Position of the project

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.

ESGF grid

ESGF is a unfunded federated international effort coordinated by multiple agencies and partners including Institut Pierre Simon Laplace (IPSL). METAFOR (2009-2011) was a European Union FP7 project and provided detailed metadata for climate models developing the CIM ontology (Common Information Model) to describe climate data and the models that produce it in a standard way. ES-DOC is also a unfunded federated international effort towards climate models and simulations documentation. IS-ENES1 (2009 – 2013) and IS-ENES2 (2014 – 2018) are European Union FP7 projects providing integrative research and service activities for the European Earth System Modelling community, including support for distribution of the CMIP5 archive through ESGF. The G8 initiative’s support of ExArch has provided a critical opportunity to develop a long-range internationally coordinated strategy to address the goals and requirements of exascale climate analysis.

IPSL being the coordinator of METAFOR, IS-ENES 1 and 2, and an ExArch and ES-DOC principal investigator play a prominent role in those projects. International coordination with respect to the scientific climate data management issues is done through those projects. They are the link with projects or initiative like CURATOR (NSF, NASA. NOAA): capable infrastructure for Earth system research and operations and GO-ESSP (Global Organization for Earth System Science Portals): a federation of frameworks that can work together using agreedupon standards.

This international collaboration culminates every five to seven years during the highly visible CMIP phase. It is mandatory for the French climate community to remain at the forefront on those topics in the future. CONVERGENCE will give us the opportunity to reduce the delay between simulations, distribution and analysis of high quality and well documented and referenced data to a wide variety of users. Research collaborators and partners will benefit from a better access to climate data. This has the potential to give a strong competitive advantage to the national research teams. Private companies making use of our data like insurance companies, energy suppliers or companies working on climate change impacts will as well benefit from a better access to highly traceable climate data and will thus be keen to further exploit partners data. These companies currently restrict their study to a very limited sample of simulations and datasets (the sample they have an easy access to).

CONVERGENCE principally address axis number 3 of the project call by engaging with class of problems where data volume and complexity is a major brake at every stage of climate simulations, pre-processing, runtime, data management and data analysis. CONVERGENCE will also address axis number 1 of the project call by engaging with class of problems that needs innovative algorithms and approach to evaluate model and parameters uncertainties in a multi-physic and multi-scale context. CONVERGENCE platform will favour the climate modelling ecosystem development through multidisciplinary consortium, wide adoption and training.

IDRIS experts will bring there knowledge in HPC use and environment and has been involved in DEISA and PRACE. IDRIS has been work package leader and member of the executive committee of the DEISA project. They are now a PRACE work package leader. They will be involved in scientific data management. MDLS seeks to accompany, support and stimulate scientific communities to make the best use of supercomputers, especially deployed as part of the European project PRACE and the French national centres under GENCI. MDLS organizes training sessions in the following fields: distributed parallel programming, hybrid programming (OpenMP/MPI), GPU computing, debugging and parallel sparse linear algebra. MDLS hosts and gives support to several HPC oriented Masters programs and will extend it through CONVERGENCE platform trainings.

Strategy

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.

Challenges

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).

Key objectives of the climate modelling platform

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).