Download presentation
Presentation is loading. Please wait.
Published byArchibald Anthony Modified over 9 years ago
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 MacroMicrophysicsEnvironment Cloud-Radiation Interaction Surface Radiative Budget Precipitation
3
2. GEM-LAM v.3.2.2 Diagnostic variables: Cloud fraction LWC, IWC r ei, r el Parameterization: Cloud fraction f(RH) & vertical overlap Liquid-ice separation & effective radii f(T) Radiation: Correlated-K Prognostic variables : T, q v, q c, q s, q r Shallow convection: Kuo-Transient Deep convection: Kain-Fritsch Advection Microphysics: Sundqvist
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
Source: http://www.arm.gov NSA SGP 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
10
5. SWD vs. IWV: clear sky (≤10 %)
11
C Local Time (h)
12
5. LWD vs. IWV: clear sky (≤10 %)
14
5. SWD vs. LWP: overcast (≥90%)
15
Local Time (h)
16
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 Drier Surface Less evaporation Overestimate near surf. Temperature Underestimate Cloud fraction Overestimate SWD Underestimate IWV
23
5. Résultats D
24
5. LWP
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.