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Cloud-radiation interaction as simulated by the Canadian GEM model compared to ARM observations

Cloud-radiation interaction as simulated by the Canadian GEM model compared to ARM observations. Danahé Paquin-Ricard Director : Colin Jones Codirector: Paul Vaillancourt. Source:http://www.cs.pitt.edu/. 1. Motivation. Cloud-Radiation Interaction. Microphysics. Macro. Environment.

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Cloud-radiation interaction as simulated by the Canadian GEM model compared to ARM observations

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  1. Cloud-radiation interaction as simulated by the Canadian GEM model compared to ARM observations Danahé Paquin-Ricard Director: Colin Jones Codirector: Paul Vaillancourt Source:http://www.cs.pitt.edu/

  2. 1. Motivation Cloud-Radiation Interaction Microphysics Macro Environment Precipitation Surface Radiative Budget

  3. Microphysics: Sundqvist Deep convection: Kain-Fritsch Shallow convection: Kuo-Transient Advection Prognostic variables : T, qv, qc, qs, qr Parameterization: Cloud fraction f(RH) & vertical overlap Liquid-ice separation & effective radii f(T) Diagnostic variables: Cloud fraction LWC, IWC rei, rel Radiation: Correlated-K 2. GEM-LAM v.3.2.2

  4. 3. Simulations Simulations: • 53 vertical levels • Horizontal resolution: 0,5° • Time step: 30 min • Prescribed SSTs & ice fraction • LBCs: ERA40 & ECMWF • 7/8 years: 1998-2004/05 Source: Ayrton Zadra & Paul Vaillancourt

  5. NSA SGP Source: http://www.arm.gov 4. Observations ARM (Atmospheric Radiation Measurement Program) • SGP (Southern Great Plains) • NSA (North Slope of Alaska) Observations: • SWD and LWD • LWP and IWV • Cloud fraction • Precipitation • Surface T & p

  6. 5. Results • 3 hourly-mean (except for precip.: 3 hourly accumulation) • Radiation fluxes: function of cloud fraction • Clear-sky: CF<10% • Overcast: CF>90% • All-sky • LWP & IWV: only when precipitation ≤ 0,25mm/3h

  7. 5. Cloud fraction, IWV & LWP

  8. 5. Cloud fraction, IWV & LWP

  9. 5. Cloud fraction, IWV & LWP

  10. 5. SWD vs. IWV: clear sky (≤10 %)

  11. Local Time (h) 5. SWD vs. IWV: clear sky (≤10 %) C

  12. 5. LWD vs. IWV: clear sky (≤10 %)

  13. 5. LWD vs. IWV: clear sky (≤10 %)

  14. 5. SWD vs. LWP: overcast(≥90%)

  15. Local Time (h) 5. SWD vs. LWP: overcast(≥90%)

  16. 5. LWD vs. LWP: overcast(≥90%)

  17. 5. LWD vs. LWP: overcast(≥90%)

  18. 5. SWD + CF underestimated

  19. 5. LWD + CF underestimated

  20. 6. Conclusion • Cloud-radiation interaction can modify surface radiative fluxes by different ways • Verification of individual components is important

  21. Thank you for your attention… Questions ?

  22. 6. A feedback example Underestimate Cloud fraction Underestimate IWV Less evaporation Overestimate SWD Drier Surface Overestimate near surf. Temperature

  23. 5. Résultats D

  24. 5. LWP

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