Testing PDF-base Parameterizations with LES

Description

A class of cloud and turbulence parameterizations is based on the use of an assumed PDF. The parameters of the PDF are determined from first, second, and third moments of the distribution. The moments, in turn, are obtained using higher-order closure. Large-eddy simulation (LES) can be used to test the parameterizations, in three distinct ways. First, LES can be used to test the goodness of fit of an assumed PDF. Second, LES can be used to test the methods used to determine the parameters of the PDF from the moments. Finally, LES can be used to test the methods used to determine the moments themselves. We are performing such tests, using simulations of stratocumulus clouds, shallow cumulus clouds, and deep convection.