EOF在广西春季降水分析中的应用

Appliction of EOF Method to Spring Rainfall Forecast in Guangxi

利用EOF方法对广西1961-2003年春季（2-4月）降水进行分析，得出广西降水一致性即旱或涝为春季主要降水类型与桂北-桂南和桂东南-桂西北反位相型。依此广西春季降水可分为桂东北、桂东南和桂西三个区。利用第一时间系数、67个站平均降水距平值和正负距平站数三种方法统计出广西春季历年的旱涝年，1961-2003年期间存在11a涝和14a旱。在降水异常年里桂东南降水变化最大，其次为桂东北，变化最小为桂西。

The spatial and temporal distribution feature of the rainfall anomaly field of spring about Guangxi are analyzed using precipitation anomaly field data of every February to April from 1961 to 2002, and using the method of empirical orthogonal function （EOF）. Following is the result. The first principal component exhibits all over the province is consistent indicating the drought or the flood in spring and the main rainfall models over the north and the south is on the contrary as well as the southeast and the northwest. Precipitation distribution can be divided into three areas such as the northeast, the southeast and the west. Statistical results show that it is drought in 11a and flood in 14a from 1961 to 2003. The southeast precipitation variable gradient is greater than the north variable gradient, the western variable is the smallest in abnormal precipitation years.