(1) Department of Physics, Marquette University, Wehr Phys. Bld., Room 377, 540 North 15th Street, Milwaukee, WI, 53201-1881, U.S.A.
Abstract:
Convection in a quasi-steady, cloud-free, shear-free atmospheric boundary layer is investigated based on a large-eddy simulation model. The performed tests indicate that the characteristic (peak) values of statistical moments at the top of the mixed layer are proportional to the interfacial scales (from gradients of scalars in the interfacial layer). Based on this finding a parameterization is proposed for profiles of scalar variances. The parameterization employs two, semi-empirical similarity functions Fm(z/zi) andFi(z/zi), multiplied by a combination of the mixed-layer scales and the interfacial scales.