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This study compares observed radar data with simulation results from the Meso-NH model to analyze the time evolution of precipitation during Intensive Observation Period (IOP) 8B. The impact of turbulence schemes, initial and forcing conditions, and model resolution are also examined. The evaluation includes raingauges, Meteosat IR observations, and an isolated thunderstorm forecast.
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ANR Agence nationale de la recherche COPS - FRANCE LA, Toulouse IPSL, Paris CNRM, Toulouse LaMP, Clermont-Ferrand
Meso-NH IOP 8B COPS - France • Instrumentation on supersite V • Lidar Juan Cuesta • Radar Joël Van Baelen • Reinforcement of the GPS network • Cédric Champollion • Safire Falcon / Leandre II operation • Cyrille Flamant • Numerical modelling • Jean-Pierre Chaboureau • Evelyne Richard • High-resolution assimilation • Pierre Brousseau • Olivier Caumont Other case studies …see Chaboureau
DLR Poldirad at Waltenheim sur Zorn 14:40 UTC 15:00 UTC 14:20 UTC 14:00 UTC 15:20 UTC 15:40 UTC 16:00 UTC IOP 8B : 15 July 2007
12:15 – 13:00 13:15 – 14:00 14:15 – 15:00 15:15 – 16:00 Time evolution : Observation versus simulation Montancy radar observations (2dBz contour – PPI 1°) Meso-NH (2km - ECMWF driven) (0.1 mm precip contour)
12:15 – 13:00 13:15 – 14:00 14:15 – 15:00 15:15 – 16:00 Time evolution : Observation versus simulation Montancy radar observations (2dBz contour – PPI 1°) Meso-NH (2km - ARPEGE driven) (0.1 mm precip contour)
12:15 – 13:00 13:15 – 14:00 14:15 – 15:00 15:15 – 16:00 Time evolution (close up view) : Observation versus simulation Montancy radar observations (2dBz contour – PPI 1°) Meso-NH (2km - ECMWF driven) (0.1 mm precip contour)
12:15 – 13:00 13:15 – 14:00 14:15 – 15:00 15:15 – 16:00 Time evolution : Observation versus simulation Montancy radar observations (2dBz contour – PPI 1°) Meso-NH (500m - ECMWF driven) (0.1 mm precip contour)
2km Meso-NH simulation : 13:00 UTCSurface streamlines / CAPE / precipitation ( ) ECMWF ARPEGE
2km Meso-NH simulation : 14:00 UTCSurface streamlines / CAPE / precipitation ( ) ECMWF ARPEGE
Vertical cross sections of reflectivity along storm propagation Meso-NH (2km - ECMWF driven) Meso-NH (2km - ARPEGE driven)
Conlusion • High sensitivity to initial conditions • More convection with ARPEGE CI than with ECMWF CI (… with the truth in between!) • Earlier triggering with ARPEGE CI (too early) but a more realistic life cycle • Major role of the low-level convergence • No significant improvement when : • Resolution is increased from 2km to 500m (Triggering occurs too much upwind • 3D turbulence is accounted for (very weak impact) More on that topic : Trentmann (U. Mainz) and Cardwell (U. Manchester)
12:15 – 13:00 13:15 – 14:00 14:15 – 15:00 15:15 – 16:00 15/07/07 Montancy Radar Observations Meso-NH simulation (ARPEGE) Meso-NH simulation (ECMWF)
12:15 – 13:00 13:15 – 14:00 14:15 – 15:00 15:15 – 16:00 Time evolution : Impact of the turbulence scheme (1D/3D) Meso-NH (2km – 1D turbulence) (0.1 mm precip contour) Meso-NH (2km – 3D turbulence) (0.1 mm precip contour)
12:15 – 13:00 13:15 – 14:00 14:15 – 15:00 15:15 – 16:00 Time evolution : Impact of the initial / forcing conditions Meso-NH (2km - ECMWF driven) (0.1 mm precip contour) Meso-NH (2km - ARPEGE driven) (0.1 mm precip contour)
12:15 – 13:00 13:15 – 14:00 14:15 – 15:00 15:15 – 16:00 Time evolution : Impact of the resolution (2km/ 500m) Meso-NH (500m – ECMWF driven) (0.1 mm precip contour) Meso-NH (2km - ECMWF driven) (0.1 mm precip contour)
Meso-NH Forecasts http://mesonh.aero.obs-mip.fr/mesonh/cops/ • 3 domains (32, 8, and 2 km) with 2-way interaction. • Vertical grid with 50 levels up to 20 km with a grid length varying from 60 m to 600 m. • Initial and coupling fields with ECMWF operational forecasts • 30 h forecast starting at 00 UTC • Parameterization schemes: • o 1.5-order turbulence scheme • o ECMWF radiation package • o ISBA surface scheme • o Mixed-phase bulk microphysics: cloud, rain, ice, snow, graupel, and hail (hail is simulated for the inner model only) • o Deep and shallow convection scheme for the 32 and 8 km models only
Outline • Basic model evaluation • Raingauges precipitation measurements • Meteosat IR observations • An example of an isolated thunderstorm forecast • 15 July
24h precipitation (P30h – P06h): 04 July 2007 (J185) • Precip evaluation : • BW stations • MF automatic stations • Model fields interpolated at rain gauge location Thanks to M. Kunz and P. Limnaios
Time evolution of the spatially averaged 24h precip. P30h-P06h (mm) Julian day (July/August)