133364 20260218073314.0 doi 10.1016/j.ocemod.2024.102359 sideral 138077 ART-2024-138077 eng (orcid)0000-0003-3570-0202 Llorente, Víctor J. Universidad de Zaragoza Sensitivity of boundary layer features to depth-dependent baroclinic pressure gradient and turbulent mixing in an ocean of finite depth 2024 Access copy available to the general public Unrestricted The present numerical study builds on Ekman (1905)’s work in surface boundary layer and extends the boundary value problem to overcome some of its limitations. Previous studies addressed model’s limitations by assuming that deviations from observations are usually ascribed to different eddy viscosity shapes, but seldom to the presence of baroclinic pressure gradients and shallow seas, which are the mainstays of this work. Improved solutions in the ocean boundary layer are obtained considering both depth-dependent wind-induced eddy viscosity and horizontal density gradients, ranging from well-mixed to highly-stratified conditions in a finite-depth ocean. High-order numerical solutions extend those in previous analytical and numerical works in the literature and widens the parameter space analyzed. Remarkably, the current profiles are obtained without ambiguity as a truly superposition of a geostrophic and a ageostrophic terms. Results indicate that, for a vertically-uniform eddy viscosity without density gradients and in shallow waters, currents are practically aligned with wind. As depth increases, misalignment between currents and wind increases and the complexity of the vertical structure increases. At large depths, Ekman’s values are attained, i.e., deflection angles relative to wind direction, , are − = −45◦ at the surface, where the current is maximum, and − = −90◦ for the depth-integrated transport (negative for deflections to the right in the Northern Hemisphere). These features remain regardless of the magnitude of the eddy-viscosity. For non-uniform eddy viscosity, − decreases from −45◦ up to −90◦ from low to high stratification level, respectively, whereas − is rather insensitive ( − ≈ −90◦). Contrary to wind effects, the presence of the only vertically-uniform density gradient forcing, with constant eddy viscosity, deflects the surface angle − = +45◦ relative to the densitygradient direction, , in deep waters. Maximum currents no longer occur at the surface in this case. For non-uniform density-gradient profiles, current magnitude decreases overall while − ≈ +45◦ as long as the gradient affects the entire surface boundary layer. The deflection angle − ∼ +95◦ remains less sensitive to changes in density-gradient profile. info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 2.9 2024 OCEANOGRAPHY 16 / 65 = 0.246 2024 Q1 T1 METEOROLOGY & ATMOSPHERIC SCIENCES 53 / 111 = 0.477 2024 Q2 T2 0.906 2024 Computer Science (miscellaneous) 2024 Q1 Oceanography 2024 Q1 Geotechnical Engineering and Engineering Geology 2024 Q1 Atmospheric Science 2024 Q2 5.0 2024 info:eu-repo/semantics/article info:eu-repo/semantics/submittedVersion Padilla, Enrique M. Díez-Minguito, Manuel 2005 595 Universidad de Zaragoza Dpto. Matemática Aplicada Área Matemática Aplicada 189 (2024), 102359 [18 pp.] Ocean model. OCEAN MODELLING 1463-5003 8471778 http://zaguan.unizar.es/record/133364/files/texto_completo.pdf Preprint info:eu-repo/date/embargoEnd/2025-03-19 585787 http://zaguan.unizar.es/record/133364/files/texto_completo.jpg?subformat=icon icon Preprint info:eu-repo/date/embargoEnd/2025-03-19 oai:zaguan.unizar.es:133364 articulos driver 2026-02-17-20:22:08 ARTICLE