Towards Improved Turbulence Model Parameterizations of the Stably Stratified Atmospheric Boundary Layer

Thursday, 18 December 2014
Jordan Wilson and Subhas Karan Venayagamoorthy, Colorado State University, Department of Civil and Environmental Engineering, Fort Collins, CO, United States
Connecting available field measurements with appropriate model parameters of turbulent mixing in the stably stratified atmospheric boundary layer remains an active research area. The research presented in this study extends the theoretical framework of Mater \& Venayagamoorthy (\textit{Phys. Fluids}, vol. 26, no. 3, 2014, 036601) on shear- and buoyancy-dominated regimes to the stable atmospheric boundary layer (SABL). Two pertinent length scales can be constructed to directly include the effects of shear and buoyancy, LkS=k1/2/S and LkN=k1/2/N, respectively, that are representative of large-scale motions in these two regimes. Model parameters are developed using observations from three field campaigns and further evaluated with an \textit{a priori} analysis of large-eddy simulation (LES) data of the SABL vertical structure. Results of this study thoroughly evaluate the pertinent mixing lengths applied to stably stratified turbulence in atmospheric observations and boundary layer models extendable to large-scale numerical weather prediction or global circulation models.

*S.K.V. gratefully acknowledges the support of the National Science Foundation under Grant No. OCE-1151838