Application of Generalized Moist Potential Vorticity to the Analysis of a Torrential Rain Case

Considering the non-uniform saturation of the real atmosphere, a diagnostic study of a torrential rain event is performed from the perspective of the anomaly of the generalized moist potential vorticity (GMPV) after introducing the generalized potential temperature into the thermodynamic frame of the real atmo- sphere. The results show that the anomaly appeared at mid-lower levels of the troposphere when the torrential rain happened. Analysis of the magnitudes and locations of maximum values of the tendency of the GMPV indicates that the anomaly of the GMPV was closely related to the occurrence of torrential rain. Therefore, the GMPV could be used to forecast and diagnose the occurrence of torrential rain in operational application.