Transcript Parametrisation in ALADIN - RC-LACE

Parameterization
and physico-dynamical interface
Garde
developments for the LAM ALADIN and CSRM AROME
Jean-Marcel Piriou, Météo-France.
EWGLAM / SRNWP Workshop, Zürich 9-13 October 2006.
Introduction
Operational and research models operated: designing unified schemes
Global ARPEGE
Aquaplanet mode
SCM ARPEGE
(EUROCS, GATE,
TOGA,BOMEX,
ARM, RICO, …)
Global regular ARPEGE
PHYSICS
LAM ALADIN / 3DVAR / 5-10 km
CSRM AROME / 3DVAR / 2.5 km
Global stretched ARPEGE / 4DVAR-ass. / 23 to 133 km
Introduction
Several operational and research models operated
Sharing parameterizations between models:
1. Simpler to manage a single set of source
codes.
2. Feedback from cases studies, scores,
users  modifications  improve also
the other models.
3. Sharing a simple and general concept 
better understanding: convection, …
Summary
On-going efforts in designing unified equation sets:
1. Subgrid-scale convection: 3MT Fit wider range of
grid sizes (GCM - LAM - CSRM).
2. Grid-scale: Catry et al. 2006 equations: fluxconservative thermodynamic equations.
3. Phys.-dyn. diagnostics: shared between GCM – LAM CSRM
CSRM AROME developments
1. Testing the prototype
2. Subgrid-scale shallow convection
Fin
3MT: A convective scheme using
separate microphysics and transport
terms in grid-scale equations
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Separating microphysics and transport in grid-scale convective equations
(Q1c: réchauffement convectif, Q2c: assèchement convectif fois L)
Buoyant convective condensation
Unbuoyant convective condens. (overs.)
Cloudy evaporation
Transport
Net condensation
Precipitation evaporation
SH précip., melt.
Transport
3MT:
3MT
M & T coupled:
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
3MT:
Consequences:
•
Grid-scale equations of the SGS convective scheme are
closer to those of CSRM or LES.
•
Can share microphysical modules between CSRM and
parameterization.
•
Validation of the parameterization versus CSRM or LES
can be done for each of the above terms.
•
No need to assume a stationnarized cloud budget  more
consistent with a future prognostic equation of cloud
fraction.
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
What has been done so far
3MT:
First prototype with
•
Deliberately crude microphysics (simple condensation
scheme, autoconversion/collection, diagnostic q_r q_s,
Kessler-type evaporation)
•
New proposal for entrainment
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Mass flux / vertical velocity in the SGS convectif updraft
3MT:
Taking into account the overshoots.
Vertical integral of buoyancy
Top
LNB
P & NH effects Siebesma et al. (2003)
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Cold pools and entrainment
Shallow cumulus phase
High entrainment:
  10 m
3
1
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Cold pools and entrainment
Precipitating cumulus phase
Intermediate entrainment:
  6 10 m
4
1
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Cold pools and entrainment
Deep convection phase
Low entrainment:
  310 m
4
1
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Entrainment: an heuristic proposal: prognostic link evap. prec.  entr.
3 104 m1
103 m1
Entrainment epsilon depends on local pressure and
on zeta, probability of undiluted ascents at the
current level
Zeta’s source is precipitation evaporation, zeta’s sink
is a linear relaxation to zero.
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Results on the EUROCS diurnal cycle of deep conv. over land
Q2
ARPEGE
oper
Piriou, Redelsperger, Geleyn, Lafore,
Guichard, Subm. JAS 2006.
ARPEGE
V1
Q2 CSRM
MNH
Q2
ARPEGE
historical
entr.
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Partly resolved convection: Luc Gerard
3MT:
To run in the « grey zone »
•
A large scale condensation scheme based on Smith
(1990).
•
A prognostic mass-flux scheme extended from Gerard
and Geleyn (2005).
•
3MT equations, Piriou (2005).
•
Microphysical routine derived from Lopez (2002).
•
Prognostic mass-flux parameterization of a moist
downdraft driven by evaporative cooling.
3MT (Modular Multiscale Microphysics and Transport Convective Scheme)
Partly resolved convection: Luc Gerard
Fin
Flux-conservative
thermodynamic equations
Flux-conservative thermodynamic equations
An equation framework, ready for discretization
•
Total-mass based framework, use of the full
barycentric velocity as the vector of advection.
 Even in full prognostic treatment of cloud and
prec. Processes, flux conservative form of all
relevant budgets.
 Flux conservative form kept when going from HPrim. equ. To fully compressible system.
Catry, Geleyn, Tudor, Bénard, Trojakova, Tellus
(2006)
Flux-conservative thermodynamic equations
Catry, Geleyn, Tudor, Bénard, Trojakova, Tellus (2006)
Dark grey:
unrecommended
choices
Increasing realism
Fin
AROME developments
1/ Testing the prototype
Prototype AROME
Source Yann Seity, Météo-France/CNRM GMAP 2006.
Domaines AROME configurés sur la FRANCE
Source Yann Seity, Météo-France/CNRM GMAP 2006.
PARI
BRET
NORE
MIDPYR
FRAN
SUDE
MIDPYR depuis Juin 2005 + SUDE sept-dec 2005,
NORE dec2005-avr2006, PARI mai-sept2006
22
Orages (22-05-2006)
Source Yann Seity, MétéoFrance/CNRM GMAP 2006.
13TU
Fin
AROME developments
2/ Subgrid-scale shallow
convection
AROME developments
Subgrid-scale shallow convection: S. Malardel, V. Masson, J. Pergaud
Subgrid mixing:
Eddy diffusivity
w   K

z
 



w
t
z
Mass-flux
w   M (u   )
M   wu 
AROME developments
Subgrid-scale shallow convection: S. Malardel, V. Masson, J. Pergaud
χc
0
EDKF updraft
prototype
  Mt χf(χ)dχ

1

χc
  Mt ( 1 χ)f(χ)dχ
Mu    
u   u
LCL
CE (1  )Mu
Ldn
C  (1   )M u

Lup

D
From Lappen and Randall,
2001

 
From Kain and Fritsch,
1990
θl u  θl  
w'θ'
rt u  rt  
(surface fluxes)
SURFEX
surf
e
w'r'
surf
e
 
1/ 3
 g

Mu  C   
w'θ' surf  Lup
 vref

AROME developments
Subgrid-scale shallow convection: S. Malardel, V. Masson, J. Pergaud
Rico : high resolution composite case
No shallow convection scheme
Explicit cloud
under a strong inversion
AROME developments
Subgrid-scale shallow convection: S. Malardel, V. Masson, J. Pergaud
Rico : high resolution composite case
EDKF (Pergaud, Malardel, Masson)
with subgrid autoconversion
Rain specific content (g/kg)
Fin
Conclusions
Conclusions / perspectives
•
On-going efforts to develop unified
approaches: 3MT, grid-scale equations
sets, microphysics, DDH physicodynamical diagnostics.
•
AROME prototype: developments and
validation under progress.