Objective Aerosol particles modify the radiative properties and the lifetime of clouds in the atmosphere, and possibly result in severe changes in the global climate that influence human lives (aerosol indirect effect). To better understand the effect of aerosols on clouds and the climate, representations of the activation process of aerosols to form cloud droplets is a crucial factor. Sensitivity studies on different parameterizations of the activation process will be conducted in a climate model to investigate their performances and optimize the representation of this process. Two important mechanisms will be incorporated in the parameterization of the activation process in the climate model. One is the kinetic effect. Including this effect, the activation process w ill be parameterized in the climate model more realistically and the model can predict the cloud droplet number concentration more accurately. The second mechanism is the dispersion effect, in which the influence of an increasing number of aerosols on the cloud droplet size distribution will be included and its impact on the aerosol indirect effect will be investigated. Both modifications on the parameterization of the activation process will be tested against in-situ observational data in the proposed research project. The goal is to simulate the aerosol-cloud interaction more realistically and efficiently in the global climate model, to reduce the uncertainty of model estimates of the aerosol indirect effect and to improve our understanding of future climate change. Fields of science natural sciencesearth and related environmental sciencesatmospheric sciencesclimatologyclimatic changes Keywords Aerosol indirect effect aerosol cloud interactions in the global climate model model estimate of aerosol indirect effect Programme(s) FP6-MOBILITY - Human resources and Mobility in the specific programme for research, technological development and demonstration "Structuring the European Research Area" under the Sixth Framework Programme 2002-2006 Topic(s) MOBILITY-2.1 - Marie Curie Intra-European Fellowships (EIF) Call for proposal FP6-2004-MOBILITY-7 See other projects for this call Funding Scheme IIF - Marie Curie actions-Incoming International Fellowships Coordinator MAX PLANCK INSTITUTE FOR METEOROLOGY Address Germany See on map EU contribution € 0,00