Future Change in the Vietnam Upwelling Under a High-Emission Scenario

Abstract

The Vietnam upwelling is a crucial circulation feature in the South China Sea. Although previous studies have shown that various coastal upwellings around the world may intensify under global warming, future changes in the Vietnam upwelling remain unclear. To address this knowledge gap, we analyzed the long-term trend in the Vietnam upwelling under a high-emission scenario for the period 2006–2100, using simulation results from a global eddy-resolving climate model. In this model, the summertime Vietnam upwelling is projected to intensify in the 21st century and is statistically significant between 12°N and 14°N. A volume flux budget analysis indicates that wind stress curl is the most important contributor to the intensification. The geostrophic flow, to some extent, may suppress the upwelling intensification. The projected increase in upwelling is shown to significantly reduce local ocean warming and freshening and thus may have vital impacts on the local climate and circulation.