Projections of the East Asian Winter Monsoon under the IPCC AR5 Scenarios Using a Coupled Model: IAP-FGOALS

Responses of the East Asian winter monsoon (EAWM) in future projections were studied based on two core future projections of CMIP5 in coordinated experiments with the IAP-coupled model FGOALS2-s. The projected changes of EAWM in climatology, seasonality, and interannual variability are reported here; the projections indicated strong warming in winter season. Warming increased with latitude, ranging from 1oC to 3oC in the Representative Concentration Pathways simulation RCP4.5 projection (an experiment that results in additional radiative forcing of ～4.5 W m-2 in 2100) and from 4oC to 9oC in the RCP8.5 projection (an experiment that results in additional radiative forcing of ～8.5 W m-2 in 2100). The northerly wind along the East Asian coastal region became stronger in both scenarios, indicating a stronger EAWM. Accordingly, interannual variability (described by the standard deviation of temperature) increased around the South China Sea and lower latitudes and decreased over eastern China, especially in North China. The two EAWM basic modes, defined by the temperature EOF analysis over East Asia, were associated with the Arctic Oscillation (AO) and stratospheric polar vortex. The future projections revealed more total variance attributable to the secondary mode, suggesting additional influences from the stratosphere. The correlation between AO and the leading mode decreased, while the correlation between AO and the secondary mode increased, implying increased complexity regarding the predictability of EAWM interannual variations in future projections.