模糊C均值聚类法在新疆年降水分区中的应用

Fuzzy C-Means Clustering Method for Climatic Regionalization about Precipitation in Xinjiang

利用新疆98个气象站1960—2011年的年降水量资料,采用模糊C均值聚类法,对新疆年降水量进行分区研究;同时利用线性趋势、累积距平、M-K检验、t检验相结合的方法,对新疆年降水量在不同区域上的变化趋势以及突变时间等进行了对比诊断分析,得到了新疆地区年降水量分布的空间特征。结果表明:(1)新疆年降水的分布大致可分为7个区域;(2)根据模糊C均值方法所分区域能够体现出由于地形差异导致的降水分布不均匀的特点,这一结果与其他研究干旱区降水分布差异产生的原因相同。分区结果合理,说明该聚类方法适用于区域气候区划;(3)新疆大部分区域的降水量在20世纪80年代中后期以前偏少,低于多年平均值,自80年代中后期以后才开始偏多;不同区域的降水量依次从70年代初、80年代中后期、90年代初开始增加;整个南疆盆地、阿勒泰地区、准噶尔盆地降水的突变时间较为接近;(4)新疆降水量整体异常表现为降水一致多(或少)、北多南少、西多东少。

Based on the annual data of precipitation from 100 meteorological stations in Xinjiang during 1960-2011,spatial distribution of precipitation for the whole region and sub-regions are studied by means of RPCA （rotated principal component analysis）and fuzzy c-means clustering method. At the same time, by using combined methods of linear trend, cumulative departure, M-K test and t-test,the variation trend of the precipitation in different sub-regions and also the abrupt changes are compared and analyzed to find the spatial characteristics of the annual precipitation in Xinjiang. The result showed as follows.（1）It can be roughly divided into 7 sub-regions according to its precipitation in Xinjiang.（2）The sub-regions divided by fuzzy c-means clustering method reflected the features showed an uneven distribution of precipitation caused by terrain differences, which is the same as the results gained by other methods. The reasonable result achieved by this way showed that the fuzzy c-means clustering method can be applied to climatic regionalization.（3） Comparatively speaking,the precipitation in most parts of Xinjiang were less than normal before middle or late 1980s,but more than normal since late 1980s. The precipitation in different sub-regions increased from early 1970s middle or late 1980s, early 1990s, respectively. The abrupt changes of precipitation of the whole Southern Xinjiang Basin, Altay Region and Jungger Basin almost took place in the same time.（4）The whole abnormal structures of precipitation appeared in a way of being dry or wet in the whole Xinjiang,or wet only in the North Xinjiang and dry only in the South Xinjiang,or wet in the western part and dry in the eastern part of Xinjiang.