meso-nh model

Meso-NH model

30 users laboratories

http://www.aero.obs-mip.fr/mesonh

A research model, jointly developped by Meteo-France and Laboratoire d’Aérologie (CNRS/UPS)

http://www.aero.obs-mip.fr/mesonh

http://www.meteo.fr/

Examples of Applications of Examples of Applications of Meso-NHMeso-NH

• General description of Meso-NHGeneral description of Meso-NH• Grid nesting Grid nesting • Clouds representation (explicit convective clouds, Clouds representation (explicit convective clouds,

Sc)Sc)• Cyclones Cyclones • Coupling with the surface Coupling with the surface • Coupling with other models (hydrology, Coupling with other models (hydrology,

dispersion)dispersion)• DiagnosticsDiagnostics• Systematic validations (climatology, real time Systematic validations (climatology, real time

runs)runs)• Towards AROMETowards AROME

General description of Meso-NH

Anelastic equations with the pseudo-incompressible system of Durran

• Vertical coordinate following the terrain : (Gal Chen and Sommerville, 1975)

• Temporal discretization : Purely explicit leap-frog scheme

• Advection scheme : 2nd order eulerian schemes

•Spatial discretization : Arakawa C grid

• Grid nesting : One-way/Two-way

• Initial fields and LBC (radiative open) from ECMWF/ARPEGE/ALADIN.

S

S

zH

zzHz

•Turbulence : 1.5 order closure Cuxart-Bougeault-Redelsperger (2000)

• Convection : Kain-Fritsch (1993) revised by Bechtold et al. (2001)

• Microphysical scheme : Bulk schemes at 1-moment or 2-moments. Up to 7 prognostic species: vapor (rv), cloud (rc), rain (rr), pristine ice (ri), snow (rs), graupel (rg), hail (rh)

• Radiation : ECMWF package

• Chemical on-line scheme : Gazeous and aerosols (Presentation C.Mari, Thursday)

• Externalized surface model (Presentation P.Le Moigne, this afternoon)

DYN

AM

ICS

PH

YSIC

S

Types of simulationsTypes of simulations

A broad range of resolution from synoptic scales A broad range of resolution from synoptic scales ((x~10km) to meso-scale (x~10km) to meso-scale (x~1km) to Large x~1km) to Large Eddy Simulation (Eddy Simulation (x~10m) x~10m)

• Real cases (from ECMWF, ARPEGE, ALADIN Real cases (from ECMWF, ARPEGE, ALADIN analyses or forecasts)analyses or forecasts)

• Ideal cases Ideal cases unrealistic cases unrealistic cases- Academic cases (validation of the - Academic cases (validation of the

dynamics)dynamics)- Basic studies (Diurnal cycle …) : Cloud - Basic studies (Diurnal cycle …) : Cloud

Resolving Model (CRM)Resolving Model (CRM)- To reproduce an observed reality (via - To reproduce an observed reality (via

forcings)forcings)(intercomparison : GCSS, EUROCS …)(intercomparison : GCSS, EUROCS …)

Simulations 3D, 2D, 1DSimulations 3D, 2D, 1D

Grid nesting technics

At every time step :

The Coarse Model (CM) gives the lateral boundary conditions to Fine Model (FM) by interpolation

One-way : the FM doesn’t influence the CM

Two-way : CM fields are relaxed to the average of FM fields

A single constraint : an integer ratio between the resolutions and the time stepsSame vertical grids.

Vaison-la-Romaine : 22 september 1992

3 nested grids : 40/10/2.5km

Instantaneous precipitations 2.5km

One-way Two-way

Stein et al., 2000

Cumulated precipitations for 9h(Obs=300mm en 6h)

One-way Two-way

Stein et al., 2000

2.5 km

10km

Vaison-la-Romaine : 22 september 1992

Mixed phase cloud representation with a bulk

scheme

0°C 0°C

Mixed phase :

Liquid phase :

Ice crystals

Snowflakes

Graupel

Hail

Cloud droplets

Cloud properties = f( , , , , , )

Cloud droplets

Raindrops

0°C

Autoconversion

0°C

The different processes

RimingAggregation

Collection Collection

Deposition

Freezing

Nucleation

Melting

Sedimentation

MESO-NH Explicit microphysical scheme :

Instantaneous precipitation

2.5km2-way without ICE

2-way with ICE

Stein et al., 2000

Lafore Moncrieff 89

Stratiform

Density Current

Convective

HD

A tropical squall line (P.Jabouille) : Idealized

simulation according to a real case (COPT81)

U

W

Cloud droplets Rain drops

Pristine iceGraupel

Snow

Jabouille. Caniaux et al., 1994

Three contrasted MAP cases

IOP 2A

Strong Convection

IOP 3

Moderate Convection

IOP 8

Stratiform rain

F.Lascaux and E.Richard, 2005

18:00 UT

19:00 UT

20:00 UT

Microphysical retrievals : IOP 2A (intense convection)

12

km

100 kmTabary, 2002

(x) hail + graupel

(o) hail ( ) rain

Z > 60 dBz

Radar Retrieval (S-Pol)

Simulation (Meso-NH)

(x) hail + graupel

(o) hail

graupel

hail

18:00 UT

19:00 UT

20:00 UT

rain rain

12

km

100 km

Hydrometeor type

(o) hail

(x) hail + graupel

hail + graupel

dry snow

rain

Pujol et al., 2005

Microphysical retrievals - IOP 3 (moderate convection)

18:10 UT

18:30 UT

Microphysical retrievals - IOP 3 (moderate convection)

hail + graupel

S-Pol retrieval Meso-NH simulation

snow snow

rain rain

Microphysical retrievals - IOP 8 (stratiform rain)

Meso-NH simulationS-Pol retrieval

rain

snow

melting snow

Medina et Houze, 2003

Microphysical budgets : Mean vertical distribution of the hydrometeors

Lascaux et al., 2005

graupel

IOP 2Aice

snow

hail

cloudrain

IOP 8

cloudrain

snow

IOP 3

ice

rain

IOP 2A IOP 3 IOP 8

Microphysical budgets : mean vertical distribution of the different processes

max : 135 mm

max : 25 mm

m mm

Quasi-stationnary MCS 13-14 Oct. 1995

Cumulated precipitation 01 UTC to 06 UTC the 14th Oct. 1995

MESO-NH, x=10km

max: 31 mm

MESO-NH, x=2.5kmOBSERVATIONS

(Ducrocq et al, 2002)

Initial conditions: ARPEGE analysis at 18UTC

mMESO-NH, x=2.5km

Initialisation Ducrocq et al

(2000)’s

max : 99 mm

Sensitivity to initial conditions Sensitivity to initial conditions

+Nîmes

+Nîmes

Observations

Nîmes radar

Raingauges

Initial Conditions : ARPEGE analysis12UTC, 08/09/02

+

MESO-NH (2.5km)

12-h accumulated précipitation from 12 UTC, 8 Sept to 00 UTC, 9 Sept 2002

Gard flash-flood (8-9 Sept.2002)Initial

Conditions : Ducrocq et al (2000) Initialisation12UTC, 08/09/02

+

(Ducrocq et al, 2004)

Ducrocq V, F.Bouttier Météo-France SRNWP/Met Office/Hirlam workshop on Variational Methods Exeter (UK) 15-17 Nov 2004

TROCCINOX 2005

Chaboureau et al., 2005

Méso

-NH

Obse

rvati

on

Tb 10.8 m Diff 8.7 - 10.8 m

CirrusConvection

Geophysica

The approach Model towards Satellite to validate the cloud coverage

Stratocumulus : Capped BL

When the CBL is blocked by an anticyclonic subsidence

FIRE 1 case of EUROCS : Forcing terms : a LS subsidence + cooling (dl/dt<0) and moistening (dqt/dt>0) under the inversion to balance the subsidence

alt

itu

de (

m)

Cloud water mixing ratio (kg/kg)

Min = 0.025 g/kg

Max = 0.6 g/kg

0h 12h 0h 12h 0h

LES simulation of the diurnal cycle (x=50m)

Observations of the base and the top cloud layer Sandu et al., 2006



Sc)Sc)• CyclonesCyclones • Coupling with the surface Coupling with the surface • Coupling with other models (hydrology, Coupling with other models (hydrology,



Simulation of cyclone : case of Dina7800 km, x=36km

1944 km , x=12km

720 km , x=4km

3600 km

Automatic method of Initialization : Filtering/Bogussing

Barbary et al.

Simulations CEPMMT : trajectoires 22/01/02 00 UTC

Barbary et al.

Évolution en intensité( a ) Minimum de pression (MSLP)

920

930

940

950

960

970

980

990

0 6 12 18 24 30 36 42

échéance (heures)

MS

LP

(h

Pa)

( b ) Vent maximum à 10 mètres

0

10

20

30

40

50

60

70

0 6 12 18 24 30 36 42

échéance (heures)

Vm

ax (

m/s

)

( c ) Rayon de vent maximum (RMW)

0255075

100125150175

0 6 12 18 24 30 36 42

échéance (heures)

RM

W (

km)

Best Track CEP Prévision

Méso-NH CEP 36km Méso-NH CEP 4km Barbary et al.

Vertical cross-sections at x=4km

K

m/s

K

m/s

TC

Lq

EPe.

Horizontal wind

S-N W-E

Barbary et al.

Fine scale structure (1 km)le 22 janvier 17h10-17h20-17h30

dBZ

10-3s-1

Radar reflectivity

Relative vorticity



Sc)Sc)• Cyclones Cyclones • Coupling with the surfaceCoupling with the surface • Coupling with other models (hydrology, Coupling with other models (hydrology,



LakeTownSeaNature

Méso-NH AROME Arpège / Aladin

SURFACE

EXTERNALIZED SURFACE :

Exchange of data flow at each time step between the 2 models

Atmosphere forcing Sun position Radiative fluxes

albedo emissivity radiative temperature

fluxes : Momentum, heat, water vapor, CO2, chemistry

Boundary conditions for turbulence and radiative schemes

Presentation of P.Le MoignePresentation of P.Le Moigne

Set-up :

4 grid-nesting models from regional to city scale, with respective resolutions of 12 km, 3 km, 1 km and 250 m

3D Meso-NH simulations (Lemonsu et al., 2004, 2005)

500

400

300

200

100

50

(m)

600

700

France

Mer Mediterranée

2000

1000

500

200

100

50

(m)

Mer Mediterranée

2000

1000

500

200

100

50

(m)

Marseille

Mer Mediterranée

2000

1000

500

200

100

50

(m)

Marseille

Model 1

Model 2

Model 3Model 4

Chaine de l’Etoile

Mont St-Cyr

MarseilleveyrePuget

N.D. de la Garde

Validation of

simulations

at regionalregional scale

Validation of

simulations

at urbanurban scale

Mediterranean Sea

Marseille veyre

Massif du Puget

City centre

500

1000

1500

2000

2500

Alt

itude (

m)

21 juin

22 juin

23 juin

24 juin

25 juin

26 juin

Obs

Model

500

1000

1500

2000

2500

Alt

itude (

m)

St Rémy

Radiosoundings

St Rémy de Provence

Regional validation

Thermodynamic structures

Urban network

Model

Air temperature inside the streets

26 June 2001, 1400 UTC

Lemonsu et al., 2005a

6 m s-1420-2-4-6

26 June 2001, 1400 UTC

B

C

D

A

TWL

B

C

D

A

Model

VDOL

City cente

r0 2 4 6 0 2 4 6Distance (km) Distance (km)

VDOL

City cente

r

0.5

1.0

1.5

2.0

2.5

Alt

itude (

km

)

Lemonsu, Bastin et al., 2005b

500

400

300

200

100

50

ZS (m)

Marseilleveyre

190o

Puget MassifCNRS

(Radar)

3 km

VAL (Lidar)

OBS (Radar)

Etoile Massif

Comparison with transportable wind lidar (TWL)

W

VAL

OBS

CNRS

m s-1

Puget Massif

Marseilleveyre

City centre

VAL

OBS

CNRSPuget Massif

Marseilleveyre

City centre

z = 400 m AGL

z = 50 m AGL

West SSB

South SSB

South-East DSB

Atmospheric boundary layerHorizontal wind field

26 June 2001, 1400 UTC

Without townRealistic

TKE

x=1km

Simulation on PARISDAY

Lemonsu et Masson (2001)

Nocturnal UBL

Without townRealistic

Lemonsu et Masson (2001)

Masson (2001)

Formation of fog

CarboEurope/RE : modélisation Meso-NH/ISBA-A-gsC.Sarrat et al., CNRM/GMME/MC2

Modelisation of the atmospheric CO2 in interaction with the surface : coupling of CO2 in Meso-NH with CO2 fluxes of

ISBA-A-gs • Improvement of the exchanges surface-atmosphere • Improvement of water cycle/ evapotranspiration• Improvement of the PBL representation• Regional budget of CO2 atmosphérique• Inversion of CO2 concentrations to identify

sources/sinks of CO2 (Thèse T. Louvaux)

ISBA-A-gs

Met. forcing LE, H, Rn, W, Ts…

CO2 Flux[CO2]atm

Anthropogenic

Sea

Meso-NH Surface

Modélisation 3-D : Configuration

Domaine : France (900x900 km)Résolution horizontale : 10 kmPas de temps : T = 10 s

Domaine : Landes (320x250 km)Résolution horizontale : 2.5 kmPas de temps : T = 5 s

Nesting 2 ways Surface : ISBA-A-gs (Ecoclimap) Vertical grid : 60 levels (0 -14000m)

Modélisation 3-D : Résultats

RN

LE

H

SFCO2

[CO2]

CarboEurope/RE : modelisation Meso-NH/ISBA-A-gs and atmospheric CO2

[CO2] simulated at 15H (june 2001)Advection + Assimilation + vertical mixing [CO2] decrease

00H : Advection + Respiration + cooling [CO2] increase

Coupling of Meso-NH with other models (Hydrology,

Dispersion)

VidourleVidourle

GardGard

CèzeCèze

ArdècheArdèche• TOPMODEL (Beven and Kirkby,

1979) distributed hydrologic model with one model by basin : 9 basins (200-2200 km²)

• Objectives :- Flow and rapide flood forecasts- Retroaction of the hydrology on the atmosphere- Available for AROME

HYDROLOGY : Development of the coupling Meso-NH-ISBA-TOPMODEL

K.Chancibault et al., CNRM/GMME/MICADO

Strategy of the coupling

Meso-NH ou Arome

ISBA TOPMODEL

Module de routage

t = 5 minx = 2-3 kmL = 1000 km

t = 5 minx = 2-3 kmL = 1000 km

t = 1hx = 50 mL = 1 km

Wmob

flux

120km, x=2km

30km, x=500m

Dispersion with passive tracers : case of AZF

Tulet et Lac (2001)

Vertical cross-section

30min after the release

the release

SPRAY• Lagrangian particle model•At least 10000 particles released •Advection+Turbulence+random• Applied to the 2 Meso-NH grids

PERLEPERLE (PProgramme d’EEvaluation des RRejets L Locaux d’EEffluents)

Dispersion

Meso-NH • 2 grids (Regional x=8km, L=240km/ Local x=2km, L=60km)• 36 levels until 16km• ALADIN initialization and coupling

Meso-scale meteorology

Will be exported to AROME

Modelling system for environmental emergency

Concentrations à Z=10m Concentrations à Z=800m

Source

BLAG NAC

CO LO M IERS

M UR ET

TO ULO USE

TO UR NEFEUILLE

C o u p e h or izon ta le a 10 m

C on c (g /m 3) le 21 .09 .20 0 1 a 0 8 h 2 0 U T C

1E -006

1E -005

1E -004

1E -003

1E -002

0m 500 0m 100 00m 150 00m 200 00m

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE

C o u p e h o r izo n ta le a 1 0 m

C on c (g /m 3) le 21 .09 .20 0 1 a 0 8 h 2 5 U T C

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

1 E -0 0 2

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE


C on c (g /m 3) le 21 .09 .20 0 1 a 0 8 h 3 0 U T C

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

1 E -0 0 2

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE


C on c (g /m 3) le 21 .09 .20 0 1 a 0 8 h 4 0 U T C

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

1 E -0 0 2

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAG NAC

CO LO M IERS

M URET

TO ULO USE

TO URNEFEUILLE


C o n c (g /m 3 ) le 2 1 .0 9 .2 0 0 1 a 0 8 h 5 0 U T C

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

1 E -0 0 2

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAG NAC

CO LO M IERS

M UR ET

TO ULO USE

TO UR NEFEUILLE

C o u p e h or izon ta le a 10 m

C on c (g /m 3) le 21 .09 .20 0 1 a 0 9 h 0 0 U T C

1E -006

1E -005

1E -004

1E -003

1E -002

0m 500 0m 100 00m 150 00m 200 00m

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE

C o u p e h o r izo n ta le a 8 0 0 m

C on c (g /m 3) le 21 .09 .20 0 1 a 0 8 h 3 0 U T C

1 E -0 0 7

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE


C on c (g /m 3) le 21 .09 .20 0 1 a 0 8 h 4 0 U T C

1 E -0 0 7

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE


C on c (g /m 3) le 21 .09 .20 0 1 a 0 8 h 5 0 U T C

1 E -0 0 7

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE


C on c (g /m 3) le 21 .09 .20 0 1 a 0 9 h 0 0 U T C

1 E -0 0 7

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE


C on c (g /m 3) le 21 .09 .20 0 1 a 0 9 h 1 0 U T C

1 E -0 0 7

1 E -0 0 6

1 E -0 0 5

1 E -0 0 4

1 E -0 0 3

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Méso-NH + SPRAY

Temps de réponse=

25min

Source

BLAGNAC

CO LOM IERS

M URET

TO ULO USE

TOURNEFEUILLE


C T A

1 E -0 0 9

1 E -0 0 8

1 E -0 0 7

1 E -0 0 6

1 E -0 0 5

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

Source

BLAG NAC

CO LO M IERS

M URET

TO ULO USE

TO URNEFEUILLE


C T A

1 E -0 0 9

1 E -0 0 8

1 E -0 0 7

1 E -0 0 6

1 E -0 0 5

0 m 5 0 0 0 m 1 0 0 0 0 m 1 5 0 0 0 m 2 0 0 0 0 m

ATC (Atmospheric Transfert Coefficient) = Trajectory of the pollutant cloud

Case of AZF

DiagnosticsDiagnostics

• Budget (heat, momentum, microphysics species, Budget (heat, momentum, microphysics species, TKE) with masksTKE) with masks

• Diagnostic fields Diagnostic fields • Lagrangian trajectories Lagrangian trajectories (3 added prognostic fields) (3 added prognostic fields)

• Passive tracersPassive tracers• Comparison to observations Comparison to observations (Meso-NH tools : (Meso-NH tools :

Presentation of I.Mallet-N.Asencio)Presentation of I.Mallet-N.Asencio)

http://www.aero.obs-mip.fr/mesonh/doc.html/#lagrangian

http://www.aero.obs-mip.fr/mesonh/doc.html/#lagrangian

z=z-z0 after 30min

Orographic convection

17km

270km

Gheusi (2003)

Growing of a convective cell

10km

10km

Total water mixing ratio (vap+liq)Initially at z0=1500m

T=14min

Gheusi (2003)

+ Trajectory/Back-trajectory

Dynamics of a thalweg

Initial height z0 of particles currently at z=7000m

Initial latitude y0 of particles currently at =315K

Exemple obs2mesonh: T2MExemple obs2mesonh: T2M

Ouest Est

Coupe Horizontale K=20

Exemple obs2mesonh: réflectivité radar Exemple obs2mesonh: réflectivité radar RonsardRonsard

Coupe verticale : modèle + radar

dBz

Milan

Meso-scale modelling wind climatology

An alternative to the measurement = the meteorological models

Error of the climatology = Error of the model

Measurements at 10m height are used to evaluate the quality of the climatology

First solution An operational numerical weather prediction, with an important record : Aladin 5 ans (resolution 0.1°)

Methodology only for the mean wind speed (not for extreme winds, or another meteorological field)

• First step : Statistical selection of weather patternsClassification of weather patterns on 700hPa geopotential of ECMWF reanalyses (résolution 1°, 15 years) 19

classes, with a weight (occurrence)

Choice of the dates number 95 dates

Choice of the dates : Number of the dates proportional to the frequency

Second solution A mesoscale meteorological model (x=1-3 km), not yet operationnal

• Second step : Simulation of the selected dates with Meso-NH95 dates simulated (24h) with ALADIN initial and coupling fields

Wind climatology build up with the weighted function of each of the 19 weather patterns

Error of the climatology = Error of the model + Error of the statistical sample

Vosges, Forêt Noire : 1.2 km

Alpes du Nord 2 km

Alpes du Sud 2 km

Pourtour méditerranéen 3 km

Auvergne 2 km

Sud-Ouest 3 km

Geographical area with Meso-NH wind climatology

Limousin 1km

Bourgogne 2 km

Quiberon 1 km

Roses Aladin 3 ansMéso-NH 95 dates Measurements

North Alps

Méso-NH 95 dates

77

75

77

74

80

77

France (synop)

Vosges

Alpes du Nord (29 stations)

Alpes du Sud (26 stations)

Massif Central (67 stations)

Sud-Ouest (72 stations)

Méditerranéen (99 stations)

Obs 95 dates

88

92

91

90

88

87

Aladin 3-4 ans

80

72

62

63

69

80

71

Evaluation on Dry Convective boundary layer : CARBOEUROPE

Boundary Layer HeightMESONH vs RS La Cape Sud

0

500

1000

1500

2000

2500

0 500 1000 1500 2000 2500

observed

sim

ula

ted

25-may

26-may

27-may

31-may

06-june

07-june

08-juin

09-juin

10-juin

MESO-NH vs PIPER

La Cape Sud : Comparison Meso-NH/RS of BL height (parcel method) between 6 and 17UTC

Weak overestimation during the afternoon

Weak underestimation during the morning

Forecasts of Meso-NH (8km) in an operational mode during the experiment

AROME : Application of Researh to Operations at MEsoscale

Future non-hydrostatic model 2.5km resolution

Dynamics based on ALADIN-NH (semi-implicite, semi-lagrangian)

Data assimilation ALADIN 3D-VAR

Physics based on Méso-NH : microphysics ICE3, Turbulence 1D, shallow convection, externalised surface

http://www.cnrm.meteo.fr/aladin/aladin2/traceMP/AROMErunMP.html

Arome 60s

Case of Gard, initial Case of Gard, initial bogus bogus

Lame d’eau 12-22 Tu

radar de Nîmes

> 300 mm

Couplage : Aladin 3h Forecasts

MésoNH 4s

304 mm

274 mm

• MésoNH t= 4s , CPU = 24h20

• AROME t =60s, CPU = 2h30

Deep clouds

Cirrus clouds

BL clouds : Cu

Mainly driven by dynamics. Mixed-phase microphysicsGood results with AROME (no excessive W)

Depends on convective systems (anvils). Turbulence ice improves the life cycle. Improvement with tuning of microphysics.

-The CBR scheme enables to produce BL clouds. Countergradient (TOMs) insufficient.Improvement : Mass-Flux (Siebesman and Soares)-Subgrid condensation with ED+MF contribution

Larger cloud fraction. Variety of turbulence and stability profiles - Importance of entrainment. Improvement of Mixing length -Aerosol effects -

Transition to BL clouds. Turbulent mixing dominated by large-eddy transport and entrainment at the top.

Improvement : Countergradient (TOMs) versus EDMF (Siebesman and Soares)

Dry CBL

BL clouds : Sc

Stable BL and transition to neutral BL. Improvement of Mixing length. Microphysics and aerosols.

Fog

Imp

rovem

en

t of

Meso

-NH

ph

ysi

cs f

or

AR

OM

E

meso-nh model

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