Geoscientific Model Development Discussions www.geosci-model-dev-discuss.net 1991-9611 1991-962X 2 2 2009 10.5194/gmdd-2-797-2009 http://www.geosci-model-dev-discuss.net/2/797/2009/ http://www.geosci-model-dev-discuss.net/2/797/2009/gmdd-2-797-2009.html http://www.geosci-model-dev-discuss.net/2/797/2009/gmdd-2-797-2009.pdf 797 843 2009-07-07 OASIS4 – a coupling software for next generation earth system modelling R. Redler rene@r-redler.de S. Valcke H. Ritzdorf NEC Research Laboratories, NEC Europe Ltd., Sankt Augustin, Germany CERFACS, Toulouse, France In this article we present a new version of the Ocean Atmosphere Sea Ice Soil coupling software (OASIS4). With this new fully parallel OASIS4 coupler we target the needs of Earth system modelling in its full complexity. The primary focus of this article is to describe the design of the OASIS4 software and how the coupling software drives the whole coupled model system ensuring the synchronization of the different component models. 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