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A protocol for model validation

ACCENT/GLOREAM Workshop. Paris, France, 11-13 October 2006. A protocol for model validation. Peter Builtjes, TNO-the Netherlands and FU-Berlin. I) Introduction II) A first lay-out of a protocol III) Testing of the protocol IV) Discussion. I) Introduction.

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A protocol for model validation

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  1. ACCENT/GLOREAM Workshop Paris, France, 11-13 October 2006 A protocol for model validation Peter Builtjes, TNO-the Netherlands and FU-Berlin

  2. I) Introduction II) A first lay-out of a protocol III) Testing of the protocol IV) Discussion ACCENT/GLOREAM Workshop - A protocol for model validation

  3. I) Introduction • Model validation/evaluation/testing: comparison between calculated and observed concentrations/depositions • Observed concentrations should be accurate (the instrument) and spatial representative (in balance with the model grid) ACCENT/GLOREAM Workshop - A protocol for model validation

  4. Spatial representative • Ask the expert, rural, Educated guess • Analysis of concentration patterns in time • More stations in one grid • Field study with for example passive samplers • Determination by modelling-data assimilation • For regional scale modelling, using rural stations, +/- 20 % ? ACCENT/GLOREAM Workshop - A protocol for model validation

  5. Recent model intercomparison and validation studies: EUROTRAC, EMEP-review, EURO-DELTA Recommendation: • No model validation for just one model • Combine model intercomparison with model validation ACCENT/GLOREAM Workshop - A protocol for model validation

  6. PM2.5 concentrations over Europe, preliminary/confidential first results EURODELTA ACCENT/GLOREAM Workshop - A protocol for model validation

  7. Carlos Borrego, AIR4EU Total Model Uncertainty = Model uncertainty + Input data uncertainty + Variability Recommended Quality Indicators: • Correlation Coefficient • Fractional Bias • RMSE (RPE) • NMSE ACCENT/GLOREAM Workshop - A protocol for model validation

  8. Model intercomparison and validation • City Delta and Euro Delta: JRC-graphical tool • EMEP model intercomparison: TNO-tool ACCENT/GLOREAM Workshop - A protocol for model validation

  9. Taylor diagram for mean Summer ozone Fine-scale and coarse-scale models ACCENT/GLOREAM Workshop - A protocol for model validation

  10. Compared to EMEP-review ACCENT/GLOREAM Workshop - A protocol for model validation

  11. In TNO: Quick Scan based on EMEP review tool to test different model versions of the LOTOS-EUROS model + input: Required QA/QC ACCENT/GLOREAM Workshop - A protocol for model validation

  12. II) A first lay-out of a protocol Based on discussions at the ACCENT Workshop on Model Benchmarking and Quality AssuranceThessaloniki, 29/30 May 2006 Items of a protocol: a) Define the purpose of the model and of the validation Which output should be validated? Example: Hourly ozone or annual averaged Benzene ACCENT/GLOREAM Workshop - A protocol for model validation

  13. b) Identify the processes required in the model Is aerosol chemistry required or not? c) Define the horizontal and vertical resolution, and the time scale of the output d) Concerning the input data, decide which data should be fixed Example: are emissions taken as they are given? ACCENT/GLOREAM Workshop - A protocol for model validation

  14. e) Concerning observations, decide about QA/QC and spatial representativity d) Quality indicators should be defined, including a threshold below which the model performance will be considered as inadequate For daily max O3, the correlation coefficient between calculated and observed should be more than 0.5, based on previous studies e) Sensitivity runs should be defined for key processes, or key input data ACCENT/GLOREAM Workshop - A protocol for model validation

  15. III) Testing of the protocol An attempt a) Purpose of the validation for O3 daily max Summer, over Europe b) Processes required: Only gasphase chemistry, like EMEP, RADM, CBM4 (box model validation needed, see Poppe 1996) ACCENT/GLOREAM Workshop - A protocol for model validation

  16. c) Horizontal resolution : 25 x 25 km2, or 50 x 50 km2(for discussion!!) Vertical resolution: 20 layers upto the lower stratosphere, or 5 layers upto 5 km (for discussion!!) Time resolution: hourly, not for discussion d) Fixed input data: • Anthropogenic and biogenic emissions • Meteorology, prognostic and diagnostic • Boundary conditions, MOZART/TM5, or Logan • Landuse data base ACCENT/GLOREAM Workshop - A protocol for model validation

  17. e) Observations: EMEP only, rural stationsUncertainty +/- 20 % ??? f) Quality indicators: Based on experience in Euro-Delta/EMEP review g) Sensitivity runs: for example: • Biogenic emissions • Reactivity of anthropogenic VOC-emissions • Cloud cover • Dry deposition, also over sea ACCENT/GLOREAM Workshop - A protocol for model validation

  18. IV) Discussion/Statements Always combine model validation with model intercomparison Make ensemble approach and data assimilation an integral part of model validation Work towards toolkit : JRC + TNO-EMEP review The proposed protocol - seems to work for daymax O3 - should be tested in several projects and by several groups, and based on experience improved upon And finally being “accepted” ACCENT/GLOREAM Workshop - A protocol for model validation

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