1. Climate Modelling for Ireland Ray McGrath, Met Éireann EPA Climate Change Conference, 30 June 2010, Aviva Stadium, Dublin

6. Average number of days per month with ground frost (1961-1990) ‏ EU ENSEMBLES Project – European Climate (2004 – 2009) ‏ ENSEMBLES : EU FP6-funded project involving 66 institutes (including Met Éireann) from 20 countries. Goal: Run ensembles of different climate models to sample uncertainties Assess reliability of models for historical periods Working towards a probabilistic framework for projections of climate change Focus: season, decadal, centennial; global, regional and local. Applications of societal relevance ENSEMBLES has produced ~25 regional climate simulation datasets for Europe; also 7 global simulations.

7. EU ENSEMBLES Project – European Climate (Sep 2004 – Dec 2009) ‏ C4I contribution: 2 centennial simulations over Europe

8. EU ENSEMBLES Project – European Climate (Sep 2004 – Dec 2009) ‏ Source: van der Linden P., and J.F.B. Mitchell (eds.) 2009: ENEMBLES: Climate Change and its Impacts: Summary of research and results from the ENSEMBLES project.

9. Flood or drought? Change in river Suck discharge: 2021-2060 relative to 1961-2000. Based on 13 ENSEMBLES simulations. EU ENSEMBLES Project: local applications

10. ENSEMBLES/C4I: expected change (%) in seasonal rainfall 2021-2050 compared with 1961-1990 (mean of 20 climate model simulations) Winter Spring Summer Autumn But large spread between the simulations… too much uncertainty

11. ENSEMBLES/C4I RCM simulations have highlighted the uncertainty in precipitation forecasts. Example: expected winter change (%) 2021-2050 compared with 1961-1990 20 member ensemble 12 member ensemble Spread reflects model differences. GHG emission uncertainty is not included (same in all simulations) .

12. ENSEMBLES: expected change (%) in seasonal rainfall 2071-2100 compared with 1961-1990 (mean of 12 climate model simulations) Winter Spring Summer Autumn

14. In 2007 Met Éireann /ICHEC / UCD became partners in EC-Earth , a consortium of European Weather Services and Institutes (~23 in total) established to develop and use a common global Earth System Model: atmosphere, ocean/sea-ice, land, atmospheric chemistry, Carbon cycle – unified within a single package. EC-Earth modelling work will feed into the next IPCC Assessment Report Climate modelling in Met Éireann: moving to the global scale

16. Joint EC-Earth and ECMWF seasonal forecast components Planned EC-Earth components For CMIP5: T159L62, 1 deg Ocean On 6 platforms OASIS Atmosphere GCM: IFS Ocean GCM: NEMO Sea-ice:LIM2/3 Land: IFS H-tessel Atmospheric Chemistry and aerosols: TM5 Vegetation: LPJ Marine ecosystem: PISCES New EC-Earth components

17. Timeline Testing/tuning –> Spin-up runs –> CMIP5 runs An ensemble of simulations planned – distributed among partners Test phase Historical run + Initialized Decadal hindcasts ~900 yrs 1850 2005 Pre-industrial Spin-up 2 independent simulations by Met É ireann / ICHEC and DMI/KNMI. RCP runs 2100

21. Irish partner ICHEC: Designated Earth System Grid ‘Data Node’ through e-INIS (the Irish National e-Infrastructure) PCMDI - Program for Climate Model Diagnosis and Intercomparison BADC - British Atmospheric Data Centre ICHEC – Irish Centre for High-End Computing ICHEC

25. EC-Earth spin-up event: change in the meridional overturning circulation (MOC) after ~500 years and recovery SST Anomaly during MOC decrease Cold spell lasted ~50 years, lagged MOC decline by ~20 years… An unforced event simulated by the model (no influx of fresh water into the N. Atlantic, etc.)

26. EC-Earth spin-up event: changes in the average SST (anomalies) over the Atlantic SST oscillations ~40 year cycle – similar to observed Atlantic Multidecadal Oscillation. Cold dip an echo of 8.2kyr event in Holocene? Relative year

27. Data source: http://www.ncdc.noaa.gov/paleo/pubs/alley2000/alley2000.htm 8.2kyr cold event Central Greenland reconstructed temperature 8.2kyr event linked with drainage of glacial lake into N. Atlantic… but may be simply ‘natural variability’ as seen in EC-Earth simulation

28. Regional models not neglected: coupled atmosphere-ocean regional climate model (RCA_NEMO) developed System evaluated by simulating climate over the above area 1961-1990 and comparing against ERA-40 reanalysis data.

31. Future Plans EC-Earth outputs (particularly the decadal simulations) will be used to investigate changes in weather extremes e.g. rainfall. Selected outputs downscaled to 2-5km grid. Outputs will be freely available to drive applications to study local impacts of climate change (flooding, storm surge, coastal erosion, renewable energy – wind/wave, agriculture, forestry,… Empirical Orthogonal Function (EOF) analysis of annual Irish rainfall (1941-2009). The time evolution of the Principle Component for the first mode is shown with a 5-year running trend line. Where is the climate heading?