Abstract
Parameterizations of biosphere–atmosphere interaction processes in climate models and other hydrological applications require characterization of turbulent transport of momentum and scalars between vegetation canopies and the atmosphere, which is often modeled using a turbulent analogy to molecular diffusion processes. Simple flux–gradient approaches (K theory) fail for canopy turbulence, however. One cause is turbulent transport by large coherent eddies at the canopy scale, which can be linked to sweep–ejection events and bear signatures of nonlocal organized eddy motions. The K theory, which parameterizes the turbulent flux or stress proportional to the local concentration or velocity gradient, fails to account for these nonlocal organized motions. The connection to sweep–ejection cycles and the local turbulent flux can be traced back to the turbulence triple moment 
Current affiliation: Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico.
© 2017 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
