How physical parameterizations can modulate internal variability in a regional climate model
Résumé
We analyze here to what extent the internal variability simulated by a regional climate model is sensitive to its physical parameterizations. The influence of two convection schemes is quantified over Southern Africa, where convective rainfall predominates. Internal variability is much larger with Kain-Fritsch scheme than for Grell-Dévényi at both the seasonal, intraseasonal and daily timescales, and from the regional to the local (grid-point) spatial scales. In addition to the domain settings and the lateral forcing conditions extensively analyzed in the literature, the physical package appears thus as a key factor that modulates the reproducible and irreproducible components of regional climate variability.