Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 6531-6546, 2017
https://doi.org/10.5194/acp-17-6531-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
02 Jun 2017
A new downscaling method for sub-grid turbulence modeling
Lucie Rottner, Christophe Baehr, Fleur Couvreux, Guylaine Canut, and Thomas Rieutord Météo-France – CNRS, CNRM/GAME, UMR 3589, 42 avenue Coriolis, 31100 Toulouse, France
Abstract. In this study we explore a new way to model sub-grid turbulence using particle systems. The ability of particle systems to model small-scale turbulence is evaluated using high-resolution numerical simulations. These high-resolution data are averaged to produce a coarse-grid velocity field, which is then used to drive a complete particle-system-based downscaling. Wind fluctuations and turbulent kinetic energy are compared between the particle simulations and the high-resolution simulation. Despite the simplicity of the physical model used to drive the particles, the results show that the particle system is able to represent the average field. It is shown that this system is able to reproduce much finer turbulent structures than the numerical high-resolution simulations. In addition, this study provides an estimate of the effective spatial and temporal resolution of the numerical models. This highlights the need for higher-resolution simulations in order to evaluate the very fine turbulent structures predicted by the particle systems. Finally, a study of the influence of the forcing scale on the particle system is presented.

Citation: Rottner, L., Baehr, C., Couvreux, F., Canut, G., and Rieutord, T.: A new downscaling method for sub-grid turbulence modeling, Atmos. Chem. Phys., 17, 6531-6546, https://doi.org/10.5194/acp-17-6531-2017, 2017.
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Short summary
In this study we explore a new way to model sub-grid turbulence using particle systems. The ability of particle systems to model small-scale turbulence is evaluated using high-resolution numerical simulations performed with the atmospheric model Meso-NH. The study shows that the particle system is able to reproduce much finer turbulent structures than the high-resolution simulations. It also provides an estimate of the effective spatial and temporal resolution of the numerical models.
In this study we explore a new way to model sub-grid turbulence using particle systems. The...
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