中文摘要：

利用青藏高原地区68个测站1973～2007年近35a的日照时数资料,采用主成分分析、旋转主成分分析、小波分析等方法对年日照时数变化的时空特征进行了分析。结果表明：1.青藏高原年日照时数呈现东南部较少,逐渐向西北地区增加的特征,近35a青藏高原西部、西藏西南部和青海西南部年日照时数呈增加趋势,其余地区以减少趋势为主。第一载荷向量场反映了全区日照时数较一致的偏多或偏少;第二三载荷向量场分别反映了高原日照时数南北相反变化以及中部与西部、北部相反变化的差异。2.青藏高原年日照时数空间异常区可分为7个,即高原东南区、高原北部区、高原中部区、藏东区、青海北部区、藏西南区和高原西部区。高原北部和中东部年日照时数减少趋势较为显著,高原西部和西南部年日照时数呈增加趋势。3.高原东南区、高原中部区、青海北部区和藏西南区存在显著的16a周期,其他异常区的显著周期及其年代变化差异较大。

英文摘要：

On basis of the monthly sunshine duration data for the period 1973-2007 collected from 68 observational stations over Qinghai-Tibet,the methods of principal component analysis,rotated principal component analysis,and wavelet analysis are used to analyze the spatial and temporal characteristics of annual sunshine duration over Qinghai-Tibet.The results of our research may lead to the following conclusions：（1）The condition of annual sunshine duration over eastern and southern arid of Qinghai-Tibet was in a good state but poor in western and northern arid.The annual sunshine duration increased in western and southwestern over Qinghai-Tibet in recent 35 years and decreased over other areas.The first loading vector field display the consistent more or less of annual sunshine duration over entire Qinghai-Tibet;the second loading vector field reflect the annual sunshine duration in northern Qinghai-Tibet are opposite with southern Qinghai-Tibet,vice versa;the third loading vector field reflect the annual sunshine duration in middle Qinghai-Tibet are opposite with western and northern Qinghai-Tibet,respectively.（2）The annual sunshine duration abnormal area can be divided into seven subregions：southeastern Qinghai-Tibet,northern Qinghai-Tibet,mid Qinghai-Tibet,eastern Tibetan,northern Qinghai,southwestern Tibetan and western Qinghai-Tibet.The annual sunshine duration decreased remarkable in northern Qinghai-Tibet and mid Qinghai-Tibet and eastern Qinghai-Tibet and increased in western and southwestern Qinghai-Tibet.（3）Southeastern Qinghai-Tibet,mid Qinghai-Tibet,northern Qinghai and southwestern Tibetan appeared the remarkable period of 16 years periodic oscillations,the main periodic and annual change laws of other regions are different from each other.