中国近代北方极端干湿事件的演变规律

The Extreme Dry/Wet Events in Northern China During Recent 100 Years

利用中国1951～2000年的月降水和月平均气温构造了一个适合于研究我国北方地区地表干湿状况的地表湿润指数,以此为基础对我国北方地区极端干旱的分布特征进行深入的研究。结果指出:在东北和华北地区,近10年极端干旱频率显著增加,是近百年少有的大范围高强度的极端干旱频发期,而这些地区极端湿润发生的频率相对减少。和温度变化趋势比较发现,极端干旱的频发区往往对应增温明显的地区。

Using monthly precipitation and monthly mean temperature, a surface humid index was suggested. According to the index, the distribution characteristics of extreme dryness has been deeply analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of North China and Northeast China in the last 10 years, which is a high frequent period of extreme dryness; and a low frequent period in the regions during the last 100 years. To compare with variation trend of the temperature in these regions, the high frequent extreme dryness region is consistent with the warming trend in the same region.