Tuesday, 4/25/06, 3:10 pm (EN6085A).

Boundary Layer Dynamics and Eddy Fluxes in Horizontal Roll Convection During Lake-Effect Snow Storms

Lake-effect snowstorms impact the lives, industry and property of areas that lie in their path, and improved knowledge of these storms can assist in forecasting the intensity and placement of high snow fall associated with them. Thus, it is important to increase our understanding of atmospheric boundary layer (BL) dynamics and eddy-flux processes in order to improve upon the handling of these events by forecast models. This research focuses on lake-effect snow caused by horizontal roll vortices and non-roll BL convection formed during cold air outbreaks (CAO) over Lake Michigan in January 2004. Aircraft and 3mm Doppler radar measurements taken by the Wyoming King Air research aircraft and the Wyoming Cloud Radar are used to: 1) study the characteristics of horizontal roll dynamics in lake-effect snow storms over Lake Michigan using single and dual Doppler analysis along with other aircraft data and 2) identify and characterize the role horizontal roll convection plays in the placement and magnitude of eddy fluxes of sensible and latent heat of these systems. To accomplish this two cases are evaluated: the first on January 22, 2004, where roll structure was evident in the ground based radar and aircraft data and the second on January 31, 2004, where roll structure was not prevalent, but convection was visible.