Projected changes of wintertime synoptic‐scale transient eddy activities in the East Asian eddy‐driven jet from CMIP5 experiments

Abstract

The wintertime East Asian eddy‐driven jet (EAEJ) responding to climate change in the 21st century is studied using model outputs from the Coupled Model Intercomparison Project phase 5 (CMIP5). Compared to the location displacement in oceanic eddy‐driven jets, the magnitude change of synoptic‐scale transient eddy activities, measured by eddy kinetic energy (EKE), is a more striking feature in EAEJ. An intensified EKE is projected unanimously by CMIP5 models, suggesting that potential strong winter storm events are likely to happen in East Asian midlatitude in a warming climate. The future change of EKE in EAEJ can be understood in terms of growing baroclinicity wave. The upper level EKE is highly correlated to the low‐level static stability, Brunt‐Väisälä frequency (BVF). CMIP5 models generally project an intensified upper evel EKE with a reduced low‐level BVF (ΔEKE ∝ −ΔBVF). Meanwhile, the enhancement of EKE is also constrained by its historical state (ΔEKE ∝ −EKE). Intermodel variabilities among CMIP5 models reveal a similar but weaker relationship between ΔBVF (or EKE) and ΔEKE, indicating relatively large model diversities and independencies among CMIP5 models.Key PointsThe East Asian eddy‐driven jet will be intensified in a warming climateThe enhancement is related to the surface stability and the historical stateCMIP5 models exhibit large model diversities and independencies