资源环境科技发展态势分析平台

Climate model simulations have suggested that, in East Asia, the mean precipitation increases with global warming, leading to more humid conditions. In contrast, Cretaceous proxy data show an aridification in the low latitudes of East Asia during the mid-Cretaceous when CO₂ levels were higher and the climate was relatively warmer compared to the early and late Cretaceous. We conducted simulations of the Present-day and Cretaceous climates with different CO₂ levels using an atmosphere-ocean general circulation model, MIROC4m, to investigate the hydrological cycle changes as CO₂ is increased. The results show that the responses of the hydrological cycle in East Asia for the Present-day and Cretaceous experiments are the exact opposite; an increase in the Present-day, and a decrease in the Cretaceous, as geological evidence shows. Overall, the opposite response in the Cretaceous is attributed to a weaker summer atmospheric circulation, associated with the absence of the Tibetan Plateau.