Sensitivity of some African heavy rainfall events to microphysics and planetary boundary layer schemes: Impacts on localised storms
Agostino N. Meroni, Kizito Amua Oundo, Richard Muita, Mary‐Jane M. Bopape, Robert Maisha, Martina Lagasio, Antonio Parodi, G. Venuti
Abstract
Abstract High‐resolution numerical weather prediction (NWP) simulations of heavy rainfall events are known to be strongly sensitive to the choice of the sub‐grid scale parameterisation schemes. In the African continent, studies on such a choice at the convective‐resolving scales are not numerous. By exploiting a state‐of‐the‐art NWP model, the Weather Research and Forecasting (WRF) model, the sensitivity of the simulation of three heavy rainfall events in Sub‐Saharan Africa to the microphysical (MP) and planetary boundary layer (PBL) schemes is studied. Validating the numerical outputs against rainfall satellite estimates, ground‐based weather stations, radiosonde profiles and satellite‐derived cloud‐top temperature maps with an object‐based tool, the best‐performing setup is identified. In terms of heavy rainfall forecast location, it is found that the PBL scheme has a greater impact than the MP, which is shown to control the cloud‐top temperature simulation. Among the schemes considered, the best performances are achieved with a six‐class single‐moment microphysical scheme and a non‐local planetary boundary layer scheme which properly includes the vertical mixing by the large eddies in the atmosphere.