Future Changes in Rainfall Extremes Associated with El Niño Projected by a Global 20-km Mesh Atmospheric Model

Abstract

A global high-resolution atmospheric general circulation model with grid size about 20 km is used to project future changes in rainfall extremes associated with El Niño at the end of the 21st century. In the future climate projections, hypothetical sea surface temperature (SST) is assumed where the interannual variability of SST remains same as in the present climate. The annual maximum 1-day precipitation total (R1d) over the western North Pacific is largely associated with tropical cyclone activity and positively correlated to the Niño3.4 SST anomalies. It is found that climatological mean R1d will only modestly increase in the western North Pacific in the future, but interannual variability of R1d will largely increase compared to the present due to enhanced association with El Niño. This implies an increasing risk of heavier rainfall events by global warming around the western North Pacific countries.