Open AccessTurbulence Closure Parameterization and Grid Spacing Effects in Simulated Supercell Storms
Author(s) -
Elisabetta Fiori,
Antonio Parodi,
F. Siccardi
Publication year - 2010
Publication title -
journal of the atmospheric sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.853
H-Index - 173
eISSN - 1520-0469
pISSN - 0022-4928
DOI - 10.1175/2010jas3359.1
Subject(s) - supercell , turbulence , meteorology , closure (psychology) , numerical weather prediction , environmental science , storm , parametrization (atmospheric modeling) , convective storm detection , large eddy simulation , grid , severe weather , convection , range (aeronautics) , clear air turbulence , geology , physics , materials science , geodesy , quantum mechanics , economics , market economy , composite material , radiative transfer
Many meteorological organizations plan to substantially increase the resolution of the limited-area models used for severe weather prediction. Such an approach does not guarantee a priori the reduction of the uncertainty of the decision maker in the prediction of severe weather impact. A deep moist convective process, a supercell, is studied in a simplified atmospheric scenario by means of high-resolution numerical simulations with the Consortium for Small-Scale Modeling (COSMO) model. Different turbulence closure models and their impact on the spatiotemporal properties of storm processes are discussed. In the range of grid spacing between 1 km and 100 m, also termed “terra incognita,” the simulations of a supercell converge with respect to flow field structure, transport properties, and precipitation fields when a turbulence closure derived from large-eddy simulation (LES) is used. In contrast, more simplified turbulence closures such as 1D (vertical) boundary layer approximations yield substantially worse results than the 0.2-km LES reference simulation.