Boundary Layer Coherent Structures (MBL ARI)
1997
Shirer, Hampton N. | Young, George S.
It is well known that a substantial portion of the air/sea fluxes of heat, moisture, and momentum is accomplished via intermittent processes, processes that are poorly understood at the present time. Recently, it has been demonstrated that coherent structures in the marine boundary layer (MBL) are responsible for this flux intermittency. These coherent structure types include such secondary circulations as two-dimensional rolls (cloud streets), three-dimensional convective cells (thermals), and shear driven eddies (billows). These features occur in different atmospheric boundary layer thermal stratification and shear regimes; some are forced primarily by thermodynamic, and others by dynamic, mechanisms. Our ultimate goal is to determine the mechanisms underlying the intermittency in air/sea fluxes produced by these coherent structure types. As summarized below, we are using a variety of complementary statistical/mathematical approaches to objectively identify the spatial and temporal characteristics of these structures. Our primary data sources include both the high resolution output produced by the Penn State version of Moeng's Large Eddy Simulation (LES) code and observations from the MBL ARI experiments performed in 1995 off the California coast.
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