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A CRCM5 Description

A CRCM5 Description. Arctic System Model Workshop III UQÀM, Montréal Bernard Dugas & Katja Winger Environment Canada/RPN July 16, 2009. Where does the CRCM5 come from ? Examples of runs done with CRCM5 / GEM-LAM. GEM, GEM/DM, GEM-LAM GEMCLIM, MC2 CGCM.

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A CRCM5 Description

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  1. A CRCM5 Description Arctic System Model Workshop III UQÀM, Montréal Bernard Dugas & Katja Winger Environment Canada/RPN July 16, 2009

  2. Where does the CRCM5 come from ? • Examples of runs done with • CRCM5 / GEM-LAM • GEM, GEM/DM, GEM-LAM • GEMCLIM, MC2 • CGCM • Dependence on domain size and Using Spectral Nudging • High resolution experiments

  3. Atmospheric models at Environment Canada (EC) Atmospheric Science and Technology Directorate GEM CGCM GEMCLIM Model for climate change studies Model for weather forecasting Monthly and seasonal forecasting CRD/CCCma (Victoria) MRD/RPN (Dorval) CGCM (Canadian General Circulation Model) CRD (Climate Research Division) CCCma (Canadian Centre for Climate Modelling and Analysis) GEM (Global Environmental Multiscale) MRD (Meteorological Research Division) RPN (Recherche en prévision numérique) 4

  4. GEMCLIM GEMCLIM is the climate configuration of Environment Canada's forecast model GEM(Global Environmental Multiscale) global uniform global variable limited area LAM GEMCLIM was originally developed to study systematic errors of the forecast model GEM and is routinely run at RPN as a validation tool. The model is used operationallyfor monthly and seasonal forecasting. As such it is fully supported by Environment Canada

  5. GEM/CRCM5 timelines V1.0.0 (EC, 1998) GEM First (operational forecast) version (Côté, J. et al., MWR 1998a and b) V2.0.0 (EC, 2000) GEM/DMMPI enabled GEM (inspired by MC2) V3.0.1 (EC, 2002) Non-hydrostatic dynamics option (Yeh, K.-S., et al., MWR 2002) V3.1.2 (EC, 2004) GEM-LAMLAM configuration (largely based on MC2) V3.3.0 (EC, 2007) 4DVar Operational 4D Var implementation (Gauthier, P. et al., MWR 2007) V4.0.x (EC, 2009) VStag Vertical staggering (nearly complete) GEMCLIM v3.2.2 => CRCM5.0.0 (UQÀM, 2005; intro to GEMCLIM) GEMCLIM v3.3.0 => CRCM5.0.1 (UQÀM, 2007; extensively used by students and post-docs) GEMCLIM v4.0.x => CRCM5.1.0 (UQÀM, 2010; will include support for CGCM physics) Note that the main difference between GEM and GEMCLIM is in the scripts used by the two models: There are few differences in their dynamics and physicslibraries and +95% of the code is shared.

  6. CRCM5 at UQAM / Ouranos Global and regional, current and future climate scenarios CRCM5 UQAM / Ouranos (Montreal) GEMCLIM MRD/RPN (Dorval) dynamics physics CGCM CRD/CCCma (Victoria) dynamics physics dynamics ? dynamics physics physics physics physics

  7. CRCM5 Numerics Highlights • Time stepping: Fully implicit, two-time level (with 2 Crank-Nicholson iterations) • Arakawa horizontal C-grid (U staggered in x-axis and V staggered in y-axis) • Charney-Phillips vertical staggering (Temp, moisture and W on half levels) • Semi-Lagrangian advection (absolutely stable) • Physic parameterization are treated slab-wise (2D in x-z plane) This implies that the CRCM5 time step need only be determined by the desired precision (of its physics, for example) and not by the numerical stability constraints of its dynamics: Courant numbers above two or three near the upper boundary can be easily accommodated. Note that Courant numbers below 1 should still be the norm in the troposphere. We now can use a 60 minute time step when running global 1,5° simulations and 20 minute at 0.5°.

  8. Arctic SLP, Smaller Domain, 1983-2002 (next slides from M. Qian) CRCM5 Diff ERA40 Summer Winter

  9. A suite of CRCM5/GEM integrations are being compared to evaluate the overall performance of the model in representing Arctic climate processes. Before coupling LAM model to an Arctic Regional Ocean Model. In the next set of results 4 model runs are compared to ERA40. • CRCM5-LAM (0.5°) forced by ERA40 2. CRCM5-LAM (0.5°) forced by LBCs from a GEM-Global integration at 2° 3. CRCM5-Variable resolution grid. With the high resolution telescoped region of the global grid being at 0.5° resolution and covering almost the exact same area as the CRCM5-LAM runs in 1 and 2 above. The outer regular region of the global-variable grid is at 2° resolution • CRCM5-GLOBAL, uniform resolution at 2° All runs used AMIP SSTs for the period 1979-2004, CRCM5 version 5.0.1

  10. Winter SLP, Larger Domain, 1979-2001 Piloted by ERA40 Piloted by GEM Global 2.0 DEG CRCM5 Variable GEM Global 2.0 DEG ERA40

  11. What happens when Spectral Nudging is used ? No nudging Nudging UV Winter SLP (DJF 1978) differences between CRCM5 and ERA40

  12. Example of high-res work at EC with GEM-LAM (project UNSTABLE config, courtesy of J. Milbrandt) • Daily12-hour forecasts • 1-km driven by 2,5-km • Non-hydrostatic models • 1-km: 412x482x58, 30s • 2,5-km: 648x470x58, 60s • Uses proposed Vancouver • Olympic setup Investigation of convective initiation and forecasting of deep convective storms in south-central Alberta from July to the end of September ‘09

  13. Merci / Thank you

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