Dynamic amplification of future extreme precipitation in East Asia in high-resolution climate models

Abstract

Extreme precipitation over East Asia is projected to intensify in the future at a rate greater than that expected from temperature-based scaling. However, substantial uncertainty remains in projections of extreme precipitation at regional scales. Using four high-resolution climate models under the SSP5-8.5 scenario, we quantify extreme precipitation changes over China (CN) and Korea–Japan (KJ) domains and their sensitivity to model resolution. Future projections indicate increases in both intensity and frequency of extreme precipitation, with frequency increases particularly pronounced for more intense events. While projected changes over the CN domain exhibit relatively weak sensitivity to model resolution, a pronounced resolution dependence emerges over the KJ domain: high-resolution simulations project intensification rates (8%–13% from 1991–2010 to 2031–2050) that are 1.2–2.0 times greater than in their low-resolution counterparts, depending on the model. Scaling analysis reveals that thermodynamic changes dominate the precipitation intensification at relatively low resolutions, while dynamic changes are strongly model- and resolution-dependent and explain much of the inter-model spread. Notably, in the two models with the finest resolutions, dynamic contributions become comparable to or exceed the thermodynamic contributions over the CN domain, suggesting that projected extreme precipitation may further intensify at even higher resolutions. Additional diagnostic analysis indicates that changes in the horizontal scale of vertical motion can account for changes in the intensity of ascent in some cases, but not consistently across models and regions.