Jean-Marcel Piriou
Centre National de Recherches Météorologiques
Groupe de Modélisation pour l’Assimilation et la Prévision
Update on model developments: Meteo-France
NWP model / clouds and turbulence
CLOUDNET Workshop / Utrecht 21-22/10/2002
Global ARPEGE
Aquaplanet mode
SCM ARPEGE
(EUROCS, GATE,
TOGA,BOMEX,
ARM, …)
Global regular ARPEGE / 4DVAR-ass. / 66 km
PHYSICS
LAM ALADIN / coupled / 10 km
Global stretched ARPEGE / 4DVAR-ass. / 20 to 200 km
Present operational Under progress
schemes
Geleyn and Hollingsworth More accurate infra-red
Radiation (1979), Ritter and Geleyn exchanges between
(1992) surface and layers
Diagnostic in ql/i, all Prognostic ql/i, qr/s
Grid-scale cloud supersaturation removed,
scheme liquid/ice condensation T,
melting/ freezing/ evaporation/
Kessler (1979), Clough and
Franks (1991)
mass-flux scheme, CISK-type Modified trigger functions
Subgrid-scale closure and triggering, water (TKE, CIN)
cloud scheme vapour budget using a Kuo-
type closure, downdrafts,
(convection) momentum flux
1st order closure scheme after PrognosticTKE scheme,
Turbulence Louis (1979), Louis and al. mixing « Betts »
(1981), using a flux-gradient K- conservative variables
theory with Ri dependency, thetal and qt instead of
variable roughness lengths theta and qv
over sea (Charnock)
Perspectives operational model (GCM 20-200km
ARPEGE + LAM 10km ALADIN)
• March towards new prognostic cloud and turbulence
variables: ql/i, qr/s, TKE, w_ud, w_dd
• EUROCS: 3 transition cases (well posed lateral conditions
to compare CRMs to GCMs or LAMs)
• Model to satellite, data assimilation cycle
• CLOUDNET: (long time series, detailed profiles) colocated
ql/i, qr/s, PBL depth, cloudiness, close TEMP data to
provide in-situ validation of new microphysics / turbulence
Perspectives 2: a CRM in operations around 2008!...
• 2003: first tests of the existing CRM méso-NH physics in
the ALADIN-NH 2.5km dynamical core need for
validations within CLOUDNET?