Diabatic Heating and Generation of Available Potential Energy in a Tornado-Producing Extratropical Cyclone

Abstract

Diabatic heating by latent heat release and longwave radiation and corresponding generation of available potential energy have been computed for a tornado-producing cyclone system. Also, the contributions of two subareas, encompassing the immediate cyclone vicinity and the convection area, to the cyclone system generation are examined applying the concepts of limited region baroclinic and barotropic generation. Heating values, which are dominated by convective latent heat release, are generally in good agreement with observed weather features and cyclone development. The resulting positive cyclone system generation is comparable with previous studies and is strongly influenced by the contributions made by the two subareas. In turn, the latter are dominated by their. barotropic components, indicating that the heating fields in these subareas contribute more effectively to increasing or maintaining the baroclinicity of the cyclone system than of the subareas themselves.