云南近46年降水与气温变化趋势的特征分析

Characteristic Analysis of Precipitation and Temperature Trend in Yunnan Province in Recent 46 Years

利用云南1961-2007年降水与气温资料进行线性趋势分析和突变检验。结果表明,近46年来云南年均降水量是趋于减少的,其中夏季降水量减少较为明显,减少率为4.5 mm/10a,且夏季降水在1971年前后发生了由多到少的突变。从降水的季节变化特征及异常值统计结果来看,云南雨季平均降水量是趋于减少的,而干季平均降水量趋于增加;从降水的地域分布来看,滇南地区降水呈缓慢减少趋势;滇中降水呈缓慢减少后略升状态;滇西北降水呈略升趋势;滇东北降水为明显下降趋势。近46年云南年平均气温是升高的,从全省气温变化的季节特征及异常值统计结果来看,春夏秋冬四季增温都明显,但冬季气温增加最为显著,增加率为0.27℃/10a,冬季平均气温在1995年出现了一次由冷到暖的突变。滇中及以东地区的气温变化增暖趋势明显,滇西地区气温也为增暖的变化趋势。

Using the latest data of precipitation and temperature in Yunnan in the period from 1961 to 2007, their linear variation and mutations are analyzed. The results indicate that the average annual precipitation in Yunnan in recent 46 years tends to decrease. In particular, the summer precipitation decreases obviously, with a decreasing rate of 4.5 mm/10a. The summer precipitation abruptly decreased around 1971. From the seasonal variation of precipitation and the statistical results of precipitation anomalies, the mean precipitation in rainy seasons in Yunnan tends to decrease, however the average precipitation in dry seasons tends to increase. From the perspective of geographical distribution of precipitation, the precipitation in southern Yunnan shows a gradual decrease trend. But the precipitation in central Yunnan indicates a trend of gradual decrease and then increase. The precipitation in northwest Yunnan tends to slightly increase. In northeast Yunnan, precipitation shows a clear decreasing trend. In recent 46 years, the annual mean temperature in Yunnan is increasing. The characteristics of seasonal temperature variation and the statistical results of temperature anomalies show that the temperatures in all the four seasons obviously increase, especially the winter temperature, which increases the most obviously with an increasing rate of 0. 27℃/10a. A mutation of winter average temperature from cold to warm occurred in 1995. The warming trend in central and eastern Yunnan is clear. The temperature in western Yunnan also tends to get warm.