Abstract—
Approximations are proposed for the Ekman thickness scale, in which the Coriolis parameter is replaced by absolute vorticity to consider the variability of the parameters of the planetary boundary layer in the generalized vorticity equation. This leads to a semiempirical nonlinear model of the boundary layer, which is used to calculate the integral parameters of the boundary layer included in the generalized vorticity equation. In numerical experiments with the interaction model of a pair of barotropic atmospheric vortices such as tropical cyclones, the influence of the parameters of the nonlinear boundary layer model on the evolution of the vorticity field is demonstrated. In particular, it is shown that the inclusion of the nonlinear friction term, which is determined by the second spatial derivatives of the integral parameters of the boundary layer, can lead to the divergence of cyclones under certain conditions, and its exclusion can lead to their merging.
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Funding
This work was carried out as part of the state assignment of the Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, topic no. 0271-2019-0011 (no. АААА-А17-117030110037-8) with financial support from the Russian Foundation for Basic Research for project nos. 18-05-80011 and 19-55-10001.
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Permyakov, M.S., Zhuravlev, P.V. & Semykin, V.I. Nonlinear Model of the Ekman Boundary Layer in the Generalized Vorticity Equation. Izv. Atmos. Ocean. Phys. 56, 585–590 (2020). https://doi.org/10.1134/S0001433820060080
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DOI: https://doi.org/10.1134/S0001433820060080