江淮梅雨的时空变化特征

Temporal Evolution and Spatial Distribution Characteristics of Meiyu in Changjiang-Huaihe River Valley

利用江淮地区37站1954—2001年48 a梅雨特征量资料,采用谐波分析、EOF和最大熵谱分析等方法讨论了江淮梅雨的时空变化特征。结果表明:江淮梅雨时空分布不均,梅雨特征量存在显著的年际—年代际变化特征,梅雨特征量年代际变化之间存在明显的负相关或正相关关系;梅雨特征量存在显著不同的多时间尺度振荡周期和长期演变趋势且江淮地区雨季也呈不同的年际和年代际变化特征。

On the basis of the Meiyu characteristic variable data at 37 stations in the Changjang-Huaihe River Valley from 1954 to 2001, the temporal evolution and spatial distribution of Meiyu characters are investigated in terms of harmonic analysis, empirical orthogonal function（EOF） and maximum entropy spectrum analysis and so on. Results show that temporal-spatial distributions of Meiyu characteristic variables are not homogeneous in the Changjiang-Huaihe River Valley. There are prominent interannual quasi-three years and interdecadal （ 10 years） variabilities in variations of Meiyu characteristic variables, and there are also positive or negative correlations between those interdecadal variations. The duration, rainfall and rainfall rate of Meiyu are positively/close correlated（ P 〈 0. 001 ） and except the onset date, the end date, rainfall and duration of Meiyu all showed an increasing long-term trend