1. Uncertainty Analysis & UATools Statistical network March 3rd 2009

2. Outline presentation Why uncertainty analysis? What is it? How to perform an uncertainty analysis? What can I do with the results? Discussion: Do we want UATools? How to arrange further development of UATools?

3. Take a physical model … Model R

4. … with uncertainties in input… Model R

5. … uncertainties in the parameters … Model R

6. … uncertainties in the model structure… Model R

7. … and thus uncertainty about the results. Model R

8. Why uncertainty analysis on models? It suits the character of the modelled processes: variable and uncertain But also: Accuracy of results acceptable? Possible to improve the accuracy? Objectives for further research Estimation of risk of undesired events …

9. Example: Regional watermanagement Noordelijke IJsselvallei (Ruben Dahm)

10. Example: Regional watermanagement

11. Uncertainty analysis in 6 steps: 1.Problem definition 2.Inventory of uncertainties 3.Quantification of uncertainties 4.Identification of main sources of uncertainty 5.Quantification of uncertainty in the model results 6.Interpretation and presentation Tip: Guidance for UA => bulletin\klis

12. Model...... R statistics R R Often necessary: Monte Carlo analysis

13. Model UATools Define uncertainties Batch run Ensemble of output Statistical analysis of output Select values To facilitate UA: UATools

14. Screendump of UATools

15. Example: UA of HBC Waddensea Uncertainty in HBC Water level Wave heigth Wave period water level wave height, period critical crest level => Uncertainty in critical crest level Joost Beckers et al.

16. Set-up UA of HBC Waddensea SWAN calculations in a Monte Carlo setting h( α w ), U w ( α w ) H m0, T m-1,0 Uncertainty of water level Uncertainty of wind speed SWAN model parameters uncertainty SWAN input uncertainty Hydra-K calculations in a Monte Carlo setting uncertainty of SWAN results uncertainty of HBC uncertainty of crest levels 1a1a 2c2c 2a2a 2b2b 1b1b

17. UA Waddensea: Contributions to uncertainty Shallow water locationsDeep water locations Water level statistics Wind speed statistics important at deep water SWAN uncertainty, predominanty depth induced breaking will be less

18. Example: river morphology Delft3D variability of the river bed

19. shipping width at OLR Example: river morphology Delft3D

20. Questions & discussion Do we want UATools? How to arrange further development of UATools?