| Popis: |
The hybrid mass flux convection scheme HYMACS has been proposed to simulate moist convection in non-hydrostatic numerical weather prediction models with grid sizes at which convection is partially resolved. Different to classical mass flux schemes HYMACS produces a net convective mass flux due to updrafts and downdrafts with resulting grid-scale pressure gradient forces. Thus, as a grid-scale reaction the environmental subsidence may cover several grid columns. Here, HYMACS is extended concerning the non-local effects of gust fronts and cell transport and aging in a way that convective cells can communicate also directly on the subgrid-scale without passing information only via grid-scale averages. Subgrid scale information of gust fronts from parameterized convective cells is used to initiate secondary cells by distributing a "trigger bonus" to neighboring grid columns. In addition, a cell age is assigned to convective cells to parameterize a temporal development in cloud top height and precipitation. This cell age is then transported on the grid-scale to simulate the advection of convective cells. The extentions of HYMACS are demonstrated by means of both idealized and real case experiments. |
