Mesoscale Structures in the Lake-Induced Convective Boundary Layer

Mesoscale structures were observed with in situ aircraft measurements taken as part of the Lake-Induced Convection Experiment (Lake-ICE), during winter-time cold air outbreaks over Lake Michigan. While it has long been known that both three-dimensional mesoscale cellular convection and two-dimensional mesoscale roll vortices are common under such conditions, detailed in situ observations of their structure has been lacking. Lake-ICE aircraft observations provided both turbulence and microphysical data from within such mesoscale structures. With these observations, we document the relationship between mesoscale cloud structures and the associated microphysical and turbulence variations. In particular we document the close and repeatable relationships between mesoscale structures in the microphysical and turbulence fields. The broad range of turbulence, chemical, and microphysical measurements available from the NCAR Electra allow us to diagnose the physical basis for many of these relationships. We also document the dependence of the existence and structure of these mesoscale convective features upon environmental conditions, noting that the environments for which these phenomena dominated the turbulence and microphysical behavior of the convective boundary layer were very different from those for which they did not.