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C-Coupler1: a Chinese community coupler for Earth system modeling Li Liu, Cheng Zhang, Ruizhe Li, Guangwen Yang, Bin Wang, Zhiyuan Zhang Tsinghua University,

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Presentation on theme: "C-Coupler1: a Chinese community coupler for Earth system modeling Li Liu, Cheng Zhang, Ruizhe Li, Guangwen Yang, Bin Wang, Zhiyuan Zhang Tsinghua University,"— Presentation transcript:

1 C-Coupler1: a Chinese community coupler for Earth system modeling Li Liu, Cheng Zhang, Ruizhe Li, Guangwen Yang, Bin Wang, Zhiyuan Zhang Tsinghua University, China liuli-cess@tsinghua.edu.cn http://c-coupler.org/index.action 1

2 Outline C-Coupler development C-Coupler1 Bitwise identical reproducibility Future work 2

3 Milestones of C-Coupler development 3 MilestonesTime Initiation2010.01 Main design and software design2010.10 Prototype system of C-Coupler2011.07 Common multi-dimensional remapping software CoR2012.07 Prototype system of C-Coupler platform2012.12 Early release of C-Coupler1 (beta version) and FGOALS-gc2013.09 Parallel 3-D coupling2013.10 Enhancement for bitwise identical reproducibility on the C- Coupler platform 2013.12 Release of C-Coupler12014.06

4 Target functions of C-Coupler Science  Flux computation  3-D coupling  Two-way model nesting and interactive ensemble Technology  Modularization, extendibility  High parallel efficiency Application  Powerful coupling functions, user friendliness  Reliability, automatic error detection  Reproducibility of simulation results 4

5 Architecture of models with C-Coupler ATMICE LNDOCN Coupler component C-Coupler 5

6 Interfaces Process MGRCommunication MGR Grid MGRRemapping MGR Restart MGRDecomposition MGR Time MGRData MGR External coupling algorithms Remapping algorithms Scientific algorithms I/O algorithms C-Coupler runtime software system Standardized component models Component models code ATMsOCNsLNDsICEsCarbon … Component models configuration Coupled models configuration Coupling flow configuration Coupling generator Runtime configuration Coupling generator Configuration system Runtime software system Software structure of C-Coupler 6

7 Software modules Standardized component models External algorithms Runtime configuration files of experiment models C-Coupler Create case From a default settingFrom an existing setting Input data Configure Initial or restartOutput settingsStart and stop time NamelistParallel settingsCompiling options Compile Experimental setting package Output data Run case

8 Outline C-Coupler development C-Coupler1 Bitwise identical reproducibility Future work 8

9 C-Coupler1 C-Coupler runtime software system for 3-D coupling (in C++) – CoR1.0: A common multi-dimensional remapping software for remapping, grid and field data management – Coupling interfaces (Fortran and C++) – Function managers, e.g., time manager, communication manager, etc. – Parallelization C-Coupler platform: a runtime environment for model development, simulation and reproducibility Runtime configuration for the CPL6 coupling flow Imported: CPL6 flux algorithms 9

10 Metadata for runtime configuration Timer – Field instance – 10

11 Metadata for runtime configuration External algorithm 11

12 Metadata for runtime configuration runtime algorithm list Runtime procedure 12

13 Data transfer and interpolation Data transfer – All fields (of different data types, on different grids, on different parallel decompositions, or with different dimensions) to be transferred at the current time step can be packed into one message 3-D interpolation – 2-D+1-D implementation Spline is supported for 1-D interpolation – Offline and online – Parallel dynamic 3-D interpolation now (for example, for coupling between AGCM and atmospheric chemistry model) 13

14 Example: parallel 2D flux coupling, global coupling, climate system model GAMIL2LICOM2 CLM3 CICE4_ LASG C-Coupler1 14 FGOALS-gc

15 Coupler component in FGOALS-gc 15

16 Example: Sharing platform for GAMIL development 16 GAMIL CLM2 FGOALS-gc FGOALS-gc-colm CLM3 CoLM CLM4 GEOS-Chem C-Coupler platform …

17 WRF MASNUM- Wav POM C-Coupler Example: parallel 3-D coupling, regional coupling, direct coupling 3-D coupling: Four choices for 1D interpolation for vertical level 2D coupling Direct coupling 2D coupling

18 Example: model integration 18 Integrating a standalone model versions, e.g., CESM1.2.1, CESM1.0.5, WRF and MOM4p1, onto the C-Coupler platform – Several configuration files – Less than 10 lines of source code in the main driver – Enhancement for bitwise-identical reproducibility to the simulations

19 Outline C-Coupler development C-Coupler1 Bitwise identical reproducibility Future work 19

20 Reproducibility A fundamental principle of scientific research More and more claims for reproducibility of published results – Nature family, Science and Geoscientific Model Development, etc. 20

21 Bitwise identical reproducibility? It may be unnecessary, because climate simulations results are generally statistical characteristics of output data on time scales longer than a few months It was extremely difficult to achieve bitwise identical reproducibility – The whole simulation setting needs to be recorded and recovered Existing works show that climate simulation results can be sensitive to round-off error 21

22 Experimental setups Two fully coupled models: CESM1 and FGOALS-g2 CMIP5 historical experiments: 60 years (1850-1909) 22 Model Simulation cases #1#2#3#4 CESM1 11.1_120_C111.1_128_C111.1_128_C212.1.3_128_C1 FGOALS-g2 11.1_104_C111.1_108_C111.1_108_C212.1.3_108_C1 ModelLabel Number of processes ATMOCNLNDICECPLGLC CESM1 120 128 FGOALS-g2 1043018242012- 1083018242016- ModelLabelCompiling option CESM1 C1-O2 -convert big_endian -assume byterecl -ftz -FR -fp-model precise C2-O2 -convert big_endian -assume byterecl -ftz -FR FGOAL S-g2 C1 -c -r8 -i4 -O2 -zero -132 -convert big_endian -assume byterecl -no-vec -mp1 -fp- model precise -fp-speculation=safe C2-c -r8 -i4 -O2 -zero -132 -convert big_endian -assume byterecl

23 Climatological mean TS by CESM1 23

24 Climatological mean TS by FGOALS-g2 24 Bitwise identical reproducibility is important to Earth system modeling Current status of bitwise identical reproducibility of published results?

25 Design of a survey: 17 journals 25 Climate DynamicsGeophysical Research Letters Geoscientific Model DevelopmentGlobal and Planetary Change Global Biogeochemical CyclesJournal of Advances in Modelling Earth Systems Journal of ClimateJournal of Geophysical Research: Atmospheres Journal of HydrologyJournal of Physical Oceanography Journal of the Atmospheric SciencesMonthly Weather Review NatureNature Climate Change Nature GeoscienceProceedings of the National Academy of Sciences of the United States of America Quarterly Journal of the Royal Meteorological Society

26 Statistical characteristics of paper selection 26 Year of publishing 200620072008200920102011201220132014 Number of citations ≥10≥9≥8≥7≥5≥4≥3≥1≥0 Number of selected papers 35 42414245484617 Average number of citations per paper 92.174.565.952.626.031.820.45.10.4

27 Results of the survey No reply: 283 papers (80.6%) – No corresponding authors: 5 papers (1.4%) – Automatic email rejection: 66 papers (18.8%) – No active reply: 212 papers (60.4%) Replied without required information: 54 papers (15.4%) – Replied without required information and confirmation: 7 papers (2%) – Inconvenient for reproduction: 47 papers (13.4%) Unsuccessful re-run: 4 papers (1.1%) Successful re-run: 5 papers (1.4%) Successful bitwise identical reproduction: 5 papers (1.4%) 27

28 Brief summary Fellow scientists heavily depend on the authors’ help to reproduce the published simulation results It is always inconvenient even impossible to recreate the same simulation setting as the whole simulation setting is rarely kept for a long time The authors still have to spend a lot of efforts to help the fellow scientists who want to reproduce these results, even when the whole simulation setting can be recalled 28 Bitwise identical reproducibility of Earth system modeling is currently at a very low level

29 29 Experimental setup package for technical reproducibility GIT server and code version id for each component model Reproducibility for model code Code patch for each component model SVN server and version id for each input data file Reproducibility for input data Check sum of each input data file Reproducibility for input parameters Script for generating the input parameter files of each component model Reproducibility for parallel settings Configuration file with the parallel settings of all component models Reproducibility for Compiler and compiling options Configuration file of compiling options of each component model Information of compiler for each component model Reproducibility for computer system Name of the computer system Log information for configuring Username, computer name and configuration time, and error and warning report for configuration Log files for technical reproducibility Log files for compiling Log files for the execution of model simulation Output files for technical reproducibility Name of model version Description of model simulation Time of the corresponding configuration C-Coupler platform Configure Compile and run

30 Flowchart for achieving bitwise identical reproducibility on the C-Coupler platform 30

31 An example 31

32 Worldwide standard of bitwise identical reproducibility Any fellow scientists can independently obtain the whole simulation setting of published results and then can independently reproduce exactly the same simulation output Requires scientists’ actions, journals’ actions, model intercomparison projects’ actions, and technical supports. 32

33 A framework for achieving worldwide bitwise identical reproducibility 33

34 Outline C-Coupler development C-Coupler1 Bitwise identical reproducibility Future work 34

35 Future work Coupling generator Parallel optimization Testing bed with benchmarks ASCII configuration file format  XML format More coupling functions 35

36 Thank you 36

37 Example: Computation performance 37 Time for a data transfer (low resolution)

38 Example: Computation performance 38 Time for an interpolation (low resolution)


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