Revisiting East Asian monsoon change during the Last Glacial Maximum using PMIP4 simulations

Abstract

The Last Glacial Maximum (LGM; 21 000 years ago) East Asian monsoon was revisited using all available simulations performed by the latest generation of climate models participating in phase 4 of the Paleoclimate Modelling Intercomparison Project (PMIP4). With respect to the preindustrial period, all five models consistently showed a weakening of the East Asian monsoon by 1%–18% in winter and by 2%–32% in summer during that glacial period. Regionally, the LGM monsoon circulation was dominated by southerly wind anomalies in winter but northerly wind anomalies in summer over East Asia in AWI-ESM-1-1-LR, MIROC-ES2L, and MPI-ESM1-2-LR. In the two versions of CESM2, large regional differences existed in the LGM change in the East Asian monsoon, especially for summer. Such changes in the East Asian monsoon can be explained by the various geographical distributions of surface cooling and sea level pressure difference, mainly due to the large volume of ice sheets and lower atmospheric greenhouse gas concentrations during the LGM. The spread among the models and the uncertainty among the proxy data call for further simulation and reconstruction efforts to comprehend the change in the East Asian monsoon during the glacial period.

摘要

利用PMIP4多模式试验数据, 本文重新检查了末次冰盛期 (距今约21 000年) 东亚季风变化. 结果表明: 相对于工业革命前期, 所有5个模式一致模拟显示末次冰盛期东亚季风减弱, 冬季和夏季减幅分别为1 %–18 %和2–32 %; 不同模式中东亚季风环流变化的空间分布存在差异, 这主要源于该时期大尺度变冷和海平面气压梯度变化的空间分布不同; 由于模式之间的差异和重建记录之间的不确定性, 未来有待开展更多模拟和重建工作以更好地理解冰期东亚季风变化.