A Lake Breeze on the Eastern Shore of Lake Michigan: Observations and Model

Abstract This study was undertaken to determine the physical and dynamical characteristics of the lake breeze wind system at a site on the eastern shore of Lake Michigan. Lake breeze development and progress inland were observed by hourly pilot balloon ascents in a vertical plane perpendicular to the lake shore. The fields of moisture and temperature in this vertical plane on a day when a clearly defined lake breeze occurred were obtained using an instrumented aircraft. Observations were made during periods when prevailing external meteorological conditions would exert minimum influence on the local thermal circulation. Over the land the depth of the layer of onshore flow is approximately 750 m and a maximum velocity of 5–7 m sec−1 is observed within 250 m of the surface directly over the lake shore. Above the lake breeze current a well defined return flow is apparent by midafternoon. The layer of return flow is about twice as deep as the lake breeze and velocities in the return flow axe proportionately l...