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1D Dice Experiment at Meteo-France and LES preliminary result

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. Outline. Physics package used in NWP and climate Sensitivity test : vertical resolution and time step

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1D Dice Experiment at Meteo-France and LES preliminary result

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  1. 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

  2. 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

  3. Operational Weather forecasting at Météo-France July 2013 Cloud Resolving Model AROME-France 30 h forecasts every 6h dx=2.5 km, 60 Levels, time-step=1mn (SL) 3DVar Data Assimilation system (RUC3h) Global ARPEGE-IFS 4-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 interest Stretched vertical grid with 70 levels 4DVar Inc Data Assimilation system (T107 25iter and T323 30iter dx=60km) DICE Workshop Exeter 14-16 October 2013

  4. PHYSICS in ARPEGE/ALADIN/AROME DICE Workshop Exeter 14-16 October 2013

  5. 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

  6. 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

  7. 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

  8. Sensitivity test: vertical resolution,time step (4) (daytime) Theta at 48UTC Theta at 24UTC TKE at 24UTC TKE at 48UTC DICE Workshop Exeter 14-16 October 2013

  9. 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

  10. 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

  11. Stage 2 results: Theta stage 2 at 48UTC Theta stage 2 at 24UTC ARPEGE-Climat AR5 is warmer near surface and colder above more mixing ? DICE Workshop Exeter 14-16 October 2013

  12. Stage 2 results: Theta stage 2 at 48UTC Theta stage 2 at 24UTC Theta stage 1b at 48UTC Theta stage 1b at 24UTC DICE Workshop Exeter 14-16 October 2013

  13. Stage 2 results: DICE Workshop Exeter 14-16 October 2013

  14. Stage 2 results: DICE Workshop Exeter 14-16 October 2013

  15. 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

  16. 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

  17. 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

  18. Stage 2 results: Theta at 48h Theta at 24h Theta at 39h Qv at 39h Qv at 48h Qv at 24h Ref experiment too moist and too cold DICE Workshop Exeter 14-16 October 2013

  19. 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 km² Surface fluxes imposed (set-up I) Duration: 24 hours A global similar evolution between 1D and LES DICE Workshop Exeter 14-16 October 2013

  20. 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 km² Surface fluxes imposed (set-up I) Duration: 24 hours A global similar evolution between 1D and LES Pbm linked to reflecting waves at the top of the domain : not enough levels in the upper domain DICE Workshop Exeter 14-16 October 2013

  21. LES Simulations of the DICE case: preliminary work 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 Tke at 15 UTC DICE Workshop Exeter 14-16 October 2013

  22. 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 DICE Workshop Exeter 14-16 October 2013

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