Abstract:
Recent advances in supercomputing have made feasible the numerical integration of high-resolution cloudresolving
models (CRMs). CRMs are being used increasingly for high-resolution operational numerical
weather prediction and for research purposes. We report on the development of a new CRM in South Africa.
Two bulk microphysics parameterisation schemes were introduced to a dynamical core of a two-dimensional
Non-hydrostatic σ-coordinate Model (NSM) developed in South Africa. The resulting CRM was used to
simulate two 12-day periods and an 8-day period observed during the Tropical Oceans Global Atmosphere
Coupled Ocean-Atmosphere Response Experiment. The response of the NSM to the large-scale forcing
which occurred over the three periods, and which included both suppressed and active convection, was
examined. The NSM is shown to be able to capture the differences in the three experiments and responds
correctly to the large-scale forcing (i.e. it is able to distinguish between suppressed and active regimes).
However, the model simulations are cooler and drier than the observations. We demonstrate progress made
in the development of a CRM in South Africa, which can be used to study the attributes of convective rainfall
over the region.
