9707730 Mourad The Lake-Induced Convection Experiment (Lake-ICE) is a multiple-investigator project whose ultimate goal is the understanding of how lake-effect conditions caused by cold air outbreaks over the Great Lakes, produce enhanced and debilitating snowfall downstream of the Great Lakes as well as influencing weather patterns in the northeast US. One approach to addressing this research problem is the documentation and explanation of the effects of enhanced surface fluxes of heat and moisture from Lake Michigan on multiscale turbulence. Multiscale turbulence is generally thought to be made up of three classes. The first is primarily two-dimensional roll vortices (or "large eddies") that scale with the boundary-layer depth and have axes aligned with the mean boundary-layer wind. The second class is sub-roll turbulence that also spans the boundary layer but is three dimensional and is typically convectively-driven. The third class of atmospheric turbulence, called "gust microfronts" or "ramps", is largely restricted to the surface layer and is driven by a combination of shear and convection. These three classes of turbulent structure evolve and interact in response to the enhanced fluxes from Lake Michigan into the overlying atmosphere. This study has four main goals. (1) The first is to examine the spatial evolution and distribution of gust microfronts utilizing in situ aircraft data. (2) Using the results of (1) and simultaneous synthetic aperture radar (SAR) images, the second goal is to test the hypothesis that SAR images can capture the spatially distributed stress patterns on the surface of the water created by multiscale atmospheric turbulence structure. (3) The third goal is to correlate geometric features in SAR images with those seen in satellite images of clouds and with basic parameters that describe boundary-layer structure. (4) The fourth goal is to work with several co-investigators under the umbrella of Lake-ICE to understand the interactions between large ed dies, km-scale thermals and ramps in lake induced convective boundary layers. Successful completion of this research will provide an improved knowledge of boundary layer fluxes over the Great Lakes and the ability to detect and classify various types of boundary layer turbulence using remote, spaced-based sensors.
Analysis of Multiscale Atmospheric Turbulence Structure Within the Surface Layer of Lake-induced Convention