The investigators will attack a basic but unsolved problem in numerical modeling in the atmospheric and oceanic sciences -the proper formulation in a numerical model of the subgridscale turbulence when the scale of the grid size in the numerical model (d) is of the order of the scale of the energy-containing turbulence (L). Current mesoscale models tend to contain eddy-diffusivity models of the type proposed many years ago and this approximation was adequate when d was much greater than L. Preliminary work by the research team has revealed, however, that new formulations are required as d approaches L.
The investigators will first install the new formulation in a high-resolution large eddy simulation (LES) model. They will compare the scalar and velocity statistics obtained with the standard and new formulation in atmospheric boundary-layer (ABL) simulations. Since the two sets of results should not be significantly different, this provides a model validation test.
The investigators will then install the new formulation into an advanced mesoscale model and study the impact on simulations of moist convection. They will also continue the simulations of ABL flows. The goal is to document the performance of the new model as d approaches L.
The work is expected to impact numerical modeling in applications where the grid mesh size is of the order of the scale of the turbulence. This occurs in high resolution meteorological modeling in applications ranging from regional weather prediction to simulations of severe storms and hurricanes.
