title: Responses of the summer Asian-Pacific zonal thermal contrast and the associated evolution of atmospheric circulation to transient orbital changes during the Holocene.
abstract: This study investigates the response of large-scale atmospheric circulation over the Asian-Pacific sector and precipitation over eastern China to transient orbital changes during the Holocene summer using an intermediate-complexity climate model. Corresponding to variations in the incoming solar radiation, the eddy sea level pressure (SLP) exhibited an out-of-phase relationship between the North Pacific and the Eurasian landmass that was similar to the present-day Asia-Pacific Oscillation (APO) pattern and was defined as the paleo-APO. Its index presented an increasing trend, which implies the enhancement of a zonal thermal contrast between Asia and the North Pacific. Associated with the strengthening of the paleo-APO was the westward shift in North Pacific high pressure. Accordingly, there was less/more summer precipitation over both the middle reach of the Yangtze River and Southwest China/over North China. The high-resolution stalagmite δ18O records further support this decrease in the model precipitation. Along with the strengthening of paleo-APO from the early Holocene to the present, the eddy SLP anomalies exhibited a decreasing/increasing trend over the Eurasian landmass/the North Pacific, with a phase change of approximately 4.5 ka BP, and they both moved westward. Meanwhile, a less rainfall belt over eastern China exhibited northward propagation from southern China.
authors: State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China.|Institute of Climate Systems, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
authors: Dong
authors: D
authors: Xiao
authors: State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China.|Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
authors: Ping
authors: P
authors: Zhao
authors: State Key Laboratory of Marine Geology, Tongji University, Shanghai, 200092, China.
authors: Yue
authors: Y
authors: Wang
authors: State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
authors: Xiuji
authors: X
authors: Zhou