Large-eddy simulation of an idealized tropical cyclone

Large-eddy simulation (LES) of a tropical cyclone (TC) was carried out with with the Advanced Research Weather research and forecasting (ARW) model. It was demonstrated the use of a horizontal grid size < 100 m in a TC simulation produced three-dimensional turbulent eddies. These three-dimensional turbulent eddies had the effect of decreasing the maximum sustained wind and the maximum predicted azimuthally averaged wind. The investigations retained the same subgrid-scale parameterization near the sea surface. The model version of the tropical atmosphere was in an equilibrium state in which the thermodynamic field was moist-neutral according to the ARW-model thermodynamic and saturation-vapor-pressure equations. The model thermodynamic state was maintained by inclusion of a relaxation term in the thermodynamic equation with a time constant of 36 h.