贵州夏季降水异常的区域特征

利用贵州省19个测站1951～2000年夏季逐月降水资料,计算了降水量的月平均（区域平均）标准化距平。并进行模糊聚类分析、经验正交函数分解（EOF）和小波分析,研究了贵州夏季降水异常的区域特征。结果表明,贵州夏季降水在近50 a中存在5个明显的气候段：20世纪50年代前期为多雨期;50年代中期到60年代前期为少雨期;60年代中后期为多雨期;70～80年代为少雨期;90年代以后进入多雨期;降水呈增多的趋势。全省一致性是贵州夏季降水的最主要特征,同时还存在区域差异。贵州夏季降水异常有5种空间分布型,即：全省旱（涝）型、东旱（涝）西涝（旱）型、南旱（涝）北涝（旱）型、中东旱（涝）西南涝（旱）型和西南旱（涝）其余涝（旱）型。各型降水具有多时间尺度振荡的特点,存在10～12 a、4～5 a、2～3 a的周期。

Regional Characteristics of Summer Precipitation Anomalies in Guizhou

Based on the monthly precipitation data during 1951-2000 from 19 meteorological stations in Guizhou province,the regional characteristics of precipitation anomalies in summer are studied by using methods of the fuzzy assembling analysis,empirical orthogonal function(EOF) analysis and wavelet analysis on normalized anomaly of 19 stations'monthly averaged rainfall.The results show that five obvious rainfall periods occurred in the recent 50 years,including wet in the early 1950s,dry from the middle of the 1950s to the early 1960s,wet from the middle of 1960s to the end of 1960s,dry in the 1970s and 1980s,wet after the 1990s,at the same time,the total rainfall presented increasing trend.The coincident variability occurred in summer rainfall of Guizhou,but some regional difference also existed.The variations of precipitation anomalies in summer can be divided into five spatial patterns,namely dry(wet) in the whole province,dry(wet) in the east and wet(dry) in the west,dry(wet) in the south and wet(dry) in the north,dry(wet) in the middle and east part but wet(dry) in the southwest,dry(wet) in the southwest and wet(dry) in other areas.It presented obvious multiple time scales of 10-12 years,4-5 years and 2-3 years variations for different rainfall patterns.