A Study of the Development of Extratropical Cyclones with an Analytic Model. Part II: Sensitivity to Tropospheric Structure and Analysis of Height Tendency Dynamics

Abstract

Abstract An analytic quasigeostrophic model is used to examine the sensitivity of type B cyclogenesis to the vertical structure of the troposphere given a particular stratospheric temperature configuration. It is found that there is an optimal tropospheric configuration that produces the largest negative height tendency at the center of the 1000-mb model cyclone. Based on the response of the 1000-mb height tendencies, altering the baroclinicity in the model planetary boundary layer (PBL) does not significantly affect the instantaneous quasigeostrophic dynamics of the deep atmosphere. Rather, the PBL temperature anomalies affect the development of lower-tropospheric model lows by hydrostatically shifting or steering the cyclone centers to locations beneath more (or less) favorable deep atmospheric quasigeostrophic conditions for development. Diagnostic analyses of three individual stratospheric-tropospheric model configurations are also performed to examine the dynamics that drive the height (pressure) ten...