Transport Asymmetry in Skewed Convective Circulations

Abstract

Two simple kinematical models are used to describe the asymmetry in bottom-up and top-down diffusion in the convective boundary layer. Both models resolve the mean circulation with narrow updrafts and wider downdrafts but differ in the treatment of horizontal branches of the circulation. The models indicate that the transport asymmetry arises from the nonstationarity of the concentration field, the skewness of the flow field, and the inhomogeneous manner by which the species is introduced into the updrafts and downdrafts.