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Communication Dans Un Congrès Année : 2010

Study of vertical transport of marine aerosol using an unsteady 2D model

Résumé

Marine aerosols constitute one of the most significant part to the global aerosol field. The marine aerosol is thus of major importance to Earth's radiative balance and climate system at global scale. At a more regional or local scale, it will have a significant contribution to the electromagnetic propagation in the MABL or impact on ecosystems and vegetation in coastal area. The vertical transport is an important process involved in the concentration of marine aerosol particles in the atmosphere, but models commonly used do not take thermal stability effects into account. The present study focuses then on this last point, with the help of a new model. The Marine Aerosol Concentration Model (MACMod) is a fully 2D unsteady model, developed to simulate the concentration of marine aerosol particle in coastal area. It takes into account different source functions for the surf-zone and the open ocean, the deposition on sea surface, the turbulent dispersion, the atmospheric stability and the advection due to the wind. The model uses either a computed meteorological field or an analytical field, with possible time-dependent environmental conditions. MACMod is tested by comparison with concentrations measured during experimental campaigns held in the coastal Mediterranean area, for various stability conditions. Then, it is used to calculate the concentration of aerosol downwind the shoreline, for several values of radius, wind speed and Air-Sea Temperature Difference. The influence of the various parameters is analyzed and the under or over-concentrations (compared to neutral case) is quantified. It is found that the thermal stability has an increased effect for low wind speeds. The 10m height concentration of submicronic and supermicronic aerosol behaves in an opposite way: when the concentration of the former is increased for stable conditions, it is decreased for the latter. This could explain some apparently surprising experimental results. Above 10m/s, the thermal stability effect is lowered. These results will be, in the future, used to correct and improve parametric models, better estimate sea-salt particle deposition onto coastal vegetation, as well as the amount of condensation nuclei produced by the marine surface.
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Dates et versions

hal-00807861 , version 1 (04-04-2013)

Identifiants

  • HAL Id : hal-00807861 , version 1

Citer

Gilles Tedeschi, Jacques Piazzola. Study of vertical transport of marine aerosol using an unsteady 2D model. 31th NATO ITM Meeting on Air Pollution Modelling and its application, Sep 2010, Turin, Italy. paper 4.9. ⟨hal-00807861⟩
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