The Dynamics of Circulations within the Trailing Stratiform Regions of Squall Lines. Part II: Influence of the Convective Line and Ambient Environment

Abstract

Abstract A dynamic version of the two-dimensional kinematic cloud model of Rutledge and Houze is used to study the individual roles of hydrometeor and heat advection from the convective line to the stratiform region of the 10–11 June 1985 PRE-STORM squall line. The design of the model allows for specified inputs of hydrometeors, heat, and water vapor from the convective line. Convective heating alone generates significant ascent and condensate in the anvil; however, surface rainfall is scarce without the advection of hydrometeors from the convective line. Hydrometeor advection alone does not produce strong ascent in the anvil cloud, implying the important additive effects of both heat and hydrometeor advection in generating broad regions of significant stratiform rainfall. The roles of individual microphysical processes within the stratiform region are examined, along with the sensitivity of stratiform region dynamics to postconvective region environmental conditions. Of the processes evaporation, melting...