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《Acta Geographica Sinica》 2007-09
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Temporo-spatial Distribution of Summer Precipitationover Qinghai-Tibet Plateau during the Last 44 Years

LU Heli1,2,SHAO Quanqin1,LIU Jiyuan1,WANG Junbang1,CHEN Zhuoqi1,2(1. Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China;2. Graduate School of the Chinese Academy of Sciences,Beijing 100039,China)  
The summer day-by-day precipitation data of 97 meteorological sites on the Qinghai-Tibet Plateau from 1961 to 2004 were selected to analyse the temporo-spatial distribution using accumulated variance,correlation analysis,regression analysis,empirical orthogonal function,power spectrum function and spatial analysis tools of GIS. The result showed that summer precipitation occupied a relatively high proportion in the area with less annual precipitation on the Qinghai-Tibet Plateau and the correlation between summer precipitation and annual precipitation was strong. The altitude of these stations or points and summer precipitation slope presented stronger positive correlation below 2000 m,with correlation value up to 0.604 and significance of 0.01. Summer precipitation slopes disparity between the periods 1961-1983 and 1984-2004 at five altitude scopes (2000-2500 m,2500-3000 m,3500-4000 m,4000-4500 m and above 4500 m) were above zero and accounted for 71.4% of the total. Using empirical orthogonal function,summer precipitation could be roughly divided into three precipitation pattern fields: the southeast Plateau pattern field,the northeast Plateau pattern field and the Three Rivers' Headstream Regions pattern field. The former two presented a reverse spatial distribution value from the north to the south and the reversal line is along 35oN. The potential cycles of the three pattern fields were 5.33a,21.33a and 2.17a respectively,tested by the confidence probability of 90%.
【Fund】: 中国科学院西部行动计划项目“三江源区生态—生产功能区的区划及其评估研究”(KZCX2-XB2-06-03)~~
【CateGory Index】: P468.024;P426.6
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