Turbulent Dispersion of Non-Uniformly Emitted Passive Tracers in the Convective Boundary Layer

Abstract The impact of spatially non-uniform emissions on the turbulence dispersion of passive tracers in the convective boundary layer is studied by means of large-eddy simulation. We explicitly calculated the different terms of the budget equations for the concentrations, fluxes and variances. We used sub-domain averaging where each subdomain is of typical size of a large-scale model grid cell.We found that the concentration profiles in the sub-domain where the emission takes place are lightly affected by the size of the emission release. This effect becomes more relevant in the downwind subdomain. Although sub-domain averaged fluxes are not affected by the emission source size, concentration variances are dramatically increased when the emission shrinks. This increase originates from the mixing of highly concentrated air parcels with low concentrated ones. We also found that the concentration variance at the surface is driven neither by the position of the emission source nor the strength of the shear forcing but solely by the emission variance.

VINUESA J.;  GALMARINI Stefano; 

2009-12-07

SPRINGER

JRC49906

0006-8314,   

http://www.springerlink.com/content/83p77m3384083818/,    https://publications.jrc.ec.europa.eu/repository/handle/JRC49906,   

10.1007/s10546-009-9416-0,