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Pré-Publication, Document De Travail Année : 2024

A generalized stochastic formulation of the Ekman-Stokes model with statistical analyses

Résumé

In this study, a novel stochastic formulation for the upper ocean Ekman boundary layer is derived from scaling the generalized stochastic Craik-Leibovich equations. This formulation encodes the interactions between wind, waves, and currents through the introduction of the uncertainty of unresolved motions, using established physical parameterizations. Numerical investigations of the time-dependent stochastic Ekman-Stokes model, incorporating wave mixing and stochastic transport effects, reveal Ekman velocities with an increased uncertainty, a higher kinetic energy and a stronger occurrence of extreme events, compared to traditional solutions. Stronger correlations between zonal and meridional components are obtained, with more skewed distributions and extreme values, particularly near the surface. A sensitivity analysis highlights the impact of transient winds and surface waves on statistical moments. Transient winds reduce vertical shear, deepen circulation, and increase uncertainty. Smaller surface waves also lead to higher ensemble energy and stronger correlations. Energy and transport magnitude peak when mean waves and wind are aligned, decreasing with rotation and redistributing current velocity statistics. These findings underscore the model's enhanced ability to help capture complex ocean dynamics with improved uncertainty representation.
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Dates et versions

hal-04672188 , version 1 (17-08-2024)

Identifiants

  • HAL Id : hal-04672188 , version 1

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Long Li, Etienne Mémin, Bertrand Chapron. A generalized stochastic formulation of the Ekman-Stokes model with statistical analyses. 2024. ⟨hal-04672188⟩
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