Response of Future Summer Marine Heatwaves in the South China Sea to Enhanced Western Pacific Subtropical High

Marine heatwaves (MHWs) are prevalent in the South China Sea (SCS) and are primarily caused by the anomalous western Pacific subtropical high (WPSH) which suppresses the SCS summer monsoon. Our study investigates future summer MHWs in the SCS in response to the enhanced WPSH. The results show that the WPSH will be strengthened in most models under the highest emission scenario. Total days of summer SCS MHWs will significantly increase with the enhancement of the WPSH and peak at the end of the 21st century. The high-value area of total days of summer MHWs (>50 days) appears in the south-central SCS. The intensity of MHWs exhibits little response to the strengthening WPSH. In addition, the weakening of the SCS cold filament due to the anomalous WPSH also favors summer MHWs. Furthermore, increased future severe summer SCS MHWs will create a higher bleaching risk for coral reefs.

Automated summary

This study investigates the future summer marine heatwaves (MHWs) in the South China Sea (SCS) caused by the strengthening of the western Pacific subtropical high (WPSH). The results indicate that under the highest emission scenario, the WPSH will be strengthened, leading to a significant increase in the total days of MHWs in the SCS, particularly in the south-central region. The intensity of MHWs shows little response to the strengthening of the WPSH, but the weakening of the SCS cold filament favors the occurrence of MHWs. Moreover, the increased severe summer MHWs pose a higher risk of coral reef bleaching.