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The model is tested for the first GABLS case. The simulation starts with a neutral boundary layer capped with an inversion and then surface cooling is applied. A constant cooling rate is applied to the surface, resulting in a weakly stable, quasi-stationary boundary layer about 150-200 meters deep. The results from the new turbulence model compares well with large eddy simulation results for the same case.
In the hierarchy of models, this energy similarity closure model is situated between the 1- 1.5-order closures, retaining either none or one auxiliary equation for turbulence, and the second order models that utilize 10 extra equations for all the second order moments of the flow. By using two equations for describing the turbulence field, we avoid the use of a mixing-length scale, and allow third-order flux divergences to affect the turbulence budgets in fundamentally different ways for momentum and heat. This is the case for gravity waves, which are generated in the boundary layer by the turbulence and emitted to the free troposphere. This is possible in the long-lived stable boundary layer found during winter and in polar and coastal regions, as shown in previous studies by one of the authors.
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