Vertical Motion Response Within and Above the Marine Atmospheric Boundary Layer Driven by Ocean Current Feedback

Recent advancements in the study of ocean-atmosphere interactions have primarily focused on the influence of sea surface temperature (SST) and surface currents on the state of the ocean, while the corresponding atmospheric responses have received comparatively less attention. On the atmospheric side, the thermal feedback of the ocean onto the atmosphere has been well-documented: higher SSTs have been shown to enhance near-surface wind & wind stress due to increased boundary layer mixing and modified pressure gradients. These mechanisms can then induce wind & wind stress curl when there is a cross-wind SST gradient, and generate wind & wind stress convergence/divergence when there is an along-wind SST gradient. However, the feedback of ocean currents on the atmosphere has only recently been explored. Recent studies found that ocean currents aligning with the wind direction can attenuate wind stress and thus allow near-surface wind to increase. The opposite can be said for opposing wind and current directions. Additionally, some research indicates that accounting for this oceanic feedback in wind stress will produce vertical motion changes in the lower atmosphere through secondary circulation effects (e.g., Ekman processes), especially on the oceanic sub-mesoscale. In this study, we use coupled ocean-atmosphere models to investigate feedback from ocean currents to the atmosphere. By comparing simulations that account for oceanic current feedback with those that do not, we aim to elucidate the influence of oceanic currents on atmospheric dynamics, especially the vertical motion response propagating through and beyond the boundary layer. The results of this study are anticipated to advance our understanding of the coupled ocean-atmosphere system and contribute to the improvement of numerical predictions for these interactions.