OWLeS: Ontario Winter Lake-effect Systems

Summary

The OWLeS project examines the formation mechanisms, cloud microphysics, boundary layer  processes and dynamics of lake-effect systems (LeS) using new observational tools capable of  detailing LeS characteristics not observed in previous LeS field experiments. Lake-effect  systems form through surface-air interactions as a cold air mass is advected over relatively warm  (at least partially) ice-free mesoscale bodies of water. The OWLeS project focuses on Lake  Ontario because of its geometry and size, influence of upstream lakes, frequency of LeS, nearby  modest orography, and proximity to several participating universities with a strong record of  undergraduate research. We distinguish between short-fetch LeS (those oriented at large angles  to the long axis of the lake) and long-fetch LeS (those more aligned with the lake's long axis).

  The overarching objectives of the OWLeS project are to: 

1.  understand the development of, and interactions between, internal planetary boundary layers (PBL) and residual layers resulting from advection over multiple mesoscale water bodies and intervening land surfaces
2. understand the processes involved in the development of lake-effect snows over the New York Finger Lakes and how these processes differ from the larger Great Lakes
3. examine how organized, initially convective LeS structures in short-fetch conditions persist far downstream over land, long after leaving the buoyancy source (i.e., the icefree water) 
4. examine how surface fluxes, lake-scale circulations, cloud microphysics and radiative processes affect the formation and structure of long-fetch LeS 
5. understand dynamical and microphysical processes controlling the fine-scale kinematic structures and electrification processes of intense long-fetch LeS 
6. provide in situ validation of operational (S-band) and research (X-band) dualpolarization hydrometeor type classification and lake-effect snowfall QPE 
7. understand the influence of downwind topography on LeS generated over Lake Ontario