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We analyse the phenomenon of turbulent thermal diffusion that causes the non-diffusive streaming of aerosols in the direction of the heat flux and results in formation of large-scale aerosol layers in the vicinity of the temperature inversions. This phenomenon has been predicted theoretically and detected in the laboratory experiments conducted during recent years. We provide an insight into the existence of this phenomenon in the atmosphere and its potential impact onto aerosol distribution. We applied the theory of turbulent thermal diffusion to analyze the GOMOS aerosol observations near the tropopause and explained the shape of aerosol vertical profiles with elevated concentrations located almost symmetrically to the absolute temperature profile. We found an agreement between the theoretical predictions and the observations of the aerosol concentration and mean temperature profiles in the vicinity of the tropopause. These measurements in combination with the theoretical dependence of the turbulent thermal diffusion ratio on the turbulent diffusion yield an independent method for determining the coefficient of turbulent diffusion at the tropopause. We derived practically applicable formulations for dispersion of pollutants taking into account the phenomenon of turbulent thermal diffusion and preliminarily assessed the effects of turbulent thermal diffusion in modern dispersion models. In particular, we performed the numerical simulations of the sensitivity of the lower-troposphere vertical profiles of the aerosol concentration to the phenomenon of turbulent thermal diffusion. We found a regular upward forcing of the aerosols caused by turbulent thermal diffusion in the lower troposphere whereby heavier particles are affected stronger than the light aerosols.
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