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
Outline AROME configuration at HMS Interaction of PBL turbulence and deep convection Case study One-month period SAL verification Conclusions and Outlook
AROME configuration AROME is operational at HMS since January 2011 2.5 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)
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:
Case study: 2010-07-22 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)
Low clouds 1h prec. 2010-07-22 06 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 07 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 08 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 09 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 10 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 11 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 12 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 13 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 14 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
Low clouds 1h prec. 2010-07-22 15 UTC no_ no_ MSG Cloudiness MSG Vis. Radar prec.
2010-07-22 - Profiles Domain averaged vertical profiles for 2010-07-22 10 UTC : stronger PBL mixing damps the small Interaction of PBL turbulence and convection in AROME convective cells
One-month period 2010-07-17 2010-08-17 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
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
SAL verification
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
SAL verification: Results
SAL: number of objects CBR + Kain-Fritsch Large overestimations of the object number are associated with anticyclonic conditions The version also slightly overestimates
Diurnal cycle of precipitation
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
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
Thank you for your attention!