Younger Dryas时期东亚季风气候和中国东部沙区沙漠变化

位于沙漠／黄土过渡带的杨桃峁剖面，高分辨率地记录了ＹｏｕｎｇｅｒＤｒｙａｓ时期东亚季风气候和沙漠变化历史。在ＡＭＳ１４Ｃ测年基础上，磁化率、粒度和有机质含量等替代性气候指标的测试结果分析表明，ＹｏｕｎｇｅｒＤｒｙａｓ时期东亚季风气候在全球气候变化的影响下，总的表现为与北半球高纬度地区相同的干寒特征，即沙漠总的具有扩大的趋势；但又与南北半球大气相互作用，特别是赤道太平洋地区气压异常引起亚洲季风气候的不稳定有关，表现出降水变化特点，沙漠出现逆过程变化，存在短暂成壤固定时期。

MONSOON CLIMATE IN EAST ASIA AND DESERT CHANGE IN EASTERN CHINA DURING YOUNGER DRYAS PERIOD

The Yangtaomao profile located on the Desert/Loess transition zone has well recorded the history of East Asia monsoon and desert change during Younger Dryas. Several substantial climatic indicators have been tested and analysed based on AMS 14 C dating. The results show that the East Asia monsoon climate during Younger Dryas period was cold dry in general and desert extented correspondingly; but the climate changed with warm wet intervals and desert evoluted with short soil forming processes. The model of climate change and desert evolution was somewhat due to the interaction of atmosphere from Northern Hemisphere and Southern Hemisphere, especially the anomalous air pressure in tropical Pacific region.