Atmospheric data mean motions

This means that larger scale motions can be explicitly resolved and deterministically forecasted. The smaller scale motions, namely turbulence, are not explicitly resolved. Rather, the effects of those sub-grid scales on the larger scales are approximated by turbulence models. These smaller size motions are said to be parameterized by sub-grid scale stochastic (statistical) approximations or modes. The referred experimental data analyzes of the flow in the atmospheric boundary layer determine the basis for the large eddy simulation (LES) approach developed by meteorologists like Deardorff [27] [29] [30]. Large-Eddy Simulation (LES) is thus a relatively new approach to the calculation of turbulent flows. 

LIQUID DIFFUSIVITIES. The theory of diffusion in liquids is not as advanced or the experimental data as plentiful as for gas diffusion. The diffusivities in liquids are generally four to five orders of magnitude smaller than in gases at atmospheric pressure. Diffusion in liquids occurs by random motion of the molecules, but the average distance traveled between collisions is less than the molecular diameter, in contrast to gases, where the mean free path is orders of magnitude greater than the size of the molecule. 

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