Hélène Côté and Daniel Caya
Climate Simulations Group
Consortium Ouranos
Variability and Extremes in the CRCM
Development of Scenarios of Climate Variability and Extremes: Current Status and Next StepsVictoria, 16-17 October 2003
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
From Policy Run II to Policy Run III 3.5.1 vs 3.6.1
Radiation Fouquart and Morcrette unchanged
Land surface Beautified Bucket ( 1 layer + force-restore)
unchanged
Convection Kain-Fritsch (1990) Bechtold-Kain-Fritsch (Bechtold et al 2001)
Clouds F (relative humidity) F (relative humidity) + convective clouds
Boundary layer Bulk transfert, mixing lengh-K unchanged
Atmospheric composition
Specified [O3] [CO2] unchanged
Nesting Davies relaxation Spectral nudging
( Biner et al 2000 , Denis et al)
SSTs From Monthly GCM values From Daily GCM values or AMIP obs.
Lake Model No Mixed-layer (Goyette et al 2000)
Leap-year No Yes
New features Implicit treatment of Tg
Atmospheric budget
Current Simulations Configuration
• 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….
Topography(m)
Policy Run IIdomain
Current SimulationsDriving data
Ocean Period Spectral nudging
CRCM Done(14/10/03)
NRA-1 AMIP 1973-1999
yes 3.6.1 133 / 364
NRA-1 AMIP 1973-1999
no 3.6.1 95 / 364
CGCM2 is92a
CGCM2 1968-1994
yes 3.6.1 92 / 364
CGCM2 is92a
CGCM2 2037-2063
yes 3.6.1 90 / 364
Precipitation rate (mm/day)5-year mean: Summer
CRCM/NCEP
CRU2
CRCM-CRU2
CRU2: Climatic Research Unit TS 2.020.5°X 0.5° (Mitchell et al. 2003)
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)
1-layer bucket too deep and very wet
Excessive cloud cover(Tmin too high)Too much evaporation
Too much preciptation
Planned SimulationsDriving data
Ocean Period Spectral nudging
CRCM Start
CGCM2 scenario *
CGCM2 scenario *
1xCO2
2xCO2
yes 3.6.3 Early 2004
CGCM2 scenario *
CGCM2 scenario *
1xCO2
2xCO2
yes 3.6.3 Early 2004
GCMx GCMx 1xCO2 2xCO2
yes 3.6.3 Early 2004
*We have to choose from CGCM2 simulations based on different CO2 emission scenarios.
GCMx: A different GCM
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
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
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
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
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
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5-year January Daily Precipitation Histogram nearest 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[
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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