ATSC colloquium Thursday, April 19, 2007, 3:00 pm, EN 6085A

Abstract:

Shallow marine stratocumulus decks are semi-permanent features to the west of the major continents. Because of the increase in albedo of the cloud layer compared to that of the underlying ocean surface, coupled with the low cloud-top heights and vast horizontal extents typical of marine stratocumulus, these cloud layers exert a significant cooling effect on global climate. This effect, along with interest in boundary-layer processes has motivated numerous field observations campaigns and numerical simulations of the stratocumulus-topped boundary layer aimed at understanding the processes that control the characteristics and extent the cloud layer. Despite these efforts, much about these cloud layers remains poorly understood -- in particular the roles that drizzle and mesoscale organization play in modifying the characteristics of the cloud layer. 

Observations and preliminary analyses from the recent Dynamics and Microphysics in Marine Stratocumulus (DMIMS) field campaign will be presented along with results from previous studies of marine and near-coastal stratocumulus conducted using the University of Wyoming King Air and/or the Wyoming Cloud Radar. In this project, the King Air was used to track the evolution of ‘drizzle-cells’ – examples of mesoscale cellular convection defined by the presence of high-reflectivity drizzle cores. Finally, a look forward to an upcoming marine stratocumulus field campaign, planned for November 2008 off the coast of Northern Chile, will be presented.