Release of Potential Instability: Part II. The Mechanism of Convective/Mesoscale Interaction

Abstract In Part I the convective processes important during the release of potential instability were described qualitatively and evaluated quantitatively in a parameterized cumulus model within a primitive equation model. Part II includes a more detailed examination of convective/mesoscale interactions through a basic simulation experiment and tests under different physical conditions and with different computational grids. The cumulus model was documented in Part I and the primitive equation model is documented herein. The example, for which detailed dynamical fields are shown, began with 6 h of convective activity that developed a saturated neutrally buoyant mesoscale updraft which produced the bulk of the precipitation by 12 h into the integration. The potential instability process is readily understandable and verifiable in general terms by numerical simulation. Increasing moisture bandwidth or large-scale ascent results in a wider precipitation band. Permitting evaporation of convective precipitati...