广西地形分布与前汛期降水时空变化关系

Relations between Terrain Distribution and Spatial-temporal Change of Early Flood Season Precipitation in Guangxi

采用广西88个测站1959-2006年4-6月月平均降水资料,运用小波分析、EOF、REOF、新型区域旱涝指数等方法,研究了广西前汛期不同区域降水的长期变化特征。结果表明:(1)广西前汛期降水异常可分为8个地形空间分布型:桂东南、桂东北、桂东、桂西、桂西南、桂西北、桂南及桂中;(2)各异常区代表站降水的时间演变特征、不同年代盛行的主要周期均有所差异,但大部分区都存在2～4 a的短周期和12～14 a的长周期变化;(3)上世纪60年代全区性大涝大旱,70年代除桂西、桂西北外的其它地区平均气候态均以湿润状态为主,而80年代除桂西南、桂南外其它区以干旱状态为主要特征,进入90年代后出现局地敏感气候区。

With the data of mean precipitation from April to June during 1959-2006 in 88 observation stations of Guangxi, the methods of the wavelet analysis, EOF, REOF, new indexes of regional drought and flood, and so on, are used to study the secular variation characteristics of precipitation in early flood season in different regions of Guangxi. The results show that ： （ 1 ） the abnormality of the precipitation in early flood season may be divided into 8 types of terrain distribution in Guangxi, including southeast, northeast, east, west, southwest, northwest, south and central Guangxi; （2） the time evolution characteristic of precipitation for typical stations in abnormal regions and the prevailing periods for different ages are different, a short period of 2 -4 years and a long period of 12 ~ 14 years can be found in most areas; （3） during the 1960s, severe drought and flood disasters occurred in the whole region; during the 1970s, average climate conditions were primarily moist in most areas of Guangxi except the west and northwest; during the 1980s, the conditions were mainly in dry in most areas except the southwest and south; after the1990s, some sensitive climatic zones occurred in part regions in Guangxi.