全球变暖背景下江淮地区降水强度分布结构变化的特征分析

利用1961～2006年江淮地区80个站点的逐日降水资料,根据百分位数确定极端降水阈值的方法,比较了全球气候变暖背景下该区域降水强度的分布结构特征。结果表明,在全球气候典型暖异常的年份里,江淮地区极端降水日数占总降水日数的比重比冷年增加30%以上,极端降水总量的比重增加13%左右;而微量降水日数所占比重比冷年减少近60%,微量降水总量减少了80%,说明全球变暖后江淮地区降水强度分布结构呈现弱降水减少,强降水增多的显著两极分化特征,且该特征在江淮地区基本一致。冬、夏季对比表明,冬季的变化幅度比全年和夏季更大。可见全球变暖背景下未来江淮地区降水强度分布结构出现两极分化趋势可能性增加。

Analysis of the Change in the Precipitation Intensity Distribution in the Yangze-Huaihe River Basin under Global Warming

On the basis of the percentiles of different precipitation intensities, daily precipitation data from 80 stations taken during 1961-2006 are used to analyze the distribution characteristics of different precipitation intensities in the Yangze-Huaihe River basin under global warming. The results show that the proportion of heavy rain days in the total precipitation days in the Yangze-Huaihe River basin in the five warmest years according to global temperature is 30% more than that in the five coldest years. However, light rain reflects the opposite characteristics: The proportion in the warm years is nearly 60% less than in the cold years. The trends are the same in the proportions of heavy rain and light rain in the total precipitation amounts; the relative differences are about 13% and 80%, respectively. The distribution of precipitation intensities tends toward "the rich get richer, and the poor get poorer" under global warming. In addition, the difference in winter is greater than that in summer. The precipitation intensity distribution over the Yangze-Huaihe River basin tends to be polarized in the future under global warming.