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2025/03/10 12:00 Dr. Jen-Ping Peng（University of Western Australia, Australia）
Seminar
Poster： ╱ Post date：2025-03-05NCU IHOS Seminar Announcement
Speaker：Dr. Jen-Ping Peng
Place：S-325, Science Building 1
Abstract：
Title：Frontiers in Surface Mixed Layer Dynamics and Turbulence
Speaker：Dr. Jen-Ping Peng
University of Western Australia, Australia
Time：03/10（Mon.）12：00
Place：S-325, Science Building 1
Abstract：
The surface mixed layer (SML) has long been recognized as a key regulator of energy, momentum, and gas exchange between the atmosphere and the ocean, playing a fundamental role in large-scale upper-ocean dynamics. However, recent research has highlighted the importance of fine-scale dynamics, such as diurnal warm layers (DWLs) and surface-layer fronts, in modulating mixing, stratification, and vertical transport within the SML. While both processes have been studied individually, their interactions remain largely unexplored. This study investigates the coexistence and interplay of DWLs and surface-layer fronts using field observations and a turbulence closure model in an eddy-rich tropical ocean subjected to intense solar heating and weak winds. We found that the presence of a DWL isolates the deeper layers of the SML from diabatic and frictional surface forcing, causing these layers to quickly become non-turbulent while remaining in a state of marginal stability. This condition suggests that small perturbations from local processes, such as internal tides and waves, can easily trigger instability and turbulence. Additionally, frontal dynamics were observed to deepen the SML, allowing near-surface diurnal shear associated with DWL dynamics to penetrate to greater depths during nighttime, compared to conditions without a front, thereby facilitating the vertical transport of heat and tracers. Our findings underscore the necessity of accurately representing the interactions between DWLs and surface-layer fronts to enhance the precision of ocean circulation and climate models.
Last modification time：2025-03-05 PM 2:57
