Precipitation reconstruction in the Asian monsoon region during the 4.2 ka BP event with paleoclimate data assimilation

作者：Fangmiao Xing, Liang Ning, Zhengyu Liu, Jian Liu, Mi Yan, Weiyi Sun, Qin Wen · 年份：2025 · DOI：10.5194/egusphere-egu25-2040 · 研究领域：Geology and Paleoclimatology Research、Geological and Geophysical Studies、Pleistocene-Era Hominins and Archaeology

The 4.2 ka BP event is a pronounced climate event in the Holocene. Since this climate episode was associated with the collapse of several ancient civilizations in many sites worldwide such as Neolithic cultures in China, Ancient Egypt, and Indus Valley civilizations, it has been widely studied in recent years. However, the spatial distribution of precipitation is still controversial in some regions like eastern China. In this study, we use the offline ensemble Kalman filter (OEnKF) data assimilation (DA) method, combining the high-resolution δ18O from speleothems and iTraCE model data which simulates the water isotope, to reconstruct precipitation δ18O and precipitation in the Asian monsoon region during the 4.2 ka BP event. In our DA reconstruction, the precipitation during the 4.2 ka BP event shows a dry pattern from North China to Southwest China and India, and a wet pattern in the middle and lower Yangtze River.