1D Dice Experiment at Meteo-France and

LES preliminary result

E. Bazile, I. Beau, F. Couvreux and P. Le Moigne (CNRM/GAME)

DICE Workshop

Exeter 14-16 October 2013

DICE Workshop Exeter 14-16 October 2013

Outline

Physics package used in NWP and climate Sensitivity test : vertical resolution and time step Stage 2 results :

– Physics package: AROME, ARPEGE and ARPEGE-CLIMAT

– Impact of the soil type Preliminary LES results Questions …

DICE Workshop Exeter 14-16 October 2013

Operational Weather forecasting at Météo-France

July 2013

Global ARPEGE-IFS4-day forecasts every 6 hours dx=10 km on

France, 55km on Australia dt=514s Stretching factor c=2.4 and turning of the pole

over the zone of interestStretched vertical grid with 70 levels4DVar Inc Data Assimilation system

(T107 25iter and T323 30iter dx=60km)

Cloud Resolving Model AROME-France30 h forecasts every 6h

dx=2.5 km, 60 Levels, time-step=1mn (SL)3DVar Data Assimilation system (RUC3h)

DICE Workshop Exeter 14-16 October 2013

PHYSICS in ARPEGE/ALADIN/AROME

ARPEGE-Climat(AR5)

ARPEGE-NWP( 7.5 km)

AROME (NH)2.5km

Surface SURFEXwith ISBA

ISBA(Noilhan, Planton (89), Giard

Bazile (2000))

SURFEX with ISBA, TEB, Ecume,

etc

Turbulence TKE-2.0/Mellor-Yamada 82

(Ricard Royer-93) TKE (Cuxart et al 2000)

Mixing length Quadratic profile

(Lenderink and Holtslag, 2004)

Bougeault Lacarrere (89)

Modified by the shallow cloud thickness and deep

convection

Shallow Convection

TKE-2.0/Mellor-Yamada 82

(Ricard Royer-93) KFB (Bechtold et al 2001) PMMC09 (Pergaud et

al 2009)

Deep Convection Moisture Convergence (Bougeault 85) (v3 cy18)

Moisture Convergence (Bougeault 85)

Explicitly resolved

Clouds (PDF) f0, f1, f2 Bougeault (82) Smith (90) f0, f1, f2 Bougeault (82)

GWD Described in annexe of Catry et al. 2008 no

Microphysics Kessler-Smith (1990) Ql,Qi,Qr,Qs Lopez(2002) Bouteloup et al (2005)

Ql,Qi,Qr,Qs,QgPinty and Jabouille 1998

Radiation RRTM for LW (Mlawer et al. 1997) and Morcrette et al. 2001 for SW (6b)

DICE Workshop Exeter 14-16 October 2013

Sensitivity test: vertical resolution,time step (1)

• Vertical discretisation and time step:

• L70 operational vertical levels for ARPEGE time-step=600s

• L60 operational vertical levels for AROME (more levels in the PBL and lowest level at 10m) time-step=60s

•Stage 1b:

• ARPEGE physics L70 with 600s (close to oper dt=514,286s !)

• ARPEGE physics L70 with 60s

• ARPEGE physics L60 with 60s (AROME time step and vertical levels)

• AROME physics L60 with 60s (oper)

• AROME physics L70 with 60s

DICE Workshop Exeter 14-16 October 2013

Sensitivity test: vertical resolution,time step (2) (Night)

Theta at 15UTC Theta at 39UTC Theta at 63UTC

TKE at 15UTC TKE at 39UTC TKE at 63UTC

Why more TKE ?

DICE Workshop Exeter 14-16 October 2013

Sensitivity test: vertical resolution,time step (3) (Night)

The second night is more turbulent due to a sensible heat around 35 W/m2 and a friction velocity around 0.25 m/s more TKE

DICE Workshop Exeter 14-16 October 2013

Sensitivity test: vertical resolution,time step (4) (daytime)

Theta at 24UTC Theta at 48UTC

TKE at 24UTC TKE at 48UTC

DICE Workshop Exeter 14-16 October 2013

Sensitivity test: vertical resolution,time step (5)

PBL height (m)

•small impact between L70/L60 and time step for state variables.

•TKE is more sensitive and therefore the PBL height (computed with the TKE profile)

•The second night is more turbulent due to the forcing (sensible heat and friction velocity). Is it the same with the surface parameterization (stage 2) ?

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

• Ref : Initial state from SURFEX with the operational ECOCLIMAP soil characteristics and vegetation (Stage1a done by P. LeMoigne)

•Type 103: (grass 100%) Lai =1.8 d2=1.5m d3=2m, z0=0.04m Rsmin=40

•Type 108: (crops C3 90% and C4 10%) Lai=1.0 d2=1.5m d3=2m, z0=0.02, Rsmin=43

•AROME L60 (dt=60s)

•ARPEGE-NWP L70 (dt=600s)

•ARPEGE-NWP L70 (dt=60s)

•ARPEGE Climat (AR5) L70 (dt=600s)

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

Theta stage 2 at 24UTC

Theta stage 2 at 48UTC

ARPEGE-Climat AR5 is warmer near surface and colder above more mixing ?

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

Theta stage 2 at 24UTC

Theta stage 1b at 24UTC

Theta stage 1b at 48UTC

Theta stage 2 at 48UTC

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

Sensible Heat Latent Heat Ustar

Stage 2: with the operational soil characteristics from ECOCLIMAP (SURFEX) the latent heat flux is significantly increased ~200W/m2 instead of 50W/2 less sensible heat lower PBL height

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

• Ref : Initial state from SURFEX with the operational ECOCLIMAP soil characteristics and vegetation (Stage1a done by P. LeMoigne)

•Type 103: (grass 100%) Lai =1.8 d2=1.5m d3=2m, z0=0.04m Rsmin=40

•Type 108: (crops C3 90% and C4 10%) Lai=1.0 d2=1.5m d3=2m, z0=0.02, Rsmin=43

• Exp1: same as Ref except the soil depth d2=0.4m d3=0.6

• Exp2: bare ground with d2=0.4m d3=0.6

•AROME L60 (dt=60s)

•ARPEGE-NWP L70 (dt=600s)

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

Sensible Heat Latent Heat Ustar

With a smaller soil depth (root depth 40cm) the latent heat is lower (max 100W/m2) and the sensible heat is increased.

With bare soil, the latent heat is closer to the “forced” one, but the sensible heat is underestimated, too small z0 ? No significant impact on Ustar.

DICE Workshop Exeter 14-16 October 2013

Stage 2 results:

Theta at 24h Theta at 48h

Qv at 24h Qv at 48h

Theta at 39h

Qv at 39h

Ref experiment too moist and too cold

DICE Workshop Exeter 14-16 October 2013

LES Simulations of the DICE case: preliminary work

Model: Meso-NH (turbulence scheme : 3D- tke)Resolution: x=y=40m; 70 levels up to 2500m / 200 levels with z=12m Domain: 4 x 4 km² / 8 x 8 km²Surface fluxes imposed (set-up I) Duration: 24 hours

A global similar evolution between 1D and LES

DICE Workshop Exeter 14-16 October 2013

LES Simulations of the DICE case: preliminary work

Model: Meso-NH (turbulence scheme : 3D- tke)Resolution: x=y=40m; 70 levels up to 2500m / 200 levels with z=12m Domain: 4 x 4 km² / 8 x 8 km²Surface fluxes imposed (set-up I) Duration: 24 hours

A global similar evolution between 1D and LESPbm linked to reflecting waves at the top of the domain :

not enough levels in the upper domain

DICE Workshop Exeter 14-16 October 2013

LES Simulations of the DICE case: preliminary work

Tke at 15 UTC

Problem linked with waves ?

Tke is underestimated during the first nignt vs LES result. Well know problem (BLLAST and DomeC comparison).

In stage 2 (ref) , TKE is overestimated with ARPEGE near the surface and underestimated above 100m

Future work:- To analyze the sensitivity to resolution & domain size-> to define best configuration

DICE Workshop Exeter 14-16 October 2013

Conclusions & Perspectives

Results from ARPEGE-NWP and AROME have been provided for stage 1b, stage 2 and stage3a, with two vertical grid L70, L60 and dt=60s and/or 600s

ARPEGE-CLIMAT (AR5) will be send soon with the next version of ARPEGE-CLIMAT (similar to ARPEGE-NWP)

The initial soil moisture for stage 2 is really important and strongly dependant of the the soil depth (root depth) used during stage 1a, therefore the “operational” soil characteristics used for ARPEGE/AROME and Meso-NH increase the latent heat flux and is responsible of the cold bias compared to stage1b

TKE in AROME/ARPEGE is probably underestimated in stable conditions and during the sunset not enough mixing

Runs the LES with a surface scheme initialized as the 1D runs of MNH and AROME/ARPEGE (same surface scheme= SURFEX)

Use the simulation to analyze the processes at play during the whole diurnal cycle (tke budgets, turbulence characteristics,…) and how the coupling with the surface impact them