A study of the development of extratropical cyclones with an analytic model. Part I: the effects of stratospheric structure

Abstract

A new five-layer, quasigeostrophic model of baroclinic development is utilized. It is found that idealized tropospheric baroclinic systems do not show typically observed characteristics unless certain stratispheric temperature, geopotential, and wind anomaly configurations associated with tropopause undulations are present. Furthermore, for given tropospheric patterns, there are particularly lower-stratospheric configurations that optimize the development of model lower-tropospheric cyclones. These stratospheric configurations are functions of: 1) the value of the lower-stratospheric temperature anomaly, 2) the amplitude of the tropopause undulation, and 3) the horizontal location of the undulation relative to the tropospheric temperature anomalies. Finally, both the rate of cyclogenesis and the amplification of the tropopause undulation increase if tropospheric static stability is reduced. -from Authors