华南前汛期降水异常的时空变化特征

Spatial and Temporal Variations in Pre-Summer Flood Period Precipitation of South China

利用国家气候中心整编的1951—2000年中国160个站的月降水资料,选出华南地区16个代表站。重点分析了华南前汛期降水的年际、年代际变化的时空特征。结果表明:华南地区的降水主要集中在前汛期,而且降水偏多现象易发生在华南东部地区,降水偏少现象易发生在华南北部地区;20世纪50年代前期、60年代中期到80年代初为相对多雨期,而1950年代中期到1960年代中期及1980年代前期到90年代初为相对少雨期,90年代为波动期,但华南前汛期近50年的降水变化的总趋势不明显。华南前汛期降水具有明显的周期性。年际变化的主周期有三个:3,5和7年,年代际变化的主周期为14年。华南前汛期多雨年同期,淮河及黄河下游等地区少雨;而华南前汛期少雨年同期,大致相反。

Using the monthly precipitation data at 160 stations in China during the period of 1951m 2000, 16 stations are selected as representative stations in South China. Based on the analysis of seasonal variation of precipitation in South China, the interannual and interdecadal variations of the precipitation in the pre-summer flood period in South China are emphatically studied in this paper. It is found that： （1） The distribution of precipitation in South China is asymmetrical, the rainfall of the 16 stations are very difference. The most rainfall in the pre-summer flood period and annual are both happen in Heyuan. The least rainfall in the pre-summer flood period and annual are both happen in Baise; （2） There are four positive or negative abnormity centers in the pre-summer flood period in South of China, they are all locate Heyuan, Guilin, Beihai, Yangjiang. The most rain station of positive abnormity frequency center happens in Heyuan. The most station of positive（negative abnormity of precipitation is Heyuan（Guilin））. （3） The total rainfall tendency has change, but not obvious. The flood periods are in the beginning of 1950＇s, in the middle of 1960＇s and the beginning of 1980＇s; the droughts periods are from the middle of 1950＇s to the middle of 1960＇s, and from the middle of 1980＇s to the beginning of 1990＇s; （4） The precipitation anomalies have 3, 5, 7, 14 year periodic variations in the pre-summer flood period in South China; （5） The precipitation in the pre-flood period in South China is opposed to that of most areas of China.