Seminar

Understanding the Holocene climate mystery is crucial for projecting future climate in an anthropogenic era. Yet the Holocene hydrological and temperature conditions in mid-latitude Asia, a climatically sensitive region dominated by monsoonal and westerlies circulation, remain controversial. In this talk, I will present biomarker and isotopic records from mid-latitude Asian lakes to infer Holocene climatic changes and associated mechanisms. Results suggest that the n-alkane P_aq index and isotopic compositions of total organic carbon could be used as lake-level indicators in mid-latitude Asia, and isotopic differences between lake water and terrestrial water largely reflect aridity changes in arid Central Asia since the mid-Holocene. Meanwhile, substantial meltwater input to mid-latitude Asian lakes over the deglaciation and early Holocene should be considered when inferring Asian summer monsoon and westerlies behavior, and the spatial variability of Holocene temperature evolution over mid-high latitude Eurasia appears to be associated with the wavy pattern of westerlies during the early to mid-Holocene. Moreover, northwestward migration of the monsoonal limit during the Medieval Warm Period has been identified, possibly associated with strengthened summer monsoon. Findings in this study provide insight into Holocene climatic reconstructions and model simulations.

Additional information: Ms. JIANG Jiawei, jwjiang@connect.hku.hk