统计了全新世早期气候突变事件'8.2 ka BP冷事件', 并对其触发机制及区域气候响应做了较深入的分析. 从各种气候记录的分布情况来看, 全新世早期的这次冷事件是全球性气候事件, 并非是一种局部气候变冷事件. 全新世早期Agassiz和Ojibway阻塞湖在大约8.47 cal ka BP时突然排泄, 可能是造成8.4～8.0 cal ka BP时期北大西洋地区突然降温的主要原因;另外, 8.4～8.0 cal ka BP期间的太阳辐射量减小或太阳活动减弱, 也可能对全新世早期的这次冷事件有一定强化作用. 由于西风带南移和季风环流减弱等原因的影响, 使得这次冷事件区域气候响应有明显的不同, 欧洲的中高纬度地区、东亚地区呈现一种冷干的气候状态;北美洲三分之二的地区降水量减少、风力加强;中美洲、非洲的大部分地区和阿拉伯半岛均以干旱为主;东欧、地中海地区呈现普遍的冷湿气候环境, 亚马逊盆地、智利玻利维亚高原呈现低湿的气候状况.
High resolutionδ^(18)O and methane records over the last 2ka have been reconstructed from Dasuopu ice core recovered from the Himalayas.Analysis shows that theδ^(18)O record correlates well with the Northern Hemispheric temperature,Dunde ice core record,and with temperature record in eastern China.The warming trend detected inδ^(18)O record from the last century is similar to that during the Medieval warm period.There is a dramatic increasing in methane concentration in the Dasuopu ice core,which reached 1031 nmol?mol-1 in 1997.Moreover,methane concentration in the Dasuopu ice core is about 15%-20%higher than that in Antarctica and Greenland.There is a positive correlation between methane concentration andδ^(18)O in Dasuopu ice core.
YAO TandongL.G.ThompsonDUAN KeqinXU BaiqingWANG NinglianPU JianchenTIAN LideSUN WeizhenKANG ShichangQIN Xiang
