Irina Sandu , Jean-Louis Brenguier, Olivier Geoffroy
description
Transcript of Irina Sandu , Jean-Louis Brenguier, Olivier Geoffroy
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Irina Sandu , Jean-Louis Brenguier, Olivier Geoffroy
CNRM/GMEI/ MNPCA
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CNRM/GMEI/ MNPCA
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
I. Introduction
II. Application of the LES technique for studying the indirect effect of aerosols
Méso-NH as a LES code
Validation on FIRE-I case
III. Large-Eddy simulations of different cases of marine stratocumulus
IV. Conclusions
3Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
CNRM/GMEI/ MNPCA
I. Introduction
II. Application of the LES technique for studying the indirect effect of aerosols
Méso-NH as a LES code
Validation on FIRE-I case
III. Large-Eddy simulations of different cases of marine stratocumulus
IV. Conclusions
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Considerable coverage + optical properties
10~.
océan
Sc
A
A
Complexe interaction between dynamics - microphysics - radiation
Negative radiative forcing r
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
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Twomey (1977): LWP constant NCCN Nc albedo
Albrecht (1989): NCCN Nc re
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
Suppression of drizzle
formation
The cloud life time
LWP constant
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CNRM/GMEI/ MNPCA
I. Introduction
II. Application of the LES technique for studying the indirect effect of aerosols
Méso-NH as a LES code
Validation on FIRE-I case
III. Large-Eddy simulations of different cases of marine stratocumulus
IV. Conclusions
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
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Complexe interaction dynamics – microphysics - radiation
set of parametrisations adequate and coherent
New parametrisation for the single scattering albedo based on aerosol chemical composition for LES modelling of boundary layer clouds
Sandu I., P. Tulet and J.L. Brenguier, Geophys. Res. Lett., 32, L19814, 2005
Turbulence scheme – 3D scheme (Cuxart-2000) – TKE equation +1.5 closure + Deardorff mixing lengthAdvection scheme – positively defined second order centered scheme
Microphysics – Khairoutdinov &Kogan 2000 (O. Geoffroy )
– 2 moments bulk scheme developed for Sc.
Radiative code (ECMWF) – coding problems: the cloud overlap (O. Thouron)
LW – Savijarvi (1997) • cloud optical
properties SW - Fouquart (1987) not suited for LES of marine stratocumulus
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
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The initialisation followed the intercomparison exercice (Duynkerke et al. 2004)
•2.5kmX2.5kmX1.2km – 50mX50mX10m
• initial profiles
•Subsidence w=-1x10-5 x z m/s
•Forcings on L et qT (large scale advection)
•No precipitations
L et qT
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
0.7g/kg
0LT 12LT 0LT 12LT
700mrc(g/kg)
0LT 12LT 0LT 12LT
LWP (
g/m
2)
250g/m2
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CNRM/GMEI/ MNPCA
I. Introduction
II. Application of the LES technique for studying the indirect effect of aerosols
Méso-NH as a LES code
Validation on FIRE-I case
III. Large-Eddy simulations of different cases of marine stratocumulus
IV. Conclusions
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
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Simulations initialized with various CCN concentrations, for several large scale forcings
CCN impact drizzle, the diurnal cycle amplitude, the LWP, the surface and radiative fluxes, the boundary layer energetics
the impact of CCN on the stratocumulus capped boundary layer evolution
how the system response depends on the external conditions (large scale horizontal advection, subsidence, etc…)
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
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LW
P (
g/m
2)
0 LT 12 LT 0 LT 12 LT
W6 : subsidence w = - 6X10-6 z (m/s) Nccn= 50, 200, 600 cm-3
no large scale advection
Nc LWP
Nc LWP
Nc ~ 40, 120, 220 cm-3
W4 : subsidence w = - 4X10-6 z (m/s) Nccn= 50, 600 cm-3
no large scale advection Nc ~ 40, 220 cm-3
subsidence w = - 6X10-6 z (m/s) Nccn= 50, 600 cm-3
1K/day cooling1K
Nc ~ 40, 220 cm-3
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CNRM/GMEI/ MNPCA
I. Introduction
II. Application of the LES technique for studying the indirect effect of aerosols
Méso-NH as a LES code
Validation on FIRE-I case
III. Large-Eddy simulations of different cases of marine stratocumulus
IV. Conclusions
Meeting on the Parametrisation of Boundary Layer Clouds , Toulouse, 3rd – 4th July 2006
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