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Emmanuel Rivière (1), V. Marécal (2), and contribution from the HIBISCUS/TROCCIBRAS participants

Modeling deep convection and chemistry in the continental tropics. Emmanuel Rivière (1), V. Marécal (2), and contribution from the HIBISCUS/TROCCIBRAS participants 1 GSMA/ CNRS and Université de Reims Champagne-Ardenne, France 2 LPCE/ CNRS and Université d’Orléans, France. Outline.

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Emmanuel Rivière (1), V. Marécal (2), and contribution from the HIBISCUS/TROCCIBRAS participants

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  1. Modeling deep convection and chemistry in the continental tropics Emmanuel Rivière (1), V. Marécal (2), and contribution from the HIBISCUS/TROCCIBRAS participants 1 GSMA/ CNRS and Université de Reims Champagne-Ardenne, France 2 LPCE/ CNRS and Université d’Orléans, France

  2. Outline •  Introduction • +What drives the UT/TTL air composition when convection occurs ? • +What is specific to continental deep convection ? • (with respect to oceanic deep convection) • Review : continental tropical campaigns / modeling tools •  3D mesoscale Modelling in the Frame of Hibiscus •  Conclusion

  3. waves « overshoot » Emissions slow ascent Vertical transport STE LNOx O3 Aqueous / ice chemistry (+ scavenging) Additional O3 production scavenging emissions Introduction What drives the composition of the upper troposphere and the TTL when deep convection occurs ? stratosphere UTLS 17 km TTL tropopause Homogeneous chemistry 11 km deep convection free troposphere LNOx Boundary layer 0 km Mid-latitudes Tropics

  4. Emissions Homogeneous chemistry Aqueous / ice chemistry (+ scavenging) Vertical transport by deep convection STE LNOx Introduction Modeling the chemical composition of the continental tropics need to account for all these processes. These processes occur both over the oceans and the continents

  5. What is specific to continental deep convection ? • (with respect to maritime deep convection) • Emissions at the surface : • Continental : NOx, VOCs, CO +…. • Ocean (clean atmosphere) +sea salt aerosols • Type of convection (organized or not) : • - convection more severe over the continents Higher altitude (with possibly higher LNOx production) • - Overshoot occurrence mainly above continents (direct effect of deep convection on the LS composition ?)

  6. What is specific to continental deep convection ? (with respect to maritime deep convection) #2 Overshoot occurrence Liu and Zipser, JGR, 2005 from TRMM observations ‰ Higher convection over continents. Overshoots mainly above continents.

  7. Emissions VOCs, NOx, CO… Vertical transport by deep convection Higher STE Overshoots more likely LNOx Enhanced production because of a more severe convection Introduction Modeling the chemical composition of the continental tropics need to account for all these processes. Homogeneous chemistry Aqueous / ice chemistry (+ scavenging)

  8. Emission data to be used in modeling studies Global emissions data from EDGAR, GEIA, RETRO • Temporal resolution : annually (EDGAR), Seasonly/annually (GEIA), monthly (RETRO) • Resolution 1° x 1° EDGAR and GEIA 0.5° x 0.5 for RETRO • Discrimination anthropogenic/biogenic : importance for biomass burning / wet season EDGAR

  9. Impact of the emissions on the UT composition Cloud scale simulations with RAMS-chemistry 50 km x 50 km grid 1km x 1km resolution 3h simulation • Emission from EDGAR : • Values from Sao Paulo • Values from Bauru • state of Sao Paulo (~10 • times less)

  10.  Intro : • +What drives the the UT/TTL air composition when convection occurs ? • +What is specific to continental deep convection ? • (with respect to oceanic deep convection) • Review (non-exhaustive) : continental tropical campaigns / modeling tools •  3D mesoscale Modelling in the Frame of Hibiscus •  Conclusion

  11. aircrafts Balloons, sondes A brief review (not exhaustive) Field Campaigns in the continental Tropics • TRACE-A, (mostly oceanic, continental in Southern Africa) • ABLE-2 Central Brazil dry and wet season : O3, CO, NO, PAN. • TROPOZ South America, O3, NO, CO. • Measurements onboard commercial aircraft O3 and H2O MOZAIC over Brazil up to 10-12 km (FranckfurtSao Paulo) • SHADOZ (O3 sondes in the tropics, continental sometimes) • HIBISCUS/TROCCINOX/TROCCIBRAS – TROCCINOX 2 Balloon and aircraft plateforms. O3, H2O, CH4, NO2, BrO, NOx and NOy CO2

  12. A brief review #2 Fields Campaign in the continental Tropics Lack of data over the continental tropics especially during the wet season Emmons et al., JGR, 2000. O3 airborne measurements 6-8 km

  13. AMMA West Africa during the monsoon + SCOUT-O3 Summer 2006. Aircrafts and balloons : O3, H2O, CH4, NOx, NOy, VOC. A brief review #3 Fields Campaign in the continental Tropics to come • TERESINA SCOUT-O3 September October 2007 over equatorial Brazil during the transition period : biomass burning + deep convection. Balloon : O3, H2O, CH4, NOy, NMVOC, Cly

  14. A brief review modeling tools • Large numbers of modeling approach 1D, 2D, 3D… : choice depends on the process to study • Coupling between microphysics/dynamics/chemistry is expensive  cloud scale studies or off-line chemistry • Cloud scale studies are very useful for larger scale studies subgrid parameterization • Computing efficiency is increasing  full regional scale studies dynamics/microphysics/chemistry are now possible. New point of view

  15. A brief review modeling tools • 3D modelling with chemistry : regional and global scale  3D Mesoscale modelling with on-line chemistry. Marécal et al., ACP, 2006 and Rivière et al., ACP 2006. Pre-HIBISCUS and HIBISCUS campaign, Brazil (continental tropics during the convective season).  Similar tools : Meso-NH chemistry to be run for the AMMA campaign Catt-BRAMS to be run for the Teresina campaign + …  Labrador et al GRL (2004) : impact of LNOx at global scale

  16.  Intro : • +What drives the the UT/TTL air composition when convection occurs ? • +What is specific to continental deep convection ? • (with respect to maritime deep convection) • Review (non-exhaustive) : continental tropical campaigns / modeling tools •  3D mesoscale Modelling in the Frame of Hibiscus •  Conclusion

  17. 3D mesoscale Modelling in the Frame of Hibiscus The RAMS chemistry model : • Mesoscale model (Colorado State University) with on-line chemistry. Nested grid simulation possible. • Grell convection parameterization (Thanks to S. Freitas) • Microphysics with 7 types of hydrometeors : liq droplet, rain, pristine ice, Hail, Graupel, Agregates, Snow. • Gas phase chemistry : 30 species and 70 reactions. Simplified scheme from MOCA (B. Amont). Emission routine for VOCs, NOx, and CO. • Liquid phase for 10 soluble species (HNO3, H2O2…) based on Grégoire et al. 1996. Adsorbsion on ice not yet included. • LNOx parameterisation from Pickering et al., 1998 LaMP

  18. • Cloud top Radar observations • Precipitations 3D mesoscale Modelling in the Frame of Hibiscus HIBISCUS from Bauru, Brazil in 2003 and 2004. 2004 with TROCCINOX/ TROCCIBRAS. Pre-HIBISCUS in 2001 Our aim : study the impact of continental convective systems on the chemical composition (UT and TTL) First step: check that the meteorological simulation of the convective system is correct. • Convection on continental region is highly dependent on the soil moisture (more difficult than oceanic cases) • Water vapor (comparison with balloon-borne measurements

  19. 3D mesoscale Modelling in the Frame of Hibiscus Meteorological validation of the meteorological reseults February 14, 2004 (V. Marécal et al., submitted 2006) 1 grid simulation 20 km x 20 km with B-RAMS : organized case Accumulated rainfall rate (15 h) Observations from TRMM B-RAMS Model

  20. 3D mesoscale Modelling in the Frame of Hibiscus Meteorological validation of the meteorological reseults February 8, 2001 (V. Marécal et al., ACP 2006) 2 grid simulation with RAMS : unorganized case Accumulated rainfall rate model Observations Bauru radar More difficult to model

  21. ◊ With LNOx • 42 hour simulations ◊ Without LNOx 3D mesoscale Modelling in the Frame of Hibiscus Chemical results from the February 8, 2001 case (see Marecal et al. 2006 & Rivière et al., 2006, ACP for details) • Very severe unorganized convective case • 2 nested grids, 628 km x 608 km with 4km resolution for the fine grid, 0.5 km vertical resolution in the UTLS

  22. 3D mesoscale Modelling in the Frame of Hibiscus Chemical results from the February 8, 2001 case (see Marecal et al. 2006 & Rivière et al., 2006, ACP for details) Mean NOx no LNOx LNOx Initial Ozone precursors are transported up to 13-15 km

  23. 20 17 14 11 Correct behavior of the model in the TTL Increase of ozone in the TTL related to convection activity 8 3D mesoscale Modelling in the Frame of Hibiscus Ozone time evolution in the fine grid – comparison with DMI sondes mean RAMS O3, fine grid before convection TTL Altitude (km) mean RAMS O3, fine grid after convection mean of DMI ozonesondes from Bauru Range of the DMI-O3 measurments 0.01 0.10 1.00 10.0 Ozone (ppmv)

  24. Convection Mass conservation Wave breaking ? Importance of LNOx 3D mesoscale Modelling in the Frame of Hibiscus Ozone budget in the TTL Dynamics / Chemistry

  25. 3D mesoscale Modelling in the Frame of Hibiscus Wave generated by convection – impact on STE ? Vertical velocity at the tropopause level

  26. Modelling chemistry related to continental tropical deep convection with a mesoscale model is a chalenging task. ◊ Meteorology is difficult to model (dependency on the soil moisture) ◊ Quality of the emission data ◊ Expensive to compute : uncomplete chemistry • 3D mesoscale models with chemistry are powerful tools to study the chemistry of the TTL / continental deep convection ◊ Most of the processes responsible for the TTL composition can be taken into account ◊ Full complexity of convective systems Conclusion

  27. Conclusion #2 • For a severe case during pre-HIBISCUS 2001 importance of dynamics + LNOx in the O3 concentration in the TTL  looking forward to seeing the conclusion of TROCCINOX for the evaluation of parameterizations • Lack of measurements to compare model simulations with More campaigns needed  AMMA / SCOUT-O3  TERESINA 2007 (SCOUT-O3) • On going work for 2 HIBISCUS cases including trapping of HNO3 in ice particles. Waves generated by convection • Developement within RAMS  Catt-BRAMS : ◊Change of chemical solver (longer timestep)  more species and more reactions (in collaboration with S. Freitas and K. Longo, CPTEC) ◊ gas adsorption on ice

  28. THANK YOU

  29. 3D mesoscale Modelling in the Frame of Hibiscus Chemical regime - horizontal cross section at 13 km NOx VOCs 22 UT Maximum of convection VOCs/NOx OH

  30. 3D mesoscale Modelling in the Frame of Hibiscus

  31. Emission data to be used in modeling studies NOx over Brazil EDGAR RETRO 0.5°x0.5° 1°x1°

  32. Courtesy : S. Freitas and K. Longo (CPTEC, Brazil)) • 1D approach to be included in 3D models 8 km ◊ Freitas et al., 2006 for plume rise parameterization (application to pyro-cumulus, ) Use a 1D Cloud Resolving Model embedded in each column of a larger-scale atmospheric-chemistry model. Plume-rise due to the strong buoyancy of the hot gases / aerosols emitted during fires Combined effect of biomass burning and deep convection A brief review modeling tools

  33. To investigate the impact of a particular process on the atmospheric composition, cloud scale studies are carried out. - Example of scavenging and rainout:  1D cloud model to study scavenging of soluble gases (Mari et al., 2000)  2D cloud model to study liquid chemistry/gas uptake on ice /scavenging (Yin et al., ACP, 2001; Yin et al., ACP, 2002) in maritime and continental deep convection.  3D cloud model to study the chemical redistribution of variable soluble species by continental deep convective clouds (Barth et al., JGR 2001) A brief review modeling tools(same for continental & maritime deep convection) 1D approach : dynamics + off-line chemistry (Folkins et al., 1997) Able to retrieve a typical « S-shaped » profile of O3 in tropical UT/LS (including continental regions) using SHADOZ ozone sondes

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