Precipitation Changes in a Climate With 2-K Surface Warming From Large Ensemble Simulations Using 60-km Global and 20-km Regional Atmospheric Models

Abstract

A near-future, 2-K warming climate simulation comprising over 3,000 years of ensemble simulations was performed using 60-km global and 20-km regional atmospheric models. Even in the +2-K climate, indices of extreme precipitation and dryness increased significantly in the extratropics compared with the historical climate. Mean precipitation increases in the rainy season and decreases in the dry season, indicating that the seasonal precipitation range becomes amplified with global warming. The intensification of precipitation and dryness from +2 to +4 K was also robust in the mean for climatological wet and arid regions. Around Japan, which was classified as a wet region, the regional atmospheric model predicts that the extreme hourly precipitation in the future climate becomes more extreme on hot days, but slightly weaker on cold days. This extreme precipitation has a high sensitivity to air temperature exceeding 7%/K.