1. PRISM Coupling and I/O System G. Berti, P. Bourcier, A. Caubel, D. Declat, M.-A. Foujols, J. Latour, S. Legutke, J. Polcher, R. Redler, H. Ritzdorf, T. Schoenemeyer, S. Valcke and R. Vogelsang The 5 th International Workshop on Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003

2. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 2 Presentation outline 1 – PRISM General Presentation 2 - PRISM Goals 3 - PRISM Scientific and Technical Standards 4 - PRISM Coupling and I/O System 5 - PRISM first coupler: Oasis 3.0

3. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 3 1 – PRISM General Presentation -PRISM: PRogram for Integrated Earth System Modelling -A European project, started December 2001, funded by the European Commission (4.8 M€) -Coordinators: -Guy Brasseur (MPI, Hamburg) -Gerbrand Komen (KNMI, Amsterdam) -PRISM Director: Reinhard Budich (MPI)

4. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 4 1 – PRISM General Presentation => 22 partners: leading climate research institutes and computer vendors MPG-IMET, Germany KNMI, Netherlands MPI-MAD, Met-Office, UK UREADMY, UK 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 Europe FECIT/Fujitsu SGI Europe SUN Europe

5. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 5 2 - PRISM Goals Help climate modellers spend more time on science: Provide software infrastructure to easily assemble Earth system coupled models based on existing state-of-art European components models launch/monitor complex/ensembles Earth system simulations Define and promote technical and scientific standards for Earth System modelling Undertake a pilot infrastructure project toward, on the longer term, the establishment of a European Climate and Earth System Modeling Supercomputer Facility.

6. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 6 2 - PRISM Goals Atmosphere: Météo-France (ARPEGE), MPG- IMET (ECHAM), IPSL (LMDZ), MetOffice (Unified Model), UREADMY, INGV Atmospheric Chemistry: MPG-IMET, UREADMY, IPSL, MetOffice, Météo-France, KNMI Land Surface: IPSL (Orchidée), MetOffice, MPG-IMET, UREADMY, Météo- France (ISBA) Sea Ice: NERSC, UCL-ASTR, MetOffice, IPSL, MPG-IMET Ocean Biogeochemistry : MPI-BGC, IPSL, MPG- IMET, MetOffice Ocean: UREADMY, MetOffice (FOAM), MPI-M (HOPE), IPSL (OPA/ORCA) Regional Climate: SHMI, DMI, MetOffice Coupler: CERFACS, NEC, CCRLE, FECIT, SGI, MPI-MAD

7. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 7 3 - PRISM scientific and technical standards Scientific standards:  Physical interfaces  Global Earth System parameters Technical standards:  Architecture and User Interface  Coupler and I/O  Data and grid format  Coding and quality Interaction with other groups (ESMF, ESG/NOMADS, CF...)

8. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 8 4- PRISM Coupling and I/O System PRISM Coupling and I/O System = Model Interface Library (PSMILe) + Driver+ Transformer -Programming language: Fortran 90 and C -All sofware produced are open source –Coupling and I/O system use freely available open source software products external libraries, hidden from the model developer (MPICH, LAM-MPI, NetCDF, libXML, mpp_io, SCRIP, …) –Vendors may provide optimized versions for specific independent software components (e.g. MPI, NetCDF) Keynotes - PSMILe – Driver - Transformer

9. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 9 4 - PRISM Coupling and I/O System Keynotes - PSMILe – Driver - Transformer Insures data coupling exchanges between any two component models either directly or via or the transformer including repartitioning with MPI1 or MPI2 Insures data input/output from/to files =>Switch between coupling exchanges and input/output is: indicated by the user in a coupling configuration file (XML) transparent for the component model managed automatically by the PSMILe OB C C C O1 C C OB C C C file OB C C C O2 T T C C

10. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 10 4 - PRISM Coupling and I/O System Concise and extendable interface Coupling data produced by a source model can be consumed by more than one target model and at a different frequency. Coupling data may be only partially consumed by the target model (extraction of subspaces, hyper-slabs or indexed grid points). Local operation on the coupling data can performed before exchange. Keynotes - PSMILe – Driver - Transformer

11. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 11 Different classes of primitives insuring:  The Startup phase Initialization; prism_init(…), … Termination of definition; prism_enddef(…)  The Definition phase Definition of Grid; prism_def_grid(…), prism_set_mask(…), … Definition of Data; prism_def_var(…)  The Transfer of fields Exchange or I/O of Data; prism_put(…), prism_get(…)  The Termination phase Termination of PRISM application; prism_terminate(…) 4 - PRISM Coupling and I/O System Keynotes - PSMILe – Driver - Transformer

12. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 12 Launching of component models: - static: all at beginning of simulation (MPMD or SPMD) Distribution of global information: - initial date, calendar, coupling parameters, etc. Component model monitoring: - centralises all logging messages sent by the models during the simulation (timestep, restart saved, etc.) 4 - PRISM Coupling and I/O System Keynotes - PSMILe – Driver - Transformer

13. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 13 Different transformations: Spatial interpolation: nearest-neighbour, bilinear, bicubic, conservative remapping, … Other spatial transformations: flux correction, merging, etc. General algebraic operations Combination of coupling data produced by one model may have to be combined before the exchange. On different types of fields 1D, 2D, 3D, 4D, scalar or vector, static or dynamic structure On different types of grids regular, gaussian, stretched, reduced, unstructured, etc. 4 - PRISM Coupling and I/O System Keynotes - PSMILe – Driver - Transformer

14. Deployment Phase V3 V6 V2 V1 V4 V5 V7 Mj SMIOC V1 : cf SCC V4 : cf SCC user Mk SMIOC V4 : cf SCC V5 : in, fileV5, TnlV5k user Mi SMIOC V1 : cf SCC V2 : cf SCC V3 : in, fileV3, Tli user Composition Phase SMIOC: Specific Model Input and Output Config. user SCC V1 : Mi -> Mj, Tli, Tnlij V2 : Mi -> Mj, Tij (+ V6) V4 : Mj -> Mk user SCC: Specific Coupling Configuration Driver T Mi Mj MkMk Definition Phase Mi PMIOD V1: out, metadata V1 V2: out, metadata V2 V3: in, metadata V3 Mj PMIOD V1: in, metadata V1 V4: out, metadata V4 Mk PMIOD V4: in, metadata V4 V5: in, metadata V5 fileV6 fileV3 fileV5 PMIOD: Potential Model Input and Output Description Mi: Model i T: Transformer

15. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 15 => Available for beta testers New PRISM System model interface (PSMILe V.0) Using MPI1 or MPI2 and Conforming with final PRISM coupler interface. Direct communication between models with same grid and partitioning Modularity: prism_put and prism_get may be called at each model time step; exchange is performed or not by PSMILe, depending on user’s specifications in namcouple. Automatic time integration by PSMILe depending on user’s specification I/O and combined I/O and coupling functionalities New interpolations / interfacing with SCRIP library: 1st and 2nd order conservative remapping for all grids Bilinear and bicubic interpolation for «logically-rectangular» grids Bilinear and bicubic interpolation for reduced atmospheric grids F90 rewriting (dynamic memory allocation) NetCDF format for grid and restart auxiliary files 5 - PRISM First Coupler: Oasis 3.0

16. Next Generation Climate Models for Advanced High Performance Computing Facilities March 3-5, 2003 Slide 16 Contact us: http://www.enes.org Sophie.valcke@cerfacs.fr Damien.Declat@cerfacs.fr Rene.Redler@ccrl-nece.de Latour@fujitsu.fr Reiner@munich.sgi.com Schoenemey@compuserve.de