Status of ARPEGE / ALADIN physics F.Bouyssel M é t é o-France Mesoscale physics and diagnostics tools 12-13/12/2005

Presentation 1. Operational physics 2. Known problems 3. Current developments

Operational physics

ARPEGE (global) and ALADIN (LAM) models ARPEGE : Global spectral model with stretched resolution 23 to 130 km, 41 levels (1 hPa), 982s, 4 runs/day, 4D-Var (T107, T149) : 6h assimilation cycle ALADIN : LAM, coupled with ARPEGE ~ 10 km, ~ 41 levels (1 hPa), ~ 450s Dynamical adaptation or 3D-Var Others operational configurations : ARPEGE Tropics and ALADIN models  Numerical weather prediction  Climat simulations ARPEGE-Climat : ~ 250 km ALADIN-Climat : ~ 50 and 20 km Same dynamics: H, 2SLSI

Physics in ARPEGE/ALADIN PNT-CLIMAT SURFACE ISBA (Noilhan and Planton 89, Mahfouf and Noilhan 96, Giard and Bazile, 2000) 2/4 layers force restore scheme (T,W,Wg), bare ground and vegetation fraction, 1 layer snow scheme with pronostic albedo RADIATION (2 schemes) 1) ACRANEB (Geleyn and Hollingsworth 79, Ritter and Geleyn 92) : every time step 2) FMR15 (Fouquart and Bonnel 80, Morcrette 93) : every 1h or 3h Tegen aerosols, UGAMP ozone climatology Randow maximum overlap assumption MOUNTAIN DRAG linear and « form » drag, anisotropy, resonance, « lift » effect important modifications (Geleyn et al., Catry et al. submitted)

Physics in ARPEGE/ALADIN PNT-CLIMAT TURBULENT VERTICAL DIFFUSION : 2 schemes 1) 1st order K diffusion scheme (Louis et al. 81) + modifs in stable case + interactive mixing lengths, shallow convection (Geleyn 87), anti-fibrillation (Bénard et al. 00) 2) TKE diagnostic (Mellor/ Yamada 2.0) + « moist » (« F0/F1/F2 » de Bougeault) LARGE SCALE PRECIPITATION AND CLOUDS : 2 diagnostic schemes 1) revised Kessler type (evaporation, melting, freezing), cloud condensates diagnosed with RHc and buoyancy, cloudiness with Xu&Randall (96) formulation 2) Ricard-Royer statistical scheme SUBGRID PRECIPITATION AND CLOUDS Mass flux scheme with a Kuo-type closure (Bougeault 85), vertical transport of horizontal momentum, vertically varying detrainment and entrainments rates, downdrafts (Ducrocq and Bougeault 95), etc.

Known problems

*Diagnostic schemes for precipitation and clouds (no microphyics) : lack of more physical relations between clouds and precipitations *Overestimation of small rainfall events ( < 3 mm/day) particularly in the Tropics but also in mid-latitudes (more sophisticated microphysics, triggering of convection,...)

Known problems *Overestimation of precipitation over mountains (envelop orography, diagnostic RR schemes, moisture convergence) ALADIN ARPEGE RR error using raingauges (JAS 2005)

*Underestimation of low level clouds (turbulence with cloud top entrainment, microphysics, shallow convection) Known problems TOP SW : MODEL – CERES (DJF)

*Diurnal cycle of convection *Problem of transition between shallow and deep convection *Lack of moist convection in case of no synoptic forcing (moisture convergence only) *Top of convection at neutral level (Guichard et al., 2004) (Guichard et al., 2004) Known problems

MESO-NHARPEGE Q2 25%, 50%, 70% or 90% relative humidity *Lack of sensitivity to humidity environment Known problems (Piriou, 2005) (Piriou, 2005)

Current developments

All problems presented before are common to all ARPEGE/ALADIN - PNT or Climat models Convergence of NWP and Climat ARPEGE/ALADIN physics towards more sophisticated physical parametrisarions for resolutions above 10km with a maximum of synergy with finer scale physics when possible!

MICROPHYSICS qv ql qi qr qs condensation evaporation autoconversion collection autoconversion collection fall evaporation sublimation melting Original scheme : Lopez, 2001

MICROPHYSICS Cloud statistical scheme with triangular PDF: Smith, 90 Dependency of  with  x and  Separation of qc in ql, qi function of temperature Kessler type autoconversion (threshold and rate funtion of T) Specification of hydrometeor distributions for coll., evap., subl. : Concentration : N(D) = N 0 exp(- D) (Marshall-Palmer) Mass: M(D)=  D  Fall velocity: V(D)=  D  Precipitation sedimentation : semi-lagrangien conservative schema Constant fall speed for snow and rain (0.9 and 5 m/s)

Case study : 09/12/2004

Austrian alpin case (9 december 2000) Oper Observations (from ZAMG) New (Haiden and (Haiden and Wittman) Wittman)

operLopez Lopez no advection of qrLopez no advection of ql, qi and qr Impact of advection

Operational at ECMWF and used in MESO-NH and AROME Rayonnement thermique : RRTM (Mlawer et al., 97)(Morcrette et al.,98) Rayonnement solaire : (Fouquart and Bonnel, 80)(Morcrette,93) Maximum randow overlap assumption Cloud optical properties : liquid water cloud : SW / Fouquart (87), LW / Smith-Shi (92) ice water cloud : SW / Ebert-Curry (92), LW / Smith-Shi (92) Coud effective radius : liquid water cloud : Martin et al. (94) ice water cloud : Sun et al. (01) RADIATION

TEST-SUITE (july-nov 05) - Pronostic microphysics + RRTM/SW6 radiation + vertical diffusion of cloud conservative variables (qt, sl) - Remove biais of RS + more EARS data and SATOB data - New climatological files Improvment in ARPEGE and ALADIN forecasts on cloud, precipitation and wind fields BUT Degradation of geopotentiel scores after 60h forecast over Europe in assimilation mode but not in forecast one! Problem of microphysics tunings linked with stretched grid? Degradation of linear tangent approximation? Problem with obs modifications linked with bias?

DJF - AMIP (forced) Mean Sea Level Pressure (hPa) MOUNTAIN DRAG (Déqué) OPER NEW

SURFEX (externalized surface) Vegetation and soil : ISBA (Interface Soil Biosphere Atmosphere) Town : TEB (Town Energy Balance) Lakes : prescribed temperature, Charnock formula Sea and ocean : prescribed SST, Charnock formula  will soon include a better bulk formulation  reflexion to implement a 1D oceanic mixing layer

ISBA physics Soil options: Force restore, 2 layers, temp, water, ice Force restore, 3 layers, temp, water, ice Diffusion, N layers, temp, water, ice Vegetation options: Noilhan and Planton 89 (~Jarvis) AGS (photsynthesis and CO2 exchanges) AGS and iteractive vegetation Hydrology options: no subgrid process subgrid runoff, subgrid drainage Snow options: Douville 95 (1 layer, varying albedo, varying density ) Boone and Etchevers 2000 (3 layers, albedo, density, liquid water in snow pack) Tiling : 1 to 12 patches

TURBULENT VERTICAL DIFFUSION Moist variables Redelsperger and Sommeria( 81), Bougeault (82) and Bechtold (93) TKE-l Cuxart et al (2000)

Diffusion : In Hirlam : Mixing length : with Bougeault and Lacarrère (89) with now

CONVECTION Modifications around current scheme using CAPE for CVNP and CVP (Gueremy) Modifications around current scheme using CAPE for CVNP and CVP (Gueremy) Proposition of equations « MT-CCF » for developing convective parametrizations Proposition of equations « MT-CCF » for developing convective parametrizations  Move the parametrization effort from detrainment towards microphysics.  Continuity : CV dry  CVNP  CVP  Easier validation with CRM  (Gerard, Piriou, Geleyn, Stiperski) 2 works :

CRMMNH ARPEGEnew ARPEGEoper (Piriou, 05)

CRMMNH ARPEGEnew ARPEGEoper

Low clouds ( hPa) mean JJA : EXP - ISCCP ARPEGE climat reference ARPEGE climat TKE pron. (CBR) with top PBL entraînement Microphys pron. CVPP+CVP (CAPE) (Marquet & Gueremy)

CONCLUSION Common physics for >10km (PNT and Climat) Common physics for >10km (PNT and Climat) Lot of common points with finer scale physics (surface, radiation, turbulence, convection ?). Potentially important for coupling. Lot of common points with finer scale physics (surface, radiation, turbulence, convection ?). Potentially important for coupling. Need common phys/dyn interface and diagnostics for large collaboration (cross validation, etc...) Need common phys/dyn interface and diagnostics for large collaboration (cross validation, etc...)