A numerical study of the structure of convective roll clouds associated with high latitude cold air outbreaks

Organized convective roll clouds are an important form of boundary layer convection which often occur over the high latitude ocean during cold air outbreaks.. We will present numerical simulations of these roll clouds that have been performed with a cloud resolving model developed at Nagoya University. Three-dimensional simulations were performed at very high spatial resolutions (~500m in the horizontal and ~25m in the vertical) in a domain of sufficient size so as to allow for the development of multiple cloud bands. In this talk, we will discuss the non-linear interaction that exists between the cloud bands and the background environmental wind profile. The vertical momentum transport associated with this interaction can result in an acceleration of the surface wind field and a concomitant increase in the magnitude of the surface fluxes of sensible and latent heat. We will also discuss the production of snow and graupel in the cloud bands.