中文摘要：

中国北方农牧交错带和非洲Sahel地区均处在季风尾间带的干旱向半湿润气候过渡的的地区，两者在近百年的干湿变化上有着近似的变化周期。本文以非洲Sahel西部地区和中国华北农牧交错带为研究区，通过功率谱分析了两个降水序列的变化周期，用相关分析研究两者之间的滞后时间，由此检测非洲干旱对于中国农牧交错带干旱的预警水平。研究发现，两个地区在降水的年际和年代际变化上存在很好的相似性，中国农牧交错带的干旱比非洲干旱的时间位相滞后约15年，这个时间位相差作为预警中国北方农牧交错带的干旱的置信水平为0．01。

英文摘要：

North China agro-pastoral zone and Africa Sahel belt are both controlled by monsoon climate and are very similar in the aspects of the transition from arid deserts to sub-humid savanna or forest grassland, and the modern environments have nearly the same period of variation in the arid and sub-humid changes. This paper took North China agro-pastoral zone and of Sahel belt as the research area, first analyzed the changing cycle of the two precipitation series using the method of power spectrum, then studied the lag time of the two precipitation series by correlation analysis. Based on these, the early warning level of the drought in Africa Sahel belt on China agro-pastoral zone can be tested. Results show that, a high-level of similarity exists in the inter-annual and inter-decadal variations of precipitation in the two areas, and the temporal phase of the droughts in North China agro-pastoral zone lag about 15 years behind that in the Sahel belt. The confidence level of the time phase difference as the early warning of the drought in North China agro-pastoral zone is 0.01.