TTL modeling workshop, Victoria Emmanuel Rivière (1), V. Marécal (2), and contribution from the HIBISCUS/TROCCIBRAS participants 1 GSMA/ CNRS and Université

TTL modeling workshop, Victoria

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

Modeling deep convection and chemistry in the continental tropics


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

OutlineOutline


IntroductionIntroduction

What drives the composition of the upper troposphere and the TTL when deep convection occurs ?

UTLSTTL

stratosphere

Boundary layer

free troposphere

TropicsMid-latitudes

tropopause

deep convection

11 km

17 km

0 km

Homogeneous chemistry

LNOx

emissions

Emissions

STE

slow ascent

waves

Additional O3 production

O3

Aqueous / ice chemistry(+ scavenging)

scavenging

Vertical transport

« overshoot »

LNOx



Modeling the chemical composition of the continental tropics need to account for all these processes.


Vertical transport by deep convection

LNOx

Emissions

STE


These processes occur both over the oceans and the continents


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 ?)


Liu and Zipser, JGR, 2005 from TRMM observations

Higher convection over continents. Overshoots mainly above continents.

‰

Overshoot occurrence

What is specific to continental deep convection ? (with respect to maritime deep convection) #2



Modeling the chemical composition of the continental tropics need to account for all these processes.



Vertical transport by deep convection

LNOx

Emissions

STE

VOCs, NOx, CO…

Higher

Overshoots more likely

Enhanced production because of a more severe convection


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

Emission data to be used in modeling studies


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)


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


Conclusion


Field Campaigns in the continental Tropics

A brief review (not exhaustive)A brief review (not exhaustive)

HIBISCUS/TROCCINOX/TROCCIBRAS – TROCCINOX 2

SHADOZ (O3 sondes in the tropics, continental sometimes)

TRACE-A, (mostly oceanic, continental in Southern Africa)

Balloon and aircraft plateforms. O3, H2O, CH4, NO2, BrO, NOx and NOy

CO2

Measurements onboard commercial aircraftO3 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.airc

rafts

Bal

loon

s, s

onde

s


Fields Campaign in the continental Tropics

A brief review #2A brief review #2

Lack of data over the continental tropics especially during the wet season

Emmons et al., JGR, 2000.

O3 airborne measurements

6-8 km


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 #3A brief review #3

AMMA West Africa during the monsoon + SCOUT-O3

Aircrafts and balloons : O3, H2O, CH4, NOx, NOy, VOC.

Summer 2006.


modeling tools

A brief reviewA 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


modeling tools


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 + …


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


Conclusion


3D mesoscale Modelling in the Frame of Hibiscus3D 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

LaM

P



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)

• Cloud top

• PrecipitationsRadar observations

• Water vapor (comparison with balloon-borne measurements

HIBISCUS from Bauru, Brazil in 2003 and 2004. 2004 with TROCCINOX/ TROCCIBRAS. Pre-HIBISCUS in 2001



Meteorological validation of the meteorological reseults

Observations from TRMM B-RAMS Model

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 Bauru radar

model

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


More difficult to model



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

• 42 hour simulations ◊ With LNOx

◊ Without LNOx

• 2 nested grids, 628 km x 608 km with 4km resolution for the fine grid, 0.5 km vertical resolution in the UTLS



Chemical results from the February 8, 2001 case

(see Marecal et al. 2006 & Rivière et al., 2006, ACP for details)

LNOx

no LNOx

InitialOzone precursors are transported up to 13-15 km

Mean NOx



Ozone time evolution in the fine grid – comparison with DMI sondes

mean of DMI ozonesondes from Bauru

mean RAMS O3, fine gridafter convection

mean RAMS O3, fine gridbefore convection

Range of the DMI-O3 measurments

0.01 0.10 1.00 10.0 Ozone (ppmv)

8

11

14

17

20

Alti

tude

(km

)

Correct behavior of the model in the TTLIncrease of ozone in the TTL related to convection activity

TTL



Ozone budget in the TTL Dynamics / Chemistry

In 1030 molec O3 total

Top (17 km )

Bottom (13 km)

Horizontal Chemistry

24 hperiod

97.5 23.3 68.7 -23.1 28.7

ConvectivePeriod (8 h)

11.0 34.2 52.2 -91.8 16.4

Wave breaking ? Importance of LNOx

Convection

Mass conservation



Wave generated by convection – impact on STE ?

Vertical velocity at the tropopause level


ConclusionConclusion

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


Conclusion #2Conclusion #2

Developement within RAMS Catt-BRAMS :

Lack of measurements to compare model simulations withMore 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


THANK YOU



Chemical regime - horizontal cross section at 13 km

NOx VOCs

VOCs/NOx OH22 UTMaximum of convection




Emission data to be used in modeling studies

EDGAR RETRO

1°x1° 0.5°x0.5°

NOx over Brazil


modeling tools


1D approach to be included in 3D models

Courtesy : S. Freitas and K. Longo (CPTEC, Brazil))

◊ Freitas et al., 2006 for plume rise parameterization (application to pyro-cumulus, )

8 km

Plume-rise due to the Plume-rise due to the strong buoyancy of the hot strong buoyancy of the hot gases / aerosols emitted gases / aerosols emitted during firesduring 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


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

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)

1D cloud model to study scavenging of soluble gases (Mari et al., 2000)


Documents

TTL modeling workshop, Victoria Emmanuel Rivière (1), V. Marécal (2), and contribution from the HIBISCUS/TROCCIBRAS participants 1 GSMA/ CNRS and Université