Dynamical downscaling of climate change by using RCMs: Preliminary results

Abstract

Dynamical downscaling of climate change with regional climate models has provided detailed information required for mitigation and adaptation of climate change on local or regional scales. However, most of ocean downscaling experiments hasbeen done by oceanonly regional models which exclude proper air-sea interactions. In this study, to project future changes in Korean waters, we have developed a regional atmosphere-ocean coupled climate model (RCCM) for the Northwest Pacific Ocean, based on the COAWST (Coupled-OceanAtmosphere-Wave-Sediment Transport coupled model) originally developed by USGS (US Geogological Survey). The RCCM consists of the Regional Ocean Modeling System (ROMS) as an oceanic component and the Weather Research Forecast (WRF) as an atmospheric component. The ocean model has a horizontal resolution of 1/12 degrees while the atmospheric model, covering the East Asian region, has a horizontal resolution of 50 km. As the initial and lateral boundary conditions, we used future climate changes under Representative Concentration Pathway 4.5 scenario simulated by CanESM2 that well reproduces the East Asian monsoon. The future projection experiments show that the coupledmodel allowing air-sea interaction projects a significantly different surface warming compared with projection with ocean-only model. For example, contrary to the ocean-only model projection showing greater surface warming in winter than ineen done by oceanonly regional models which exclude proper air-sea interactions. In this study, to project future changes in Korean waters, we have developed a regional atmosphere-ocean coupled climate model (RCCM) for the Northwest Pacific Ocean, based on the COAWST (Coupled-OceanAtmosphere-Wave-Sediment Transport coupled model) originally developed by USGS (US Geogological Survey). The RCCM consists of the Regional Ocean Modeling System (ROMS) as an oceanic component and the Weather Research Forecast (WRF) as an atmospheric component. The ocean model has a horizontal resolution of 1/12 degrees while the atmospheric model, covering the East Asian region, has a horizontal resolution of 50 km. As the initial and lateral boundary conditions, we used future climate changes under Representative Concentration Pathway 4.5 scenario simulated by CanESM2 that well reproduces the East Asian monsoon. The future projection experiments show that the coupledmodel allowing air-sea interaction projects a significantly different surface warming compared with projection with ocean-only model. For example, contrary to the ocean-only model projection showing greater surface warming in winter than in