Penetrative turbulence associated with mesoscale surface heat flux variations
Abstract
This article investigates penetrative turbulence in the atmospheric boundary layer. Using a large eddy simulation approach, we study characteristics of the mixed layer with respect to surface heat flux variations in the range from 231.48 W/m to 925.92 W/m, and observe that the surface heterogeneity on a spatial scale of km leads to downscale turbulent kinetic energy cascade. Coherent fluctuations of mesoscale horizontal wind is observed at 100m above the ground. Such a surface induced temporal oscillations in the horizontal wind suggest a rapid jump in mesocale wind forecasts, which is difficult to parameterize using traditional one-dimensional ensemble-mean models. Although the present work is idealized at a typical scale (20km) of surface heterogeneity, the results help develop effective subgrid scale parameterization schemes for classical weather forecasting mesoscale models.
Keywords
Cite
@article{arxiv.1505.00448,
title = {Penetrative turbulence associated with mesoscale surface heat flux variations},
author = {Jahrul M. Alam and M. Alamgir Hossain},
journal= {arXiv preprint arXiv:1505.00448},
year = {2015}
}