HR: 16:00h
AN: H24D-01    [Abstracts]
TI: Large Eddy Simulation of the diurnal cycle of the Atmospheric Boundary Layer
AU: Kumar, V
EM: vijayant@jhu.edu
AF: Center for Environmental and Apllied Fluid Mechanics, The Johns Hopkins University, Baltimore, MD 21218 United States
AU: Kleissl, J
EM: kleissl@mtu.edu
AF: Dept of Earth & Environmental Science, New Mexico Tech, Socorro, NM 87801 United States
AU: Meneveau, C
EM: menveau@jhu.edu
AF: Center for Environmental and Apllied Fluid Mechanics, The Johns Hopkins University, Baltimore, MD 21218 United States
AU: * Parlange, M B
EM: marc.parlange@epfl.ch
AF: School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, VD CH-1015 Switzerland
AB: High-resolution simulations of the atmospheric boundary layer are performed using Large Eddy Simulation with the scale-dependent Lagrangian subgrid scale model. The diurnal cycle of the atmospheric boundary layer is performed using the time series of surface heat flux measured at the HATS experiment as the surface boundary condition. The profile of Smagorinsky coefficient plotted as a function of the surface-layer stability parameter shows a strange hysteretic behavior, the strength of which increases with increasing distance from the surface. The subsequent use of local Richardson number (Ri) as the scaling parameter shows a decrease in the hysteresis. The profiles plotted as a function of the local obukhov length show no hysteresis which confirms the validity of Niewustadt's local scaling hypothesis for the presented case. Although the local scaling hypothesis was formulated for the stable boundary layer, it performs well for the entire stability regime of the diurnal cycle.
UR: http://eflum.epfl.ch
DE: 1818 Evapotranspiration
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 3307 Boundary layer processes
DE: 3379 Turbulence (4490)
SC: Hydrology [H]
MN: Fall Meeting 2005