1. From Climate Data to Adaptation Large-ensemble GCM Information and an Operational Policy-Support Model Mark New Ana Lopez, Fai Fung, Milena Cuellar Funded by Tyndall and Environment Agency

2. Adaptation Challenges 1.Uncertainty in climate information 2.Interactions with other uncertain changes 3.Integrated assessment

3. Wimbleball Water Resource Zone

4. Route Map Large ensemble climate data River flow ensemble Water resource system modelling

5. Large GCM Ensemble: CPdN Explore model uncertainty by varying settings of poorly constrained model parameters HADCM3L model: standard atmosphere & low resolution ocean. 26 perturbed parameters (radiation, large scale cloud formation, ocean circulation, sulphate cycle, sea ice formation and energy convection) Initial condition ensembles. Transient runs: –1920-2000 forced with historical CO 2, solar and volcanic forcing. –2000-2080 forced with different possible scenarios

6. First 246 Completed Simulations IPCC 4AR models CPDN model runs Global Mean Temperature: SRES A2 Anomaly from 1961-1990

7. Data Available 10-year seasonal mean fields Monthly mean (time series): –Large regions (Giorgi) –Selected grid-boxes (including UK) Variables include –Total precipitation rate –Convective cloud amount –Surface air temperature (1.5m) –Relative humidity (1.5m)

8. Modelling Set-up Downscale climate in space and time –SW England -> River Exe –Monthly -> Daily Generate ensemble of daily river flows –CATCHMOD rainfall-runoff model Run flow-ensemble through water resource model

9. Downscaling: Precipitation Gamma transform method –Remove GCM monthly biases –Select daily values from observations August 1930-1985 Frequency Monthly Precip (mm/d) Model Observed August 2020-2060 Frequency Monthly Precip (mm/d) Model Observed

10. Downscaling: Precipitation

11. Downscaling: PET Calculate GCM PET from –Temperature, RH & cloud-cover (radiation) –Adjust for climatological bias –No daily downscaling

12. Downscaling: PET

13. River Flows

14. Month % Change Mean Flow Change: 2020-2039 from 1961-1990

15. Wimbleball Water Resource Model Supplies: –Somerset & Devon (Exeter, Tiverton) River & reservoir dominated 50 ML/d Groundwater Lancmod WR model

16. Wimbleball Reservoir: Historic Monthly Storage, 1930-2005 Month Storage (Ml x 10 4 )

17. Wimbleball Reservoir: 2040 Ensemble Monthly Storage, 2040 Month Storage (Ml x 10 4 )

18. Wimbleball Reservoir: Changing Risk September Storage Year Storage (Ml x 10 4 )

19. Failure to Meet Demand Devon Demand Failure Year No. Simulations

20. Failure to Meet Demand Devon Demand Failure No. Simulations Year Ave. Shortfall

21. Outstanding Issues / Future Work Biases in runoff simulations Simplistic downscaling Higher multiple year failures in simulations Scenarios / ensembles of changing demand Incorporating adaptation options Staged methodology Relative likelihoods Comparison with UKCIP08 / ENSEMBLES