How well are the projected responses of the South Asian summer monsoon scaled by climate sensitivity

• 作 者: Xiaolong Chen Tianjun Zhou
• 机 构: LASG,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;University of
• 出 处: 第一届中国大地测量和地球物理学学术大会
• 发表日期: 2014年10期
• 关键词: Equilibrium climate sensitivity South Asian summer monsoon Dynamical sensitivity

　　The equilibrium climate sensitivity (ECS) measures the warming extent of global surface temperature under doubling CO2 concentration.The ECS with large model spread is expected to scale model responses in future projections that are largely subjected to CO2 forcing.The authors evaluate the capability of the ECS to scale the projected responses of the South Asian summer monsoon (SASM) by using Coupled Model Intercomparison Project Phase 5 (CMIP5) models.The ECS can well scale the SASM circulation responses across models but it is not so robust for rainfall.With higher ECS,the weaker Walker circulation and meridional thermal contrast in the tropical upper troposphere decelerate the SASM circulation.However,the dynamic (weaker vertical motion) and thermodynamic (more water vapor) effects on precipitation cancel out substantially.The offsetting loosens the ECS-rainfall correlation.Additionally,the dipole-like warming pattern in the Indian Ocean could counteract the dynamic effect by changing moisture transport.