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

A near-future, 2-K warming climate simulation comprising over 3,000years 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 +4K 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. Plain Language Summary Our study shows the precipitation changes in the near-future around the 2040s, +2-K climate. Even in the +2-K climate, both extreme precipitation and dryness in the extratropics increase significantly. These results urge to plan for adaptation to extreme weather in the near future. The 2-K warming climate simulation was performed with over 3,000years of ensemble member using 60-km global and 20-km regional atmospheric models. A large number of ensemble data elucidated statistically significant increment of the precipitation extremes, moreover the amplifying of the seasonal precipitation range. The data are helpful to investigate the climate in the near-future containing mixed uncertainty both internal variation and effects of future scenario. It would provide valuable information for policy-making, planning of mitigation, and adaptation for extreme weather events, such as flooding or droughts in the near-future climate.