The role of sea surface temperature in shaping the characteristics of future convective afternoon rainfall in Taiwan

Abstract

Convective afternoon rainfall (CAR) is a significant summer rainfall feature in Taiwan. This study investigates the projected uncertainties in summer CAR in Taiwan, using a dynamical downscaling approach with the Weather Research and Forecasting Model (WRF) and the High-Resolution Atmospheric Model (HiRAM). The projections were driven by four different sea surface temperature (SST) categories derived from CMIP5 model simulations under the RCP8.5 scenario. All projections indicate a reduced frequency but increased intensity of CAR over Taiwan by the end of the 21st century. However, notable differences in the degree of CAR changes were observed among simulations with varying degrees of Pacific SST warming. These variations in potential future changes in CAR frequency and intensity can be attributed to the variations in daytime thermal instability, local inland wind convergence, and moisture flux convergence over Taiwan. Furthermore, this study explored the linkage between local thermodynamic conditions and projected large-scale circulation patterns.