Interaction of boundary-layer turbulence and convection in the AROME model: Preliminary results

Transcription

1 Interaction of boundary-layer turbulence and convection in the AROME model: Preliminary results Balázs Szintai Hungarian Meteorological Service COST ES0905 Workshop Cambridge, England 23 March 2010

2 Outline AROME configuration at HMS Interaction of PBL turbulence and deep convection Case study One-month period SAL verification Conclusions and Outlook

3 AROME configuration AROME is operational at HMS since January km horizontal resolution 60 vertical levels 4 runs daily (+36 hours) Model domain covers Hungary (larger domain is tested) Boundary conditions from ALADIN (IFS LBC is tested)

4 AROME configuration Currently: dynamical adaptation (cycling of hydrometeors and TKE) Deep convection is supposed to be resolved explicitly PBL/Shallow convection Until September 2010: CBR + Kain-Fritsch After September 2010:

5 Case study: Anticyclonic situation, weak large scale forcing Shallow convection during the morning with a transition to medium strength thunderstorms during late afternoon 3 experiments: CBR + Kain-Fritsch ( no_ ) Only CBR ( ) Simulation starts at 00 UTC (initialized from IFS)

6 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

7 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

8 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

9 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

10 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

11 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

12 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

13 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

14 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

15 Low clouds 1h prec UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.

16 Profiles Domain averaged vertical profiles for UTC : stronger PBL mixing damps the small Interaction of PBL turbulence and convection in AROME convective cells

17 One-month period Period with a lot of convective precipitation (both frontal and flat) AROME setup: IFS coupling Larger domain CBR+Kain-Fritsch vs. Verification against radar : SAL

18 SAL verification Objective verification using radar precipitation Defining objects in the model and in the radar field Dynamical threshold (Pmax/15) No association of the objects Three independent components S Structure A Amplitude L Location

19 SAL verification

20 SAL verification: Results CBR + Kain-Fritsch Problem: the SAL method is not sensitive to the number of and convective Interaction of PBL turbulence convection in AROME cells

21 SAL verification: Results

22 SAL: number of objects CBR + Kain-Fritsch Large overestimations of the object number are associated with anticyclonic conditions The version also slightly overestimates

23 Diurnal cycle of precipitation

24 Conclusions The choice of the PBL scheme has a significant impact on the resolved deep convection in AROME The higher PBL mixing reduces the number of cells and improves the timing of convection Current AROME setup: still too many cells and overestimation of precipitation

25 Outlook Test the third order moment scheme (Tomas and Masson, 2006) available in the AROME code Sensitivity tests: Horizontal resolution Horizontal diffusion Incorporate the number of cells in the SAL verification

26 Thank you for your attention!