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Climate Modelling for Ireland -Dr Ray McGrath, Met Eireann


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Climate Modelling for Ireland -Dr Ray McGrath, Met Eireann

  1. 1. Climate Modelling for Ireland Ray McGrath, Met Éireann EPA Climate Change Conference, 30 June 2010, Aviva Stadium, Dublin
  2. 2. Outline <ul><li>Brief history of climate modelling in Met Éireann. </li></ul><ul><li>Move from Regional to Global modelling </li></ul><ul><li>Current modelling work and future plans. </li></ul>
  3. 3. History <ul><li>Met É ireann monitors the Irish climate – maintains a network of observing stations. </li></ul><ul><li>Climate & Observations Division analyses historical data and regularly issues reports on case studies, trends in the climate, etc. </li></ul><ul><li>Involved in Numerical Weather Prediction (NWP) for many decades – models used to produce our operational weather forecasts. </li></ul><ul><li>Climate modelling, in spite of synergy with NWP, arrived late… </li></ul>
  4. 4. History <ul><li>Community Climate Change Consortium for Ireland (C4I) project launched in 2003. </li></ul><ul><li>Externally funded (EPA, SEAI, HEA/CosmoGrid) the joint Met Éireann /UCD project focused on Regional Climate Modelling . </li></ul><ul><li>Finished in 2007. </li></ul><ul><li>Provided future scenarios (changes in mean climate, extremes, flooding, waves, storm surge). </li></ul>
  5. 5. History <ul><li>Impact of C4I project </li></ul><ul><li>Climate modelling/research became a core activity for Met Éireann - National Climate Change Strategy (2007-2012). </li></ul><ul><li>Partner in ENSEMBLES project (2004-2009). </li></ul><ul><li>EPA Fellowships (2007- ): weather extremes (analysis of Irish precipitation); new coupled atmosphere/ocean Regional Climate Model developed; air quality modelling. </li></ul>
  6. 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. 7. EU ENSEMBLES Project – European Climate (Sep 2004 – Dec 2009) ‏ C4I contribution: 2 centennial simulations over Europe
  8. 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. 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. 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. 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. 12. ENSEMBLES: expected change (%) in seasonal rainfall 2071-2100 compared with 1961-1990 (mean of 12 climate model simulations) Winter Spring Summer Autumn
  13. 13. Lessons learned from C4I/ENSEMBLES <ul><li>Regional climate modelling introduces additional uncertainty – errors in GCMs compounded with errors in RCM models. </li></ul><ul><li>Local model cannot “correct” fundamental GCM errors. </li></ul><ul><li>Logistical difficulties in accessing GCM outputs (at required spatial/temporal resolution) for downscaling </li></ul><ul><li>Solution: move to a GCM </li></ul><ul><li>Still need RCM for local downscaling – not (yet!) feasible to run GCM at sufficient resolution to model local effects. </li></ul><ul><li>Running own GCM provides autonomy/flexibility in designing experiments. </li></ul>
  14. 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
  15. 15. <ul><li>Consortium influenced by concept of ‘seamless prediction’ in operational weather forecasting - same physical principles (but different processes acting on different scales) for weather and climate. </li></ul><ul><li>merging of capability in short-range, seasonal and climate (decadal/centennial) forecasting areas i.e. single system. </li></ul><ul><li>System based on the ECMWF seasonal prediction system – strong synergy with operational forecasting system in Met É ireann </li></ul>Background to EC-Earth
  16. 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. 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
  18. 18. CMIP5 - Coupled Model Intercomparison Project Phase 5 <ul><li>Outputs from EC-Earth (~50 terabytes of core data) will be delivered to CMPI5 for assessment by IPCC </li></ul><ul><li>CMIP is a standard experimental protocol for studying the output of coupled ocean-atmosphere general circulation models (GCMs) … in support of climate model diagnosis, validation, intercomparison, documentation and data access. </li></ul><ul><li>The purpose… is to address outstanding scientific questions that arose as part of the IPCC/AR4 … and to provide estimates of future climate change. </li></ul>
  19. 19. CMIP5 - Coupled Model Intercomparison Project Phase 5 <ul><li>CMIP5 Goals: </li></ul><ul><li>Evaluate realism of the models. </li></ul><ul><li>Provide projections of future climate change on two time scales, “near term” (out to about 2035) and “long term” (out to 2100+) </li></ul><ul><li>Understand some of the factors responsible for differences in model projections, including quantifying some key feedbacks such as those involving clouds and the carbon cycle. </li></ul>“ Long-Term” (century & longer, 2100/2300) TIER 1 TIER 2 CORE “ realistic” diagnostic “ Near-Term” (decadal) (initialized ocean state) prediction & predictability CORE TIER 1
  20. 20. CMIP5 - Coupled Model Intercomparison Project Phase 5 <ul><li>CMIP5 Schedule: </li></ul><ul><li>July 2010: First model output is expected to be available for analysis. </li></ul><ul><li>July 31, 2012: By this date papers must be submitted for publication to be eligible for assessment by WG1. </li></ul><ul><li>March 15, 2013 : By this date papers cited by WG1 must be published or accepted. </li></ul><ul><li>The IPCC’s AR5 is scheduled to be published in September 2013 . </li></ul>
  21. 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
  22. 22. Met É ireann / ICHEC schedule of EC-Earth simulations: CMIP5 Commitment <ul><li>900 year spin-up of coupled atmosphere/ocean model (pre-Industrial GHG) ~ completed. </li></ul><ul><li>Provides different launch points (700, 725… 825 years) for Industrial run (1850-2005) with prescribed GHG and aerosols for EC-Earth partners. </li></ul><ul><li>Future runs (2006-2100): </li></ul><ul><li>3 x simulations with prescribed GHG and aerosols. </li></ul><ul><li>Decadal simulations (atmosphere only with initialised ocean): </li></ul><ul><li>10/30-year simulations from 1960, 1965,…2005 launch points. </li></ul><ul><li>30-year simulations from 1960, 1980, 2005 launch points. </li></ul>
  23. 23. Met É ireann / ICHEC schedule of EC-Earth simulations for local use <ul><li>High-resolution decadal simulations (atmosphere only) from initialised ocean analysis: </li></ul><ul><li>1990-2010 </li></ul><ul><li>2010-2030 </li></ul><ul><li>Target horizontal resolution ~25km with either 1° or 0.25° ocean (depending on computer resources). </li></ul>How Ireland/UK elevations “appear” on the 25km global EC-Earth grid
  24. 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.)
  25. 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
  26. 27. Data source: 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
  27. 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.
  28. 29. <ul><li>First step in building an integrated system to complement the EC-EARTH GCM </li></ul><ul><li>Will upgrade to next generation Harmonie atmospheric model (non-hydrostatic model): </li></ul><ul><li>HARMONIE will be implemented for operational forecasting in Met Éireann in 2010. </li></ul><ul><li>Model has strong synergy with ECMWF IFS model ‏ (e.g. common physics modules with EC-EARTH). </li></ul><ul><li>Feedback between operational (day-to-day) regional forecasting and climate modelling will enhance development. </li></ul>Coupled atmosphere-ocean regional climate model
  29. 30. Greenland 5 km DEM, Ice Thickness, and Bedrock Elevation Grids <ul><li>EC-Earth used to investigate </li></ul><ul><li>Impact of declining Arctic sea ice cover on climate </li></ul><ul><li>Dynamical impact of declining Greenland ice sheet (reduced to bedrock). </li></ul><ul><li>Sensitivity of atmospheric ‘blocking’ to model horizontal resolution </li></ul>
  30. 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?
  31. 32. Acknowledgements <ul><li>Tido Semmler (Met É ireann) </li></ul><ul><li>Emily Gleeson (Met É ireann) </li></ul><ul><li>Alastair McKinstry (ICHEC) </li></ul><ul><li>Shiyu Wang (ICHEC/Met É ireann– EPA Fellowship) </li></ul><ul><li>Seamus Walsh (Met É ireann) </li></ul>