Climate Change Projection over Southeast Asia Based on the Regional Climate Model Simulation

We investigated the future climate change over a coordinated regional climate downscaling experiment (CORDEX) in the Southeast Asia region using a regional climate model (RegCM4) in this study. The model is driven by the global model of MPI-ESM-MR (hereinafter referred to as MPI) at a grid spacing of 25 km under the middle range representative concentration pathway of RCP4.5 with the time period of 1981–2099. Results show that MPI and RegCM4 could reproduce the spatial pattern and magnitude of annual mean temperature and precipitation well over the region. Compared to driving MPI, RegCM4 can provide finer spatial details of the climate variables due to its much higher resolution than MPI; however, it has a prevailing cold bias for temperature and wet bias for precipitation during the simulations. The projected future changes using MPI and RegCM4 show an increase in the annual mean temperature. Moreover, the regional average warming toward the end of the 21st century (2081–2099) is predicted to be 1.8°C and 1.7°C using MPI and RegCM4, respectively. Meanwhile large differences are observed in their precipitation projections, more significant over the Maritime Continent compared to other regions. The precipitation projected using MPI shows an increase, whereas that using RegCM4 model show a considerable decrease. By the end of the 21st century, the projected changes in the regional mean precipitation over Southeast Asia using MPI and RegCM4 are 5% (90 mm) and −6% (−147 mm), respectively. An analysis of the extreme indices simulated with the RegCM4 shows a large frequency of heat waves in the future. The projected increases in precipitation intensity and consecutive dry days over the Maritime Continent indicate high risks of flood and drought over the region.