Long‐Term Variation of the Deepwater Overflow Associated With the Sea Level Change Across the Luzon Strait

The Luzon Strait deepwater overflow (LSDO), as the only deep‐ocean connection between the Pacific and the South China Sea, plays an important role in regulating the region's overturning circulation. However, the mechanism responsible for its long‐term variations has not been fully understood. In this study, we extend the traditional hydraulic theory to a continuously stratified ocean and evaluate the LSDO transport using the pressure differences between the two sides of the Luzon Strait, yielding a mean transport estimate of 1.23 Sv over the past 3 decades. The proposed method fills the gap of the traditional hydraulic theory and reveals the importance of upper‐ocean variations. The results indicate that changes in sea surface height dominate the long‐term variations in the deep‐ocean pressure differences that drive the LSDO across the Luzon Strait.