Ocean Sciences Editors' Highlights

Wind Stress is not the Ceiling of Momentum Flux to the Ocean

The ocean is mainly driven by wind stress, but simultaneous observations show that the gain of momentum flux by the ocean can be larger than the wind stress due to the influence of ocean waves.

Source: Journal of Geophysical Research: Oceans


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Wind stress is the most important momentum source (if not the only one) for the upper ocean. Hence, it is straightforward to assume that the momentum flux in the upper ocean is less than or equal to the wind stress. However, Huang and Qiao [2021] report simultaneous in-situ observations, which separated the turbulent stresses above and beneath the ocean surface. Results contradict the traditional assumption by showing that the momentum flux in the upper ocean boundary layer can be significantly larger than the wind stress due to modulations by surface gravity waves. The new findings introduce a new challenge (maybe also a new controversy) to ocean dynamics. In the future, more sophisticated observations such as these will be needed, in addition to a breakthrough in oceanography theory and a new principle in ocean modelling.

Huang, C. J., & Qiao, F. [2021]. Simultaneous observations of turbulent Reynolds stress in the ocean surface boundary layer and wind stress over the sea surface. Journal of Geophysical Research: Oceans, 126, e2020JC016839. https://doi.org/10.1029/2020JC016839

―Lei Zhou, Editor, JGR: Oceans

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