times of spatial distribution patterns and the av- erage monthly variations of occurrence frequency of different grades of rainstorms from June to August in the area. The periodic laws of different grade rainstorms are analyzed by wavelet - analysis. The results showed that the summer precipitation in the study area is distributed differently from north to south; the occurrence frequency of the rains, rainstorms and heavy rainstorm in the study area is different. According to the occurrence period of precipitation, the various types of rainstorms have the most sig- nificant periodic fluctuation in 5 to 20 years scale. The alternating cycle of less precipitation season and more precipitation season in summer is existed in less 5 year period scale. It is predicted that the probability of rains, rainstorms and extraordinary rain- storm would increase and the heavy rainstorm would decrease from 2015 to 2020.