Influence of Northwest Pacific Sea Surface Temperature on the South China Sea Winter Monsoon Based on Multimodel Projections

Abstract

The South China Sea Winter Monsoon (SCSWM) plays a critical role in the regional climate and atmospheric circulation patterns. This study explores the long-term change in the SCSWM from 1979 to 2023, focusing on its connection to the inhomogeneous warming trends of the Northwest Pacific Sea Surface Temperature (NWP-SST). Using NOAA ERSSTv5 and ERA5 reanalysis data, we uncover a strong relationship between the anomalous northeasterly winds, especially the zonal component, in the South China Sea (SCS) and the NWP-SST during boreal winter. Singular value decomposition (SVD) reveals that the NWP-SST is experiencing substantial warming, which could modulate the SCSWM. Evaluating several CMIP6 models, we demonstrate their ability to simulate this relationship reasonably. Future projections under shared socioeconomic pathways (SSP) 126, 245 and 585 indicate that NWP-SST inhomogeneous warming and the corresponding change in the monsoon will continue, especially under high-emission scenarios (SSP585). This study highlights the possible influence of ocean warming on the SCSWM, with potential far-reaching effects on the region's climate patterns.