An intercomparison of radiatively driven entrainment and turbulence in a smoke cloud, as simulated by different numerical models

As part of a programme of intercomparison of eddy‐resolving and one‐dimensional (1‐D) boundary‐layer models, a convective boundary‐layer filled with radiatively active ‘smoke’ was simulated. the programme is sponsored by the Global Energy and Water Experiment Cloud Systems Study. Cloud‐top‐cooling rates weire chosen to be comparable with those observed in marine stratocumulus, while avoiding evaporative feedbacks on entrainment and turbulence that are also important in liquid‐water clouds. the radiative‐cooling rate hacl a specified dependence on the smoke profile, so that differences between simulations could only be a result of different numerical representations of fluid motion and subgrid‐scale turbulence. At a workshop in De Bilt, the Netherlands in August 1995, results from numerous groups around the world were compared with each other and with a previously investigated laboratory analogue to the smoke cloud.

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