利用中国1951～2010年652站年降水资料和7种东亚夏季风和1种冬季风指数,通过多项数学统计诊断分析,来研究中国年降水量的时空变化特征及其与东亚夏季风指数的关系.结果表明,这60年间全国总平均年降水量未呈现显著的时间变化趋势,但区域间的差异大.聚类分析可提供较客观的降水分区,据554站无缺测降水资料的聚类结果,将全国分成14个主要降水区,各区之间降水变化的差异显著.由7种夏季风指数与14个区的平均年降水量(1951～2010年)的相关系数可见,其中4种夏季风指数与14个区的年降水量之间没有显著相关,有3种指数只与14区中的2～3个区有显著负相关,它们并不能指示其他区域的或整个中国东部的降水变化.中国东部地区的夏季降水分布与东亚夏季风强度变化关系十分复杂,不能仅由降水的多少来认定夏季风的强弱,更不能用任意单个地点的降水记录来表示整个中国东部的干湿状况和夏季风的强度变化.%Variation of annual precipitation in China is one of the basic problems of climate change research, its relations with the East Asian summer monsoon is the important basis for inference of the ancient East Asian monsoon evolution. Issues of whether precipitation series in a single location can be representative of precipitation change in eastern China,as well as the possibility of using precipitation series in a single location as indices for East Asian summer monsoon, are in need of comprehensive analysis and discussion based on systematically collected meteorological observations and records and a variety of summer monsoon index series. In this paper,the authors use the annual precipitation data from 652 stations over 1951 -2010 in China and 7 East Asian summer monsoon indices and the 1 East Asian winter monsoon index to conduct a number of mathematical and statistical diagnosis and analysis. After discounting the effects of missing records and fewer stations in the earlier part of the period, it was found that during the 60 years of 1951 -2010 there was no significant trend in the national average of annual precipitation curve. However, regional precipitation evolution trends differed: western area precipitation showed a significant increasing trend; over a narrow strip from Sichuan to the Northeast of China a decreasing trend in precipitation was significant; and over the larger area of the Southeast of China most locations displayed no significant trend in precipitation. Cluster analysis can provide more objective classification of precipitation distribution. Based on the cluster analysis of precipitation data from the 554 stations with no missing records during 1961 -2010,14main precipitation regions were identified within China. Precipitation variations differ significantly between the various regions. With the exception of annual precipitation in Xinjiang showing an upward trend,other regions exhibited no apparent trends. Spectral analysis showed that there existed oscillations with the period of 2 -4 years in the average annual precipitation in all 14 regions and the 7 East Asian summer monsoon index series (1961 - 2010). The correlation coefficients between the 7 summer monsoon indices and the average annual precipitation( 1951 -2010 years) of the 14 regions showed that 4 of the summer monsoon indices defined by the sea-land air pressure difference did not have statistically significant correlations with the annual precipitation in the 14 regions. Three indices defined in part or entirely by the subtropical circulation showed significant negative correlation with precipitations in 2 - 3 regions. These summer monsoon indices showed certain predictive power for the annual precipitations over the middle and lower reaches of the Yangtze River and the Northwest regions of China. However, they could not show indication of precipitation variations in other regions or the entire eastern region of China. The relationship between the East Asian summer monsoon and the precipitation in China is very complicated. As far as the annual precipitation variation is concerned, the relationship between the East Asian summer monsoon and precipitation in China is mainly reflected in the distribution of the rain belts and spatial distribution patterns of the precipitation. Thus, the intensity of the East Asian summer monsoon cannot be solely determined by the amount of precipitation. Furthermore, precipitation records of a single station cannot be used to indicate the wet and dry conditions over the entire East China and the intensity of the summer monsoon.
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