【摘要】 利用我国北方 12个测站 195 1— 1999年 4— 9月的降水量资料 ,用Z指数变换计算旱涝等级 ,据此讨论北方地区 (35°～ 4 1°N)近 5 0a旱涝的时空变化 .结果表明 ,大体以 90°E和 10 5°E为界可将北方分 3个区域 .东部地区近 5 0a来干旱化趋势比较明显 ,特别在 2 0世纪 80年代中期以来 ,干旱次数异常增多 ;而西部则相反 ;中部呈现过渡特征 .我国北方地区旱涝的时空变化存在从西部向中部、东部逐渐转移的特点 ,每一阶段的旱 (涝 )从西部地区转移到东部地区大约需要十几年 .据此推测北方东部地区在 2 1世纪的头 10a将会出现偏涝的气候特点 .更多还原

【Abstract】 Based on the monthly precipitation data of 12 stations in northern China between April and September from 1951 to 1999, the grades for flood and drought is calculated by Z-index converting, and the temporal and spatial change of drought-flood in northern China(35°～41° N) for the last 50 a is discussesd. The result shows the northern China can be divided in three part by 90° E and 105° E. The drought trend is obvious in the eastern region for the last 50 a, especially, the drought is frequent since the mid of 1980s. But the case is reverse in western region. The mid-region has transitive feature. the temporal and spatial change of drought-flood in northern China for the last 50 a has the characteristic of transferring gradually from west to mid and east. The time transferring from west to east is about more than 10 a. Based on the feature, we can infer it will become more flood in eastern region in 2010s.更多还原