过去2000年来青藏高原气温变化及对人类活动的影响

The Temperature Change and its Influence for Human Movement of the Tibet Plateau Over the Past 2000 Years

选取24条明确指示气温的树轮、冰芯和沉积物等高分辨率环境记录,提取1981条气温记录,采用单样本订正-多样本平均集成法重建青藏高原过去2000年十年分辨率气温序列.该序列表明过去2000年温暖时段主要发生在0-235AD、775-1275AD和1845-2000AD,冷时段在245-765AD、1045-1145AD和1385-1835AD.小冰期在青藏高原表现明显,最冷时段为1635-1675AD;19世纪气温开始转暖,并在20世纪后期突破过去2000年的极值.过去2000年气温变化对人类社会影响较为显著,245-765AD是过去2000年持续时间最长的冷期,正值魏晋南北朝时期,季风衰弱,季风分界线南移,植被带南移,导致逐水草而居、生活在原季风分界线的鲜卑秃发部和吐谷浑部等南迁,同时历史时期气温变化区域战争、气象灾害等息息相关.

Choosing 24 high resolution environment records that can definitely indicate temperature,such as tree rings,ice cores and sediment,and extracting 1981 temperature records,using converted single sample from local to regional and averaged by multiple samples,10 years of temperature resolution of synthetical sequence of the Tibet plateau over the past 2000 years were estabilished.The sequence showed that the warm stages of the past 2000 years occurred mainly in 0~235AD,775~1275AD and 1845~2000AD,the cold stages occurred in 245~765AD,1045~1145AD and 1385~1835AD.It is coldest stage of the Little Ice Age occurred in 1635~1675AD;The temperature during the 19 th century began to warm,the trend of warming was obvious and break through extrem value of the past 2000 years in the late 20 th century.Temperature variation over the past 2000 years had significant effects on human society,245~765AD was the longest cold period over the past 2000 years,when was just the wei jin northern and southern dynasty,the monsoon was becoming weak,the dividing line of monsoon and vegetation zone were moving southward,which resulted in that Xianbei and Tuyuhun tribe living in the dividing line of monsoon moved southward,meanwhile,the temperature change was closely related with the local warm and meteorological disaster.