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Update on model development Meteo-France. CLOUDNET workshop - Exeter 5-6/04/2004. François Bouyssel. Summary. Model outputs for CLOUDNET database Modifications in the cloudiness and radiation schemes should become operational soon (beginning of May) Perspectives.
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Update on model development Meteo-France CLOUDNET workshop - Exeter 5-6/04/2004 François Bouyssel
Summary • Model outputs for CLOUDNET database • Modifications in the cloudiness and radiation schemes should become operational soon (beginning of May) • Perspectives
Model variables for CLOUDNET database 1) Model • Global model : ARPEGE (stretched mesh ~ 25 km over west Europe) • 36h forecasts based on 00h UTC produce hourly outputs for CLOUDNET • sites (nearest grid point) fluxes, variables 2) New fields will be provided soon (May 2004) • T2m, q2m, U10m, V10m • Altitude • Dynamical and thermal roughness lengths • Albedo • Boundary layer height • Downward solar and thermal fluxes 3) Currently delivered once a month real time (?)
Changes in the cloudiness and radiation schemes
Introduction • Diagnostic schemes : • - Precipitation (stratiform, convective) • - Cloud condensates (liquid and solid) • - Cloudiness • Cloud condensates and cloudiness inputs of radiation scheme q_liquid q_ice Radiation (SW, LW) Neb Change in ARPEGEsince 14th April 2003
Malcolm Brooks, University of Reading. – R.M.S. – Norwich, 2003 Pre April~14 April~14 onwards
Modifications in the new cloudiness scheme Weaknesses of the current situation (Oper) : • Too much 0/1 cloudiness fraction • Not enough q_ice content Modifications (Mod) : • Modification in Xu & Randall cloudiness formulation • Convertion coefficient of potential water vapor excess to cloud condensate (as) dependent on q_sat • New tunings
Cloud condensates Cloudiness Comparison of cloud condensates and cloudiness(Oper versus Mod)
q_liquid q_ice Neb Oper : Mod :
SSMI climatology July 87-88-89 SSMI Q_ice Q_liquid Oper : Mod : Q_total
Oper : Mod :
Radiation schemes 1) Operationnel one (SW & LW) (Geleyn and Hollingsworth 1979) • Very robust and efficient code (cost ratio with FMR around 20 !!) • Called every time step : full consistency for cloud/radiation interactions • Improved in February 2003 : LW exchanges between atmosphere and surface 2) Fouquart (SW), Morcrette(LW), Radiation : FMR (Morcrette 1989) • Full radiation part called every 3 hours (SW transmissivities, LW fluxes) • LW spectrum divided into 6 spectral regions • SW spectrum divided into 2 spectral regions
Comparison of LW radiation schemes with low level cloud(zoom near the surface)
Zonal tendency of Qv Global tendency of Qv Oper Mod Mod+FMR15 Impact of FMR15
Perspectives • New physical package in development for ARPEGE • Pronostic TKE scheme • Pronostic microphysics • New convection scheme (deep and shallow) • 2km AROME prototyp in development • Wish to enlarge the use of CLOUDNET data : • Validation of research development • Which data could be used and associated error bars? • Cloud fraction, LWP, IWP, Cloud base, PBL height, ... • Is it possible to use programs to produce « quicklooks » graphics?