Joint Seminar: Seeing Through the Haze of Aerosol Indirect Effects:

A perturbation in aerosol properties will alter microphysical properties of
clouds and precipitation, which will further affect cloud radiative properties and
hence exert an indirect effect on climate.  Quantitative evaluation of indirect aerosol effects on the Earth's climate has been clouded with two problems: the large uncertainty in forward estimates from global climate models, and the large discrepancy between these forward estimates and those inferred by constraining models with observations. This talk will focus on the physical mechanisms underlying these two puzzles: (1) the spectral shape of the cloud droplet size distribution, (2) representation of the autoconversion process (conversion of cloud water to rain water) in global climate models, and (3) turbulent entrainment and mixing processes. It will be shown that a significant fraction of the uncertainty and discrepancy arises from these three factors that have been poorly represented or ignored in global climate models. This talk will also discuss how to incorporate these effects into atmospheric models, and explore the challenges facing investigation of aerosol indirect effects.




13:30 h


Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg


Yangang Liu, US Dept. of Energy, Brookhaven National Laboratory,


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