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Variability and Extremes in the CRCM

Variability and Extremes in the CRCM. Hélène Côté and Daniel Caya Climate Simulations Group Consortium Ouranos. Development of Scenarios of Climate Variability and Extremes: Current Status and Next Steps Victoria, 16-17 October 2003. Outline. Current status of CRCM

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Variability and Extremes in the CRCM

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  1. Variability and Extremes in the CRCM Hélène Côté and Daniel Caya Climate Simulations Group Consortium Ouranos Development of Scenarios of Climate Variability and Extremes: Current Status and Next Steps Victoria, 16-17 October 2003

  2. Outline • Current status of CRCM • Policy Run II vs Policy Run III • Production runs with version 3.6.1 • Preliminary results (the first 5 years of the 25-year run) • Next operational version: CRCM 3.6.3 • Development of CRCM 4.0 • Variability issues in regional climate modelling • Modelling the extremes • The data we have • What we plan to do • Validation issues • How to improve the model

  3. From Policy Run II to Policy Run III 3.5.1 vs 3.6.1

  4. 45 km grid point spacing 193 x 145 grid points 29 vertical levels Lid: 30 km Archival : every 6 hours (pcp every timestep) Transient CO2 Spinup period: 2 years Approx. 1 month CPU time per simulated year …. 5.7Gb of model outputs per simulated month…. Current Simulations Configuration Topography (m) Policy Run II domain

  5. Current Simulations

  6. CO2 Equivalent Concentration • CRCM CGCM2, 1968 -1994, 2037-2063 IS92a CRCM

  7. CRCM/NCEP CRCM-CRU2 CRU2 Precipitation rate (mm/day)5-year mean: Summer CRU2: Climatic Research Unit TS 2.02 0.5°X 0.5° (Mitchell et al. 2003)

  8. CRCM/NCEP CRCM-CRU2 CRU2 Precipitation rate (mm/day)5-year mean: Winter

  9. CRCM/NCEP CRCM-CRU2 CRU2 Maximum Screen Temperature (ºC) 5-year mean: Summer

  10. CRCM/NCEP CRCM-CRU2 CRU2 Minimum Screen Temperature (ºC) 5-year mean: Summer

  11. CRCM Version 3.6.3 • Improve some biases of 3.6.1 related to the boundary layer: • Retun the control from the planetary waves • Too warm (Tmin) and too wet (pcp) Too much preciptation 1-layer bucket too deep and very wet Excessive cloud cover (Tmin too high) Too much evaporation

  12. Planned Simulations *We have to choose from CGCM2 simulations based on different CO2 emission scenarios. GCMx: A different GCM

  13. CRCM 4.0 • Prototype in development in collaboration with the CRCM Network (R.Laprise et al) • MC2 dynamics + GCMIII physics • Ed Chan MSC, Virginie Lorant CCCma • All CRCM physics and features need to be implemented • Prototype to be completed in early 2005

  14. Variability • Longer timeserie to assess variablity • 25 years simulations instead of 10 years • 2 compoments of the variability: • Intramonthly (seasonal) vs Interannual variability • Intramonthly variability: difficult to validate due to a lack of temporal resolution of gridded observed datasets • Results : Validation of interannual variability

  15. CRCM/NCEP CRCM-CRU2 CRU2 Precipitation Rate (mm/day)5-year Interannual Standard-DeviationWinter

  16. CRCM/NCEP CRCM-CRU2 CRU2 Maximum Screen Temperature 5-year Interannual Standard-Deviation Winter

  17. CRCM/NCEP CRCM-CRU2 CRU2 Minimum Screen Temperature 5-year Interannual Standard-Deviation Winter

  18. CRCM monthly extremes • Precipitations extremes : computed from precipitation archived every timestep (15 min) • Highest precipitation rate for different durations • Wet days for different thresholds • Dry days for different thresholds • Precipitation histogram • Daily extremes of specific humidity (screen) • Daily screen temperature extremes • Highest gusts at the lowest level of the model

  19. CRCM climate extremes(all in early stage of development) • Records of the simulation • Normals of the simulation • Climate indices (Stardex, etc…) • Precipitation histograms • Temperature distributions

  20. 5-year January Daily Precipitation Histogram nearest gridpoint vs station data: Victoria • From the 0.2 mm threashold • 124 / 155 rain days in CRCM • 3 events above 25 mm during the simulation • On average, • MSC obs: 17.8 / 31 (57%) rain days • CRCM : 24.8 / 31 (80%) rain days • Precipitation too frequent Total number of days Average number of days

  21. 5-year January Daily Precipitation Histogramnearest gridpoint vs station data: Kuujuaq • From the 0.2 mm threashold • 100 / 155 rain days in CRCM • 0 event above 25 mm during the simulation • On average, • MSC obs: 15.4 / 31 (49.6%) rain days • CRCM : 20.0 / 31 (64.5%) rain days • Precipitation too frequent [0.2-5[ Total number of days Average number of days

  22. Validation issues • Gridded climatologies • Lack of resolution • Lack of temporal resolution • Lack of variables • Lack of information about the topography (except CRU) • CRCM • Limited time-series • Grid point vs station data • Interpolation of datasets on the CRCM grid

  23. Improving regional climate models • Better representation of surface caracteristics • variables used by land surface scheme • Include smaller lakes • bathymetry, lake surface temperature, ice • from 1968-1999 • Better parameterisations • CRCM ensembles

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