Changes of local tropical cyclone activity over the South China Sea under global warming in high-resolution atmospheric model projections

Tropical cyclones (TCs) forming over the South China Sea (SCS) are hard to predict as they often make landfall shortly after their formation, resulting in a severe loss of properties and human lives to the adjacent countries. As climate change continues to pose a threat to our planet, it is of importance to understand how TCs forming over the SCS might change under global warming. In this study, we examine the potential changes of local TC activity over the SCS based on HiRAM (high-resolution atmospheric model) simulations and projections at 0.23 × 0.23° horizontal resolution with the representative concentration pathway (RCP) 8.5 scenario. The SCS TC activity, including genesis number and passage frequency, is projected to decrease significantly (about 59%) in the late 21st century period (2075–2099) compared to the present-day period (1980–2004). Analysing the genesis potential index (GPI) clearly indicates that the suppression of SCS TC activity comes mainly from the decrease in low-level vorticity over the SCS. From a large-scale circulation view, the decrease in low-level vorticity can be linked to the weakened monsoon gyre along with the southwestward retreat of monsoon trough under global warming.