The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

Subsurface turbulent mixing can significantly impact local sea surface temperature, thereby affecting regional weather patterns and the global climate system. However, the spatial distribution of subsurface turbulent mixing remains poorly understood. In this study, we evaluate a high-resolution ocean model's ability to simulate strong subsurface mixing events. We present spatial patterns of its occurrence, mixing strength, and thickness, which highlight the central equatorial Pacific as the most affected area of subsurface mixing. Argo-measured subsurface overturn events show a comparable core in the central equatorial Pacific, so it is realistic and deserves attention. In the core region, strong mixing can penetrate tens of meters beneath the surface mixed layer. Associated with intense subsurface mixing, maximum downward turbulent heat flux, which would result in cooling above this maximum and warming in the deeper layer, also tends to occur several to tens of meters below the subsurface mixed layer in the core region. This study illustrates a wide coverage of subsurface mixing and discusses its important thermal effects. These findings have implications for improving climate prediction and projection.

subsurface mixing, equatorial Pacific, Argo observation, high-resolution simulation