a. Dynamical downscaling method
A high-resolution version of the Max Planck Institute Earth System Model (MPI-ESM), MPI-ESM-1-2-HR, which corresponds to a 1.0° × 1.0° grid spacing and has an output interval of 6-hour, was used to set the initial and lateral boundary conditions to perform dynamical downscaling over the PRD due to its good representation of large-scale forcing and high spatial resolution. The model’s horizontal resolution of 100 km for the atmospheric component and 40 km for the ocean component rank high among CMIP6 models and can provide more accurate initial and boundary conditions for the regional model and better capture small-scale physical processes (Adachi and Tomita 2020). In the evaluation of the multi-models in CMIP5, MPI-ESM-MR, the antecedent version of MPI-ESM-1-2-HR, outperformed the other models in simulating the East Asian monsoon regions (Camargo 2013). MPI-ESM-1-2-HR in CMIP6 has higher resolution and complexity than its lower-resolution versions and has shown to have a well-balanced radiation budget and a better performance in atmospheric dynamic, such as mid-latitude storm track dynamics and atmospheric blocking (Müller et al. 2018; Xu et al. 2021; Han et al. 2022). Moreover, MPI-ESM-1-2-HR can effectively reproduce the temperature signals of the 20th century and has projected that the global warming level from 1850 to 2080–2100 will range from 1.5 °C in RCP2.6 to 4.4 °C in RCP8.5. The Weather Research and Forecasting (WRF) model was used as a nested regional model, driven by MPI-ESM-1-2-HR, to generate fine-resolution regional climate information pertaining to the PRD.