International Journal of Marine Science, 2024, Vol.14, No.4, 245-255 http://www.aquapublisher.com/index.php/ijms 251 6 Theoretical Models and Simulations 6.1 Numerical modeling of wave-ABL interactions Numerical modeling of wave-atmospheric boundary layer (ABL) interactions is crucial for understanding the complex dynamics at the air-sea interface. A simplified atmospheric boundary layer model, ABL1d, has been developed and integrated into the Nucleus for European Modelling of the Ocean (NEMO) to improve the representation of air-sea interactions in oceanic models. This model aims to capture key processes associated with air-sea interactions at mesoscale oceanic scales, showing good agreement with observations and fully coupled ocean-atmosphere models (Lemarié et al., 2020). The Weather Research and Forecasting (WRF) model has been enhanced with a moving bottom boundary condition to simulate realistic meteorological and wave conditions, validating the model with idealized test cases and demonstrating satisfactory agreement with literature results (Zhu et al., 2023). 6.2 Simulation of turbulence and energy fluxes Turbulence and energy fluxes in the ocean surface boundary layer (OSBL) are significantly influenced by surface and submesoscale processes. Observations and simulations indicate that surface processes, such as winds and waves, dominate turbulent kinetic energy (TKE) dissipation, while submesoscale processes play a lesser role (Buckingham et al., 2019). Large-eddy simulations (LES) coupled with Lagrangian stochastic models have been used to explore wave-driven OSBL turbulence, capturing Langmuir turbulence and breaking wave effects, which enhance near-surface dispersion and turbulent diffusivities (Kukulka and Veron, 2019). Wave-turbulence interactions have been shown to enhance vertical mixing in the ocean, which is critical for general ocean circulation models and climate studies (Qiao et al., 2016). 6.3 Validation of models with observational data Validation of theoretical models with observational data is essential to ensure their accuracy and reliability. The ABL1d model integrated into NEMO has been tested against several boundary-layer regimes and evaluated using standard metrics, showing very good agreement with observations (Lemarié et al., 2020). Similarly, the WRF model with moving bottom boundary conditions has been validated with idealized test cases, demonstrating accurate simulation of turbulent flows over moving waves (Zhu et al., 2023). Observations from moorings in the North Atlantic have been used to quantify the contributions of surface and submesoscale processes to TKE dissipation, supporting the dominance of surface processes in turbulent exchanges. Comparisons between theoretical predictions and observations from a tower on Östergarnsholm Island in the Baltic Sea have demonstrated the significant impact of surface waves on near-surface wind profiles and turbulence structure (Song et al., 2015). 7 Challenges and Future Research Directions 7.1 Limitations in current observational techniques Current observational techniques face significant limitations in accurately capturing the complex interactions within the atmospheric boundary layer (ABL) over the ocean. For instance, the challenging conditions in the Southern Ocean have led to sparse spatial and temporal coverage of observations, increasing uncertainty in atmosphere and ocean dynamics (Swart et al., 2019). Similarly, the lack of high-resolution observations in the rotor-swept area of offshore wind turbines constrains the validation of numerical models, which is crucial for understanding the physics of atmospheric flow within and around wind plants (Shaw et al., 2022). While scanning LiDAR systems have shown promise in measuring micro-scale wind-wave interactions, their application is still limited to specific conditions, such as old-sea states where waves travel significantly faster than the mean wind 3. 7.2 Improving model accuracy Improving the accuracy of models that simulate the ABL dynamics over the ocean requires addressing several key challenges. One major issue is the need for better subgrid-scale parameterizations within highly non-linear models, as current computing capabilities cannot resolve all relevant spatial and temporal scales simultaneously. The implementation of moving wave boundary conditions in models like the Weather Research and Forecasting (WRF) model has shown potential in simulating realistic meteorological and wave conditions, but further validation and
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