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Boundary-Layer Meteorology

, Volume 133, Issue 1, pp 1–16 | Cite as

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

  • Jean-François Vinuesa
  • Stefano Galmarini
Article

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, and used sub-domain averaging where each sub-domain is the 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 sub-domain. 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 those of low concentrations. 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.

Keywords

Convective boundary layer Large-eddy simulation Non-uniform emission Scalar flux Scalar variance Turbulent dispersion 

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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.Institute for Environment and SustainabilityJoint Research Centre, European CommissionIspraItaly

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