The primary purpose of this project is to develop a platform capable of running large ensembles of simulations with a suite of models, to handle the complex and voluminous generated datasets, to facilitate the evaluation and validation of the models and the use of higher resolution models. The goal is to help model development, to facilitate and reinforce the French contribution to demanding and highly visible project like CMIP and CORDEX (Coordinated Regional Climate Downscaling Experiment).

The platform will be built on ongoing efforts to homogenize and to unify generic elements of the French climate models. So as to unify and homogenize platform's components a dedicated communication bus will be implemented. The French community has adopted a flexible approach to climate modelling based on “families” of models within which a suite of configurations addressing different aspects of our scientific guiding questions are defined. The model families may differ in various ways: resolution, vertical extent, horizontal domain (e.g. global or regional), active parameterization, complexity (e.g. atmosphere-only, coupled atmosphere-ocean, carbon cycle, ocean biogeochemistry, etc. ), etc… But the different members of one family must share the same basic physical properties and any changes in their configuration must be limited to those required to address specific scientific questions. Such imbrications of model families and configurations pose considerable challenges that we propose to address in CONVERGENCE.

The U.S. NRC Panel Report “A National Strategy for Advancing Climate Modelling” identifies the challenge we plan to address as an urgent priority. This view is shared by DOE, NOAA, NASA, EC FP7, WMO, and other agencies (http://dels.nas.edu/Report/National-Strategy-Climate-Modeling/13430).

Increasing computational capabilities is mandatory in climate modelling to achieve higher spatial and temporal resolution, better physical process representation, explicit modelling of more biogeochemical processes, longer runs and larger ensembles. Adequate strategies and software environments integrated into specialised platforms are absolutely mandatory to sustain the development of the next generation of French climate models and the analysis of climate simulations as we are entering the Big Data era and facing the Exascale horizon.

The new comprehensive software platform will be built on ongoing efforts to homogenise and unify generic elements of the French ESMs software environment. These elements include data structure definition and IO, code coupling and interpolation, as well as runtime and pre/post-processing environments. Because it will provide the fabric through which we connect our models to state-of-the-art HPC systems, the development of a comprehensive platform demands expertise in HPC and informatics that cuts across the individual partners and the broader HPC community. Our next generation platform will be based on modern and open practices in software engineering, and will be readily usable by climate scientists. The ability to vary the configuration and the resolution of the model, to perform large ensembles of runs, to provide a precise evaluation and validation of the model will constitute a unique framework to help model development. It will provide a considerable support to the French community for his contribution to demanding and highly visible climate project like CMIP.

 

Several international projects currently running or recently ended address part of those issues and CONVERGENCE partners contributed to them. Also, due to his multidisciplinary nature, CONVERGENCE is one of the very few initiative to date in such a position to fill gaps in our ability to effectively use the models we develop, to analyse their outputs and associated observations, and ultimately to answer guiding scientific questions.

Earth System Grid Federation (ESGF) is a group of archive service providers and software developers, developing and deploying a robust, distributed data and computation platform using open source software.

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