Global Simulation of Dust Aerosol with a Chemical Transport Model, MASINGAR

[摘要] We have developed a dust aerosol module integrated into a global aerosol transport model, called MASINGAR (Model of Aerosol Species IN the Global AtmospheRe). The dust module treats dust-emission processes based on the saltation-bombardment theory. A global soil texture database is used to determine the size distribution of parent soils. Erodibility factors for vegetation cover, snow cover, land-use type, and soil type are considered. Dry and wet deposition processes are dependent on particle size.To obtain a climatological global dust emission, deposition, and spatial distribution, we performed a 25-year simulation which is assimilated to the 1979-2003 condition, using a nudging scheme. The simulated annual mean global emission flux and atmospheric dust load (with 0.2 ≤ D ≤ 20 μm) are 2149 (1817-2339) Tg yr−1 and 17.9 (15.6-20.4) Tg. The surface concentrations and depositions are compared with observed data, and the dust emission flux is compared with previous model studies. The model reproduces the simulated seasonal variation of dust concentration at stations near East Asian dust sources, where most previous models have underestimated the amounts and amplitudes. The global simulation results indicate that the quantitative estimation of the dust budget is sensitive to the size distribution of the emitted dust.

[学科分类] 大气科学