1. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH C. DeLuca/NCAR, J. Anderson/NCAR, V. Balaji/GFDL, B. Boville/NCAR, N. Collins/NCAR, T. Craig/NCAR, C. Cruz/GSFC, A. da Silva/GSFC, R. Hallberg/GFDL, C. Hill/MIT, M. Iredell/NCEP, R. Jacob/ANL, P. Jones/LANL, B. Kauffman/NCAR, J. Larson/ANL, J. Michalakes/NCAR, E. Schwab/NCAR, S. Smithline/GFDL, Q. Stout/U Mich, M. Suarez/GSFC, A. Trayanov/GSFC, S. Vasquez/NCAR, J. Wolfe/NCAR, W. Yang/NCEP, M. Young/NCEP and L. Zaslavsky/GSFC Introduction to the Earth System Modeling Framework NSIPP Seasonal Forecast NCAR/LANL CCSM NCEP Forecast GFDL FMS Suite MITgcm NASA GSFC PSAS Climate Data Assimilation Weather

2. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Outline ESMF Overview ESMF Applications Related Projects ESMF Architecture Timeline

3. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Background NASA’s Earth Science Technology Office proposed the creation of an Earth System Modeling Framework (ESMF) in the September 2000 NASA Cooperative Agreement Notice: “Increasing Interoperability and Performance of Grand Challenge Applications in the Earth, Space, Life and Microgravity Sciences” A large, interagency collaboration with roots in the Common Modeling Infrastructure Working Group proposed three interlinked projects to develop and deploy the ESMF, which were all funded: Part I: Core ESMF Development (PI: Killeen, NCAR) Part II: Modeling Applications (PI: Marshall, MIT) Part III: Data Assimilation Applications (PI: da Silva, NASA GMAO)

4. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Motivation In climate research and NWP... increased emphasis on detailed representation of individual physical processes; requires many teams of specialists to contribute components to an overall modeling system In computing technology... increase in hardware and software complexity in high-performance computing, as we shift toward the use of scalable computing architectures In software … development of frameworks, such as FMS, GEMS, CCA and WRF, that encourage software reuse and interoperability The ESMF is a focused community effort to tame the complexity of models and the computing environment. It leverages, unifies and extends existing software frameworks, creating new opportunities for scientific contribution and collaboration.

5. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH ESMF Project Description GOALS: To increase software reuse, interoperability, ease of use and performance portability in climate, weather, and data assimilation applications PRODUCTS: Core framework: Software for coupling geophysical components and utilities for building components Applications: Deployment of the ESMF in 15 of the nation’s leading climate and weather models, assembly of 8 new science-motivated applications METRICS: RESOURCES and TIMELINE: $9.8M over 3 years ReuseInteroperabilityEase of AdoptionPerformance 15 applications use ESMF component coupling services and 3+ utilities 8 new applications comprised of never- before coupled components 2 codes adopt ESMF with < 2% lines of code changed, or within 120 FTE-hours No more than 10% overhead in time to solution, no degradation in scaling

6. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH ESMF Accelerates Advances in Earth System Science Eliminates software barriers to collaboration among organizations Easy exchange of model components accelerates progress in NWP and climate modeling Independently developed models and data assimilation methods can be combined and tested Coupled model development becomes a truly distributed process Advances from smaller academic groups easily adopted by large modeling centers Facilitates development of new interdisciplinary collaborations Simplifies extension of climate models to upper atmosphere Accelerates inclusion of advanced biogeochemical components into climate models Develops clear path for many other communities to use, improve, and extend climate models Many new model components gain easy access to power of data assimilation

7. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH ESMF Collaborators NSF NCAR Tim Killeen, PI Jeff Anderson Byron Boville Nancy Collins Cecelia DeLuca Roberta Johnson Al Kellie John Michalakes David Neckels Earl Schwab Robbie Staufer Silverio Vasquez Jon Wolfe DOE ANL Rob Jacob Jay Larson NOAA GFDL Ants Leetmaa V. Balaji Robert Hallberg Shep Smithline NASA GMAO Arlindo da Silva, PI Michele Rienecker Max Suarez Atanas Trayanov Christian Keppenne Leonid Zaslavsky Will Sawyer Carlos Cruz NOAA NCEP Stephen Lord Mark Iredell Mike Young Weiyu Yang John Derber MIT John Marshall, PI Chris Hill DOE LANL Phil Jones University of Michigan Quentin Stout

8. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Outline ESMF Overview ESMF Applications Related Projects ESMF Architecture Timeline

9. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Modeling Applications SOURCEAPPLICATION GFDLFMS B-grid atmosphere at N45L18 FMS spectral atmosphere at T63L18 FMS MOM4 ocean model at 2°x2°xL40 FMS HIM isopycnal C-language ocean model at 1/6°x1/6°L22 MITMITgcm coupled atmosphere/ocean at 2.8°x2.8°, atmosphere L5, ocean L15 MITgcm regional and global ocean at 15kmL30 GMAO/NSIPPNSIPP atmospheric GCM at 2°x2.5°xL34 coupled with NSIPP ocean GCM at 2/3°x1.25°L20 NCAR/LANLCCSM2 including CAM with Eulerian spectral dynamics and CLM at T42L26 coupled with POP ocean and data ice model at 1°x1°L40

10. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Data Assimilation Applications SOURCEAPPLICATION GMAO/DAOPSAS interface layer with 2O0K observations/day CAM with finite volume dynamics at 2°x2.5°L55, including CLM NCEPGlobal atmospheric spectral model at T170L42 SSI analysis system with 250K observations/day, 2 tracers WRF regional atmospheric model at 22km resolution CONUS forecast 345x569L50 GMAO/NSIPPODAS with OI analysis system at 1.25°x1.25°L20 resolution with ~10K observations/day MITMITgcm 2.8° century / millennium adjoint sensitivity

11. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Interoperability Experiments: 8 New Applications COUPLED CONFIGURATIONNEW SCIENCE ENABLED GFDL B-grid atm / MITgcm ocnGlobal biogeochemistry (CO2, O2), SI timescales. GFDL MOM4 / NCEP forecastNCEP seasonal forecasting system. NSIPP ocean / LANL CICESea ice model for extension of SI system to centennial time scales. NSIPP atm / DAO analysisAssimilated initial state for SI. DAO analysis / NCEP modelIntercomparison of systems for NASA/NOAA joint center for satellite data assimilation. DAO CAM-fv / NCEP analysisIntercomparison of systems for NASA/NOAA joint center for satellite data assimilation. NCAR CAM Eul / MITgcm ocnImproved climate predictive capability: climate sensitivity to large component interchange, optimized initial conditions. NCEP WRF / GFDL MOM4Development of hurricane prediction capability.

12. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Outline ESMF Overview ESMF Applications Related Projects ESMF Architecture Timeline

13. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Related Projects PRISM is an ongoing European Earth system modeling infrastructure project Involves current state-of-the-art atmosphere, ocean, sea-ice, atmospheric chemistry, land- surface and ocean-biogeochemistry models 22 partners: leading climate researchers and computer vendors, includes MPI, KNMI, UK Met Office, CERFACS, ECMWF, DMI ESMF is working with PRISM to merge frameworks and develop common conventions CCA is creating a minimal interface and sets of tools for linking high performance components. CCA can be used to implement frameworks and standards developed in specific domains (such as ESMF). Collaborators include LANL, ANL, LLNL, ORNL, Sandia, University of Tennessee, and many more. Ongoing ESMF collaboration with CCA/LANL on language interoperability. Working prototype demonstrating CCA/ESMF interoperability, to be presented at SC2003. For joint use with PRISM, ESMF developed a component database to store component import/export fields and component descriptions For joint use with PRISM, ESMF developed a component database to store component import/export fields and component descriptions

14. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH ESMF Connections Larson/ANL DeLuca/NCAR-SCD Jones/LANL Stout/U Mich Killeen/NCAR Drake/ORNL Boville/NCAR-CGD Michalakes/NCAR-MMM Suarez/NASA Goddard Balaji/NOAA GFDL CCA WRF SciDAC CCSM GEMSFMS SWMF PRISM ESMF ESMF Earth System Modeling Framework CCA DOE Common Component Architecture SciDAC DOE/NSF CCSM SciDAC Project GEMS Goddard Earth Modeling System FMS GFDL Flexible Modeling System SWMF Space Weather Modeling Framework WRF Weather Research and Forecast Model CCSM Community Climate System Model PRISM Program for Int. Earth System Modeling

15. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Outline ESMF Overview ESMF Applications Related Projects ESMF Architecture Timeline

16. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Computational Characteristics of Weather/Climate Mix of global transforms and local communications Load balancing for diurnal cycle, event (e.g. storm) tracking Applications typically require 10s of GFLOPS, 100s of PEs – but can go to 10s of TFLOPS, 1000s of PEs Required Unix/Linux platforms span laptop to Earth Simulator Multi-component applications: component hierarchies, ensembles, and exchanges Data and grid transformations between components Applications may be MPMD/SPMD, concurrent/sequential, combinations Parallelization via MPI, OpenMP, shmem, combinations Large applications (typically 100,000+ lines of source code) Platforms assim sea ice ocean land atm physicsdycore assim_atm atmland Seasonal Forecast coupler

17. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Architecture Low Level Utilities Fields and Grids Layer Model Layer Components Layer: Gridded Components Coupler Components ESMF Infrastructure User Code ESMF Superstructure BLAS, MPI, NetCDF, … External Libraries 1.ESMF provides an environment for assembling geophysical components into applications. 2.ESMF provides a toolkit that components use to i.increase interoperability ii.improve performance portability iii.abstract common services Becoming an ESMF Component Pack model import and export data into ESMF data structures and conform to a standard calendar. Use ESMF utilities internally as desired. Organize model using standard ESMF methods: Initialize, Run, Finalize, ReadRestart, WriteRestart. Methods may be multi-phase (Run phase=1, Run phase=2). Method interfaces are prescribed. Instantiate an ESMF Component with name, type, config information. Register standard model methods with Component. If desired, register data. Use ESMF AppDriver to sequence and run Components.

18. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Design Features ESMF enables modeling applications to be: Scalable Models are built from modular components, and can be easily nested within larger applications Performance - portable ESMF high-performance communication libraries offer a consistent interface across computer architectures Exchangeable Standard component interfaces enable interoperability

19. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH ESMF Class Structure DELayout Communications State Data imported or exported Bundle Collection of fields GridComp Land, ocean, atm, … model F90 Superstructure Infrastructure Field Physical field, e.g. pressure Grid LogRect, Unstruct, etc. Data Communications C++ Regrid Computes interp weights CplComp Xfers between GridComps Utilities Machine, TimeMgr, LogErr, I/O, Config, Base etc. Array Hybrid F90/C++ arrays Route Stores comm paths DistGrid Grid decomposition PhysGrid Math description

20. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Design Principle: Local Communication All inter-Component communication within ESMF is local - all communication is handled within Components. This allows the architecture of the framework to be independent of the communication strategy. climate_comp ocn_comp atm_comp atm_phys phys2dyn_coupler atm_dyn PE atm2ocn _coupler As a consequence, Coupler Components must be defined on the union of the PEs of all the Components that they couple. In this example, in order to send data from the atmosphere Component to the ocean, the atm2ocn Coupler mediates the send.

21. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Design Principle: Scalable Applications Since each ESMF application is also a Component, entire ESMF applications can be treated as Gridded Components and nested within larger applications. climate_comp ocn_comp atm_comp ocn2atm_coupler atm_phys phys2dyn_coupler atm_dyn PE Example: atmospheric application itself composed of multiple Components may be run standalone, or nested within a larger climate application

22. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Design Principle: Modularity Gridded Components don’t have access to the internals of other Gridded Components, and don’t store any coupling information. Gridded Components may: pass their States to other Components through their argument list or receive user-defined methods through their argument list for transforming and transferring States. These are called Transforms, and they contain a function pointer and attributes describing frequency and validity criteria. Transforms may modify the data in States, receive States from other Components, send States to other Components, etc. ! From climate comp call ESMF_CompRun(atm, atm_xform) call ESMF_CompRun(ocn, ocn_xform) ! From atm comp call ESMF_StateXform(atm_ex_state, & atm_xform) ! From ocn comp call ESMF_StateXform(ocn_im_state, & ocn_xform) EX 1: One-way coupling from atm to ocn atm_xform is a send; ocn_xform a receive EX 2: Standalone atm atm_xform is a no-op ! From atm comp call ESMF_CompRun(ocn, ocn_xform) call ESMF_StateXform(atm_ex_state, & atm_xform)

23. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Design Principle: Uniform Communication API The same programming interface is used for shared memory, distributed memory, and combinations thereof. Machine model = abstraction of machine architecture (num_nodes, num_pes_per_node, etc.) DE = a decomposition element - may be virtual, thread, MPI process DELayout = an arrangement of DEs, in which dimensions requiring faster communication may be specified and resources arranged accordingly DELayout: 4 x 3, ESMF_COMM_SHR in x and ESMF_COMM_MP in y The data in a Grid is decomposed according to the number and topology of DEs in the DELayout Performance of ESMF AllGather vs. raw MPI

24. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Outline ESMF Overview ESMF Applications Related Projects ESMF Architecture Timeline

25. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH Time Line May 2002Draft Developer’s Guide and Requirements Document completed 1 st Community Requirements Meeting and review held in D.C. July 2002ESMF VAlidation (EVA) suite assembled August 2002Architecture Document: major classes and their relationships Implementation Report: language strategy and programming model Software Build and Test Plan: sequencing and validation May 2003ESMF Version 1.0 release, 2 nd Community Meeting at GFDL November 2003First 3 interoperability experiments completed April 2004Second API and production software release, 3 rd Community Meeting November 2004All interoperability experiments complete; all testbed applications compliant January 2005Final delivery of source code and documentation

26. NSF NCAR / NASA GSFC / DOE LANL ANL / NOAA NCEP GFDL / MIT / U MICH More Information ESMF website: http://www.esmf.ucar.edu Acknowledgements The ESMF is sponsored by the NASA Goddard Earth Science Technology Office.