The Study and Application of Baroclinic Ertel-Rossby Invariant in Meiyu Front Precipitation Process

In adiabatic and frictionless flow,Potential Vorticity (PV),characterized by its features of conservation,impermeability,and inversion,is widely used in diagnosis and analysis of the weather system over middle-high latitude. Due to its limitations of excluding the term of solenoid and of incapable of describing “fast-manifold” severe weather system, baroclinic Ertel-Rossby Invariant (ERI) proposed by Zdunkowski and Bott(2003) is analyzed and applied. The results show that under the condition of adiabatic and frictionless atmosphere,the expression of ERI includes the helicity,PV, and solenoid,and it can depict the “fast-manifold” systems,which make it possess huge potential practical value. Furthermore,the authors invoke ERI to diagnose a Meiyu front precipitation process from 3 Jul to 6 Jul 2003. The experiment reveals that the minimum of ERI coincides well with the 24-h accumulated rain band. Compared to PV,ERI is much capable in depicting and diagnosing the rainfall areas and rainfall amount.