HR: 16:20h
AN: A34C-02    [Abstracts]
TI: The importance of aerosol water for air pollution effects on weather and climate
AU: * Metzger, S
EM: metzger@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Department of Atmospheric Chemistry, J.J. Becherweg 27, Mainz, 55128, Germany
AU: Lelieveld, J
AF: Max Planck Institute for Chemistry, Department of Atmospheric Chemistry, J.J. Becherweg 27, Mainz, 55128, Germany
AB: We apply a new concept to study air pollution effects on weather and climate, which is based on thermodynamic principles that explain hydration and osmosis - including the required transformation of laboratory based concepts to atmospheric conditions. Under ambient conditions the equilibrium relative humidity (ERH) determines the saturation molality, solute and solvent activities (and activity coefficients), and the aerosol associated water mass, sine the water content is fixed by ERH for a given aerosol concentration and type. As a consequence, aerosol water drives the gas/liquid/solid aerosol partitioning, ambient aerosol size-distributions and directly links aerosol hygroscopic growth into fog, haze and clouds. Various modeling results indicate that a) our new concept is not limited to dilute binary solutions, b) sensitive aerosol properties such as the pH of binary and mixed inorganic/organic salt solutions up to saturation can be computed accurately, and c) that anthropogenic emissions can be directly linked to visibility reduction, cloud formation and climate forcing, if we explicitly account for the aerosol water mass. Our new concept is more explicit than the traditional CCN concept as it abandons the use of ambiguous terms such as "marine" and "continental" aerosols, and refines lumped categories such as mineral dust, biomass burning, sea salt, organic or sulfate aerosols currently used in atmospheric modeling. Despite, our concept is computationally very efficient as it allows solving the whole gas/liquid/solid aerosol partitioning analytically without numerical iterations. It is therefore especially suited for regional high resolution, or global climate applications.
UR: http://www.atmos-chem-phys.net/7/3163/2007/acp-7-3163-2007.html
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0320 Cloud physics and chemistry
DE: 1600 GLOBAL CHANGE
DE: 1637 Regional climate change
DE: 3311 Clouds and aerosols
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting