Joint Effects of Coastal and Inland Mountains on East Asian Climate During the Late Cretaceous

Abstract Understanding the climatic impacts of complex mountain configurations is a key challenge, particularly in East Asia during the Late Cretaceous, where diverse mountain landscapes existed but their interactions remain under‐explored. Using the HadCM3L climate model, we simulate climate for various mountain configurations and validate results with two model‐proxy comparison methods based on proxies and paleo‐Köppen classification. Our findings, aligned with geological evidence, suggest the possible presence of the Coastal, Taihang, and Yanshan Mountains during the Late Cretaceous. Surface radiation energy calculations reveal that mountains influenced temperature through cloud processes and caused localized warming due to vegetation changes. Moisture budget calculations show that mountains controlled inland aridity through atmospheric circulation, and contributed to drought near the mountains through transient eddy activity. Coastal mountains dominated climate shifts related to the East Asian monsoon, with the Taihang and Yanshan Mountains amplifying these effects. These insights enhance understanding of paleo‐topography and climate dynamics.