QUASI-STATIONARY ORGANIZED CONVECTION IN THE PRESENCE OF AN INVERSION NEAR THE SURFACE - EXPERIMENTS WITH A 2-D NUMERICAL-MODEL

Quasi-steady states of organized convection are studied in a two-dimensional nonhydrostatic primitive-equation numerical model. Uni- and multi-cellular patterns are identified in the presence of a low-level inversion, and discussed in relation to those obtained, by various authors, in the more traditional monotonic-sounding case. The stable layer near the ground is shown to be responsible for a configuration of flow normally not observed in cases of monotonic sounding and reminiscent of an orographically generated wave. Exploring the conditions conducive to quasi-steady convection it is found that, in the presence of a low-level inversion, a strong shear of the wind component perpendicular to the squall line is required near the surface, deeper than that required in the absence of the inversion.