Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 9 24 2009 10.5194/acp-9-9471-2009 http://www.atmos-chem-phys.net/9/9471/2009/ http://www.atmos-chem-phys.net/9/9471/2009/acp-9-9471-2009.html http://www.atmos-chem-phys.net/9/9471/2009/acp-9-9471-2009.pdf 9471 9489 2009-12-16 <i>Est modus in rebus</i>: analytical properties of multi-model ensembles S. Potempski S. Galmarini stefano.galmarini@jrc.ec.europa.eu European Commission – DG Joint Research Centre, Institute for Environment and Sustainability, 21020 Ispra VA, Italy Institute of Atomic Energy, 05-400 Otwock-Swierk, Poland In this paper we investigate some basic properties of the multi-model ensemble systems, which can be deduced from a general characteristic of statistical distributions of the ensemble members with the help of mathematical tools. 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