عنوان مقاله [English]
A review of past work in the subject areas of latent heat release in extra tropical cyclones, within the concept of the potential vorticity framework or “PV thinking” is presented. It is also aimed to assess to what extent the conventional baroclinic instability theory can be applied to extra tropical cyclones involving intense latent heat release. The main results of the previous studies concerning the effect of latent heat release on extra tropical cyclones dynamics can be divided into two categories, depending on whether the impact of the adiabatically generated PV anomaly on the baroclinic dynamics was very weak or strong. In the weak cases, cyclogenesis is primarily driven by baroclinic dynamics, with latent heat release playing a secondary role. Latent heating influences the baroclinic dynamics as simply by superposing a positive PV anomaly near the cyclone center without significantly altering the PV structure elsewhere. On the other hand, a few studies reveal that latent heat release can enhance largely the cyclone intensity, particularly when the surface thermal gradients are weak and alter significantly the structure of upper-level PV and surface thermal anomalies. The low-level adiabatically produced PV anomaly is able to substitute for the absent surface warm anomaly.