Simulating aerosol microphysics with the ECHAM/MADE GCM ? Part II: Results from a first multiannual integration

A. Lauer (1) , J. Hendricks (1)

1 IPA - DLR Institut für Physik der Atmosphäre = DLR Institute of Atmospheric Physics

First results of a multiannual integration with the new global aerosol model system ECHAM4/MADE are presented. This model system enables explicit simulations of the particle number concentration and size-distribution, which is a fundamental innovation compared to previous global model studies considering aerosol mass cycles only. The data calculated by the model provide detailed insights into the properties of the global submicrometer aerosol regarding global burden, chemical composition, atmospheric lifetime, particle number concentration and aerosol size-distribution. The model takes into account sulfate (SO₄), nitrate (NO₃), ammonium (NH₄), black carbon (BC), organic matter (OM), mineral dust, sea salt and aerosol water. The simulated climatological annual mean global atmospheric burdens (lifetime) of the dominant submicrometer aerosol components are 2.25 Tg (4.5 d) for SO₄, 0.46 Tg (4.5 d) for NH₄, 0.26 Tg (5.6 d) for BC, and 1.77 Tg (6.5 d) for OM. The contributions of individual processes such as emission, nucleation, condensation or dry and wet deposition to the global sources and sinks of a specific aerosol component and particle number concentration are quantified. Based on this analysis, the significance of aerosol dynamical processes (nucleation, condensation, coagulation) is evaluated by comparison to the importance of other processes relevant for the submicrometer aerosol on the global scale. The results reveal that aerosol dynamics are essential for the simulation of the particle number concentration and important but not vital for the simulation of particle mass concentration. Hence aerosol dynamics should be taken into account in simulations of atmospheric processes showing a significant dependence on aerosol particle number concentration.

Domaines: Océan, Atmosphère

A. Lauer, J. Hendricks. Simulating aerosol microphysics with the ECHAM/MADE GCM ? Part II: Results from a first multiannual integration. Atmospheric Chemistry and Physics Discussions, 2006, 6 (4), pp.7519-7562. ⟨hal-00302050⟩