Projection of the summer northern East Asian low under global warming in CMIP5 models

Abstract

The East Asian summer climate is modulated by a low-pressure system over northern East Asia (NEAL) and a subtropical high over the western North Pacific. Many studies have focused on the subtropical high, but little is known about NEAL, especially its change in the future under global warming scenarios. This study investigates the projected change in NEAL in the late twenty-first century, using the outputs of 20 models from Phase 5 of the Coupled Model Intercomparison Project — specifically, their historical climate simulations (HIST) and future climate projections under the Representative Concentration Pathway 4.5 (RCP4.5) and 8.5 (RCP8.5) scenarios. The results show that the models capture the NEAL well in HIST. The NEAL is weakened in the late twenty-first century under the two RCP scenarios, with a stronger weakening under RCP8.5 than under RCP4.5. The weakened NEAL increases the geopotential height zonal gradient in the west and causes a southerly anomaly, which may bring more moisture and rainfall to northern East Asia.

Keywords

• Northern East Asian low
• East Asian summer monsoon
• global warming
• CMIP5
• projection