1. European Network for Earth System Modeling (ENES) The PRISM Project Guy P. Brasseur Max Planck Institute for Meteorology Hamburg, Germany

2. The Climate System The climate system includes the atmosphere (dynamics, physics and chemistry), the ocean (dynamics and biogeochemistry), sea-ice, continental vegetation. It is subject to natural variability, and is affected by “external” perturbations (solar variability, volcanic eruptions, land-use changes, fossil fuel consumption, etc.)

3. Climate Modelling Climate simulations will require: –High resolution integrations (from 300 km to 30 km) –Ensemble integrations (with different initial conditions, and different model configurations) –Long-term integrations (several centuries) –More complex models (including the biological and chemical processes) Progress is limited by the availability of computing power.

4. European Network for Earth System Modelling (ENES) Network of university departments, research centres, meteorological services, computer centres and industrial partners working together towards: –the development, intercomparison and evaluation of Earth system models, –the exchanges of software, –the development of high-performance computing capability dedicated to high- resolution, multi-model ensemble integrations.

5. Two Projects PRISM: Programme for Integrated Earth System Modelling CLIMSTER: Climate Data Storage and Distribution as European Infrastructure

6. PRogramme for Integrated earth System Modelling (PRISM) An Infrastructure Project for Climate Research in Europe

7. The PRISM Project and coupling issues Context -Expertise in Europe is widely distributed -Development and application of sophisticated climate models localised in few national climate research centres - Multi-tera-scale supercomputer available within a few years but access to supercomputers restricted through national priorities -American and Japanese efforts: - USA: Accelerated Climate PRediction Initiative» (ACPRI) - Japan: «Earth Simulator Project» and «Frontier Research System» -> Europe needs to pool national efforts to establish a unified approach for Earth system modeling and match other initiatives

8. The PRISM Project and coupling issues Overall PRISM Objectives -> Develop a European portable, efficient and user- friendly Global Climate Modelling System based on actual models, and associated diagnostic/visualisation soft wares --> Undertake a pilot infrastructure project toward the establishment of a European Climate and Earth System Modeling Supercomputer Facility.

9. The PRISM Project PRISM Contributing Partners: -MPG-IMET, Germany (Dr. Guy Brasseur, coordinator) -KNMI, The Netherlands -MPI-MAD, Germany -Met-Office, United Kingdom -UREADMY, United Kingdom -IPSL, France -Météo-France, France -CERFACS, France -DMI, Denmark -SHMI, Sweden -NERSC, Norway -ETH Zurich, Switzerland -ING, Italy -MPI-BGC, Germany -PIK, Germany -ECMWF, Europe -UCL-ASTR, Belgium -NEC Deutschland -FECIT/Fujitsu -SGI Deutschland -SUN, Germany -> 97 person years (48 funded by European Commission for 4,8MEuros)

10. The PRISM Project Atmosphere: -MPG-IMET (ECHAM) -Météo-France (ARPEGE) -IPSL (LMDZ) -Met. Office (Unified Model) -UREADMY -ING Atmospheric Chemistry -MPG-IMET -UREADMY -IPSL -Met. Office -Météo-France -KNMI Land Surface -IPSL (Orchidée) -Met. Office -MPG-IMET -UREADMY -Météo-France (ISBA) Sea Ice: -NERSC -UCL-ASTR -Met. Office -IPSL -MPG-IMET Ocean Bio-geochemistry: -MPI-BGC -IPSL -MPG-IMET -Met. Office Ocean: -Met. Office (FOAM) -MPG-IMET (HOPE) -IPSL (OPA/ORCA) -UREADMY Regional Climate: -SHMI -DMI -Met. Office Coupler CERFACS (Oasis) PRISM components:

11. The PRISM Project T1: Detailed definition of a standard physical interfaces (nature of information to be exchanged) between the components. T2: Technical development of the coupler and coupling model interface library. T3: Physical and technical interfacing of existing state-of-art models European models. T4: Development of common diagnostic/visualization tools and data management system. T5: Development of a web-based interface for assembling and submitting a global climate model on the PRISM target platforms and for controlling the database archiving and post-processing. T6: Perform test runs to demonstrate the usefulness of the system.

12. The PRISM Project European Computers Available for PRISM Activities 1. ECMWF Europe Fujitsu VPP5000 and IBM SP4 2. DMI Denmark NEC SX-4 3. Météo-France France Fujitsu VPP5000 4. Idris France NEC SX-5 and IBM 5. ING Italy NEC SX-4 6. SARA The Netherlands Cray C-90 7. U. of Bergen Norway Cray T3E 8. SMHI Sweden Cray T3E, SGI 3000 9. CSCS Switzerland NEC SX-4 & SX-5 10. Hadley Centre United Kingdom Cray T3E 11. DKRZ Germany NEC SX-6

13. The future PRISM coupler: questions and concepts Develop a coupler, i.e. model coupling interface library + additional coupling processes, that will answer the PRISM system requirements. Key concepts for the PRISM coupler design: modularity and flexibility portability scalability and efficiency evolutivity

14. The future PRISM coupler: questions and concepts Questions to answer for PRISM coupler design -Characteristics of the PRISM coupled system (static or dynamic configuration, number of components, global or partial system, etc.) -Characteristics of the component models (CPU load, memory requirement, etc.) -Characteristics of the coupling fields (type, resolution, grid type, data decomposition, static or dynamically evolving, etc.) -Coupling parameters (number of coupling fields, frequency of exchange, …) -Target platform architecture (distributed memory vs shared memory, vector vs scalar, etc.) -Technical constraints (ex: implementation of message passing standards on the different machines) and operating system constraints => For present and next-generation climate modelling systems

15. PRISM coupler development Development of a Model Coupling Interface library (mo 1-12): CERFACS -> coupling initialisation -> parallel sending of coupling fields to sequential OASIS process -> parallel receiving of coupling fields from sequential OASIS process -> parallel exchange directly with other parallel model A A A O O O O OASIS A A A O O O

16. A possible PRISM configuration LS AC A A A O O C I C SI OB I+C c c c c c c c c c c cc cc cc cc C I C c c LS bc A A A c c c O O c c c c I+C c c c c c D T1T2time AC D c

17. Today, with current capability : To run an ensemble of 10 coupled climate models for 100 yrs: –Atmosphere: 50 km resolution, 70 levels, 50 chemical species, timestep=5 min. –Ocean: 0.1 degrees resolution, 50 levels timestep=20 min. Computer time required would be 60 years (20 years without chemistry) on the most advanced supercomputers.

18. ENES: The Project To develop a European Supercomputing Facility providing at least 5-10 Tflops (sustained) with associate data storage system and networking, remotely accessible to the Earth System scientific community.

19. ENES: The Project Budget: 200-300 Millions Euros Architecture should be adapted to the specific needs of the climate modelling. community, and take advantage of most recent technology. Should complement existing national facilities. Cooperation with Data-GRID

20. ENES: Conclusions A factor 100 increase in computing capability is urgently needed for climate modeling. Such increase is key for maintaining the influence of European efforts in future international climate assessments Such project can only be carried out at the European level with national participation. European networking of climate centres needs to be simultaneously enhanced.