Présentation PowerPointEmmanuel 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
Modeling deep convection and chemistry in the continental tropics
3.unknown
+What is specific to continental deep convection ?
(with respect to oceanic deep convection)
Review :
3D mesoscale Modelling in the Frame of Hibiscus
Conclusion
Outline
Introduction
What drives the composition of the upper troposphere and the TTL when deep convection occurs ?
UTLS
TTL
stratosphere
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
Homogeneous chemistry
LNOx
Emissions
STE
(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 ?)
TTL modeling workshop, Victoria
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TTL modeling workshop, Victoria
Introduction
Modeling the chemical composition of the continental tropics need to account for all these processes.
Homogeneous chemistry
LNOx
Emissions
STE
TTL modeling workshop, Victoria
• 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 :
EDGAR
TTL modeling workshop, Victoria
Cloud scale simulations with RAMS-chemistry
50 km x 50 km grid 1km x 1km resolution 3h simulation
Emission from EDGAR :
times less)
+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) :
3D mesoscale Modelling in the Frame of Hibiscus
Conclusion
A brief review (not exhaustive)
HIBISCUS/TROCCINOX/TROCCIBRAS – TROCCINOX 2
TRACE-A, (mostly oceanic, continental in Southern Africa)
Balloon and aircraft plateforms. O3, H2O, CH4, NO2, BrO, NOx and NOy
CO2
Measurements onboard commercial aircraft
O3 and H2O MOZAIC over Brazil up to 10-12 km (FranckfurtSao Paulo)
ABLE-2 Central Brazil dry and wet season : O3, CO, NO, PAN.
TROPOZ South America, O3, NO, CO.
aircrafts
A brief review #2
Lack of data over the continental tropics especially during the wet season
Emmons et al., JGR, 2000.
O3 airborne measurements
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
A brief review #3
Aircrafts and balloons : O3, H2O, CH4, NOx, NOy, VOC.
Summer 2006.
A brief review
Large numbers of modeling approach 1D, 2D, 3D… : choice depends on the process to study
Computing efficiency is increasing full regional scale studies dynamics/microphysics/chemistry are now possible. New point of view
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
TTL modeling workshop, Victoria
3D modelling with chemistry : regional and global scale
Labrador et al GRL (2004) : impact of LNOx at 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 + …
TTL modeling workshop, Victoria
+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) :
3D mesoscale Modelling in the Frame of Hibiscus
Conclusion
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
3D mesoscale Modelling in the Frame of Hibiscus
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
HIBISCUS from Bauru, Brazil in 2003 and 2004. 2004 with TROCCINOX/ TROCCIBRAS. Pre-HIBISCUS in 2001
• Cloud top
Meteorological validation of the meteorological reseults
Observations from TRMM
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)
TTL modeling workshop, Victoria
February 8, 2001 (V. Marécal et al., ACP 2006)
2 grid simulation with RAMS : unorganized case
Accumulated rainfall rate
More difficult to model
TTL modeling workshop, Victoria
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
• 42 hour simulations
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)
LNOx
Mean NOx
3D mesoscale Modelling in the Frame of Hibiscus
Ozone time evolution in the fine grid – comparison with DMI sondes
mean of DMI ozonesondes from Bauru
mean RAMS O3, fine grid
after convection
before convection
0.01 0.10 1.00 10.0
Increase of ozone in the TTL related to convection activity
TTL modeling workshop, Victoria
Ozone budget in the TTL Dynamics / Chemistry
In 1030 molec O3
Wave generated by convection – impact on STE ?
Vertical velocity at the tropopause level
TTL modeling workshop, Victoria
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
◊ Full complexity of convective systems
◊ Most of the processes responsible for the TTL composition can be taken into account
TTL modeling workshop, Victoria
More campaigns needed
AMMA / SCOUT-O3 TERESINA 2007 (SCOUT-O3)
◊ Change of chemical solver (longer timestep) more species and more reactions (in collaboration with S. Freitas and K. Longo, CPTEC)
◊ gas adsorption on ice
On going work for 2 HIBISCUS cases including trapping of HNO3 in ice particles. Waves generated by convection
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
TTL modeling workshop, Victoria
NOx
VOCs
VOCs/NOx
OH
TTL modeling workshop, Victoria
EDGAR
RETRO
◊ Freitas et al., 2006 for plume rise parameterization (application to pyro-cumulus, )
8 km
Plume-rise due to the strong buoyancy of the hot gases / aerosols emitted during fires
Use a 1D Cloud Resolving Model embedded in each column of a larger-scale atmospheric-chemistry model.
Combined effect of biomass burning and deep convection
TTL modeling workshop, Victoria
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
A brief review
To investigate the impact of a particular process on the atmospheric composition, cloud scale studies are carried out.
- Example of scavenging and rainout:
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)