Development of a new hybrid cumulus parameterization scheme for use in nonhydrostatic weather prediction models

点击翻译按钮获取中文摘要

The purpose of the proposed research project is to develop a new nonlocal and hybrid cumulus parameterization (NHCP) scheme for use in nonhydrostatic numerical weather prediction (NWP) models. NHCP will be based on a mass flux approach. By implementing NHCP in a NWP model the following forecast skills shall be improved: i) spatial and temporal distribution of convective clouds and precipitation, ii) stratiform precipitation as induced by convective overturning, iii) subgrid-scale peak values of convective precipitation, iv) mesoscale organization of cumulus convection. The nonlocal character of the NHCP scheme is given by the fact that the evolving cumulus cloud will not be fixed to a particular grid point, instead it may be transported over several grid points so that cloud mass fluxes are locally not balanced. Furthermore, cumulus convection will be treated in a hybrid way, that is only parts of a cumulus convection event will be parameterized, certain cloud processes will be directly considered in the dynamic model. During the first two years of the proposed research the principle core of the NHCP scheme shall be developed.