摘要
When the horizontal grid size of a numerical weather prediction(NWP)model is between a few hundred meters and~10 km,referred to as the gray zone,updrafts in convective clouds cannot be fully resolved explicitly and the use of a subgrid convective cloud parameterization scheme is still necessary.Since some critical assumptions in the mass-flux formulation of conventional subgrid convective cloud parameterization become invalid for gray-zone resolutions,it is required for a generalized parameterization to be developed to properly describe subgrid convective clouds.To meet this requirement,a new subgrid convective cloud parameterization scheme that is based on the mass-flux formulation and suitable for gray-zone resolutions has been proposed and preliminarily tested in the Weather Research and Forecasting(WRF)model.This new scheme is automatically adaptive to variation in grid size(i.e.,scale-aware),and accounts for microphysical processes consistently with grid-resolved clouds.Numerical experiment of an idealized tropical cyclone shows that this new scheme has a substantial impact on the tropical cyclone’s intensity and precipitation distribution due to the effect of subgrid clouds on the total diabatic heating.
基金
supported by the Special Scientific Research Fund of Meteorological Public Welfare of China GYHY201206006
the National Science Foundation of China Grants 41175094,41575101.