Using BRAMS in simulating mesoscale processes in Argentina

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1 Using BRAMS in simulating mesoscale processes in Argentina Matilde Nicolini Departamento de Ciencias de la Atmósfera y los Océanos. UBA. CIMA- Centro de Investigaciones del Mar y la Atmósfera. CONICET-UBA

2 Ultimate goal: Improve short range weather forecast in Argentina Focus of presentation in: Evaluate the capability of BRAMS to properly reproduce conditions and features at different scales prior and during severe storm events Improvement in detail analysis of physical interactions between moisture transport, precipitation and evolution of the South American LLJ, through downscaling and assimilation of field campaign observations

3 South American low-level level Jet Experiment (SALLJEX) 15 November February 2003 Field components: Precipitation network NOAA-P3 Aircraft missions Upper-air sounding network (RAOBs and pibals) SOP s: 2 RAOBS daily (06 and 18 UTC) IOP s: 3-4 RAOBS and/or 8 PAOBS/day

5 Piura Pucallpa Cruzeiro Rio Branco Ica Cobija Trinidad Vilhena Puno Santa Cruz Roboré Villamontes Mariscal Dourados Santiago del Estero Chamical Salta JVG Asunción Pampa Foz de Iguazu Tostado Resistencia Córdoba Parana

6 Zipser et al., 2006 Extreme values of variables from 7 years TRMM database used as proxy to identify intense convection

7 Hailstorm in Mendoza (February 14th 2005) Tornado generating storm in Northeastern Argentina (April 28th 2001) Mesoscale convective system (December ) Environmental characterization prior and during MCSs development during a SALLJ event using downscaling and data assimilation (February )

8 Hailstorm simulation in Mendoza Matilde Nicolini,Yanina García Skabar, Graciela Ulke and Paola Salio, 2005

Vertical coordinate SHAVED ETA 30 atmospheric levels - 9 soil levels Horizontal resolution: 50, 12.5, 3.125 and 0.

9 Vertical coordinate SHAVED ETA 30 atmospheric levels - 9 soil levels Horizontal resolution: 50, 12.5, and 0.78 km 12 hours simulation 4 nested Domains Grell convection parameterization only at 50 km resolution Microphysics: two moments scheme Initial and boundary conditions: GDAS analyses from NCEP

10 BRAMS 17 UTC 20 UTC 22 UTC Vertically integrated cloud water species Radar reflectivity (observations) +70 dbz

11 32.7º S - 21 UTC 33.05º S - 21:30 UTC BRAMS Vertical cross sections along NW-SE transect 33.27º S - 21:30 UTC Zr (shaded), q(graupel+hail)contours,

12 BRAMS Tornado simulation Matilde Nicolini, Marcela Torres Brizuela and Yanina García Skabar, 2005

13 Vertical coordinate SHAVED ETA 30 atmospheric levels - 9 soil levels Horizontal resolution: 50, 12.5, and 0.78 km 12 hours simulation 4 nested Domains Grell convection parameterization only at 50 km resolution Microphysics: bulk water scheme Initial and boundary conditions: GDAS analyses from NCEP

14 19:30 UTC BRAMS Clouds and vertical velocity 20 UTC BRAMS accumulated precipitation UTC

15 April 28th 20 UTC W (solid lines), wind vectors, p*(blue) at 95,4m P* 1725m -red 6660m -blue mesocyclone 850 hpa W and Zr (shaded) Hook-echo Max. cyclonic ζ Vorticity Cloud (shaded)

16 28.19ºS - 20 UTC Cloud and total precipitating categories Precipitation Cloud, motion and vertical vorticity vertical alignement (tornadogenesis signal)

17 Mesoscale convective system simulation (December ) Juan Ruiz, Celeste Saulo, Yanina García Skabar and Paola Salio, 2005 IR RADAR B A A Región con ecos débiles Banda brillante Superficie 15 Km B

18 Vertical coordinate Sigma Z (RAMS 4.3) 30 atmospheric levels - 9 soil levels Horizontal resolution: 80 and 20 km 48 hours simulation Microphysics: bulk water scheme Grell convection parameterization activated at both domains Initial and boundary conditions: GDAS analyses from NCEP

19 TMI RADAR PR RAMS RAMS Vertically integrated total condensate (shaded) Precipitation rate mm/hr (contours) 06 UTC Dec 19th 2002

20 RAMS 24-hour total accumulated precipitation in mm Dec 2002 Observed CMORPH algorithm estimates

21 Resistencia 06UTC 19 Dec Santiago del Estero GDAS (triangles), RAMS (circles) rawins (no mark)

22 Characterization of environment prior to the development of a sequence of subtropical MCSs during a SALLJ event using downscaling and data assimilation (February ) Borque, Salio, Vidal, Garcia Skabar and Nicolini, 2006)

23 Cross section at 25ºS Feb 06 to 07 15UTC θ, wind barbs and V component

24 Observed daily accumulated precipitation (upper panels) and modeled by BRAMS (lower panels) White areas indicate lack of data

Downscaling and data assimilation Vertical coordinate SHAVED ETA 30 atmospheric levels - 9 soil levels Horizontal resolution: 80 and 20 km Temporal resolution 3 hours 20 km 80 km Grell convection

25 Downscaling and data assimilation Vertical coordinate SHAVED ETA 30 atmospheric levels - 9 soil levels Horizontal resolution: 80 and 20 km Temporal resolution 3 hours 20 km 80 km Grell convection parameterization activated at both domains Operative network and special data from SALLJEX assimilated during a 3 months period (November 15th 2002 to February 15th 2003) Initial and boundary conditions: GDAS analyses from NCEP

26 Lower RMSE when data are assimilated DWSC1-ETA DWSC2-ETA 2. 5 DWSC1-SIGMA DWSC2-SIGMA GDAS

27 Summary The promising results in a generating tornado storm and a hailstorm suggest that BRAMS is capable to simulate severe convective events over Argentina. This satisfactory performance of the model encourages a thorough analysis of other events to progress in the understanding of preconditioning and triggering mechanisms of convection. Downscaling and data assimilation provides a set of enriched analyses to characterize different case studies and understanding of convective related phenomena. Current BRAMS implementation in real time at UBA will provide further evaluation in forecast mode under a variety of synoptic conditions and using a more general configuration.

28 Acknowledgments: This research is supported by UBA grant X266 and ANPCyT grant Nº PICT the collaborative program IAI-CRN 55. SALLJEX was supported by PACS-SONET network, FAPESP grant 01/ (Brazil), NSF ATM , NASA NAG NOAA PID and NA03OAR

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