10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Adsorption of Trace Atmospheric Gases in Atmospheric Boundary Layer by Dust Aerosol Particles Emitted from Arid Source Areas
BORIS KRASOVITOV, Tov Elperin, Itzhak Katra, Andrew Fominykh, Ben-Gurion University of the Negev, Israel
Abstract Number: 881 Working Group: Remote/Regional Atmospheric Aerosol
Abstract Scavenging of active trace gases by mineral dust storm aerosols is a result of gas adsorption. Adsorption of trace atmospheric gases such as NO2, SO2 and HNO3 by dust aerosol particles contributes to the evolution of concentration distribution of the trace constituents and can affect subsequent chemical reactions in the atmosphere. In this study we suggest a two dimensional model of adsorption of trace atmospheric constituents by mineral particulate matter emitted from area source in a desert. The model is based on the application of theory of turbulent diffusion in the atmospheric boundary layer (ABL) in conjunction with the model of gas adsorption by porous solid particles. The analysis is focused on the local spatial scale (10 km), which is the most important for dust entrainment into the atmosphere. The numerical model is formulated using parametrizations based on the aeolian experiments. Aeolian field experiments were performed at a dust source site (loess soil in Northern Negev, Israel) using a portable boundary layer wind tunnel to determine the emitted PM fluxes for different wind speeds and varying soil conditions. For individual wind-erosion events, wind shear produced turbulence near the surface is responsible for particle entrainment into the atmosphere, while turbulence in the atmospheric boundary layer affects particle diffusion and deposition. Therefore the wind velocity profiles used in the simulations were fitted from our data previously obtained in field measurements conducted in the Northern Negev (Israel) using the experimental wind mast. Size distribution of the emitted dust particles in the numerical simulations was taken into account using a Monte Carlo method. We determined numerically concentration distributions of the particulate matter and trace gas based on the values of shear velocity and emitted dust flux from the soil measured in experiments. Analysis was performed for the meteorological conditions typical for the Northern Negev region. The obtained results demonstrate that using parametrizations based on direct field measurements of wind profile and aeolian erosion has a potential to reduce the uncertainties in atmospheric particulate matter transport and trace gases distribution models and provides a more realistic assessment of dust and trace gases concentration distributions. The model enhances our capacity of quantification of atmospheric dust effects in climate models as well as health risk assessment. The results of the present study can be useful in an analysis of different meteorology-chemistry models including adsorption of trace atmospheric gases by dust aerosol particles emitted from arid source areas.