Validation studies of turbulence closure schemes for high resolutions in mesoscale meteorological models

Abstract

Mesoscale models are often used to reproduce the atmospheric processes at relatively high resolutions, both for meteorological and pollutant dispersion studies and applications. Particularly in non-homogeneous conditions, a proper description of turbulent transport is a fundamental aspect. In this work, we compare two analogous 1.5-order turbulence schemes implemented in RAMS, mainly differing in the form of the turbulent kinetic energy dynamical equation (1D or 3D) and in the relationships linking the closure quantities, such as diffusion coefficients and dissipation terms. We present results from simulations performed in a simple, idealized case, along with results related to two field campaigns carried on in the Tsukuba region (Japan) in 1989 and 1990. Both turbulence schemes are able to well reproduce the mean flow, but different performances are related to the turbulence field.