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CHIMERE WORKSHOP - 21-22 March 2005
THE AEROSOLS IN CHIMERE
Bertrand Bessagnet
Main scientific collaborations IPSL
(Institut Pierre Simon Laplace) LISA
(Laboratoire Inter-universitaire des Système
Atmosphérique) LA (Laboratoire dAérologie)
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The aerosol module
Q µg/m3
Sectional representation 6 bins (10nm - 40µm)
can be
changed by the user
PM 2.5
PM 10
0.01
0.04
40
10
2.5
0.62
0.16
D µm
Particle composition 8-9 species

• PPM (Primary Particulate Matter)
• DUST (desert dusts and local erosion)
• NH4 (Ammonium)

Primary

• SO4 (Sulfate)
• NO3 (Nitrate)
• ASOA (Anthropogenic Secondary Organic Aerosols)
• BSOA (Biogenic Secondary Organic Aerosols)

Secondary
SOA

• Water

• Sea salts (from Monahan, 1986)

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PPM emissions
PPM2 2.5 µm lt ? lt 10 µm PPM3 ? lt 2.5 µm
PPM1 ? gt 10 µm
TNO emissions 0.25x0.25 (1995)
EMEP webdab emissions 0.5x0.5
CHIMERE
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Sulfate chemistry
- Oxidation in the gas phase (OH) - Oxidation
in the aqueous phase with O3, H2O2, NO2 - Very
ph sensitive ( ph  estimated  by solving the
electron balance equation 4ltphlt6,
off line at each time step) - Reactions with
Iron and Manganese
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Aqueous sulfate chemistry
- Main difficulty evaporation/condensation
cycle of water droplets
Henry s law
Cloud droplets
Sulfate
Evaporation

pH5
10 µm
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Heterogeneous chemistry
Main sources Jacob, 2000 Aumont et al, 2003
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Other processes

• Multicomponent coagulation (Gelbard and Seinfeld,
  1980)
• Dry deposition (Pandis and Seinfeld, 1998)
• Kulmala s parameterization (1998)
• Thermodynamic equilibrium (ISORROPIA or a table)
• Absorption process for semi-volatile species

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Particle wet scavenging
Sub cloud
In cloud
10µm
1mm
? empirical uptake coefficient Pr
precipitation rate released Wl liquid water
content h grid cell height
a empirical coefficient P precipitation
rate E collision efficiency coefficient Ug
particle velocity
Particule
Goutte deau
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The missing mass...
Annual mean of predicted and observed PM10 (µg/m3)
Mod.
Obs.
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The missing mass...

• - Resuspension of deposited particles
• - Resuspension of debris (biogenic and
  anthropenic)
• Local erosion
• - Boundary conditions (generally  zero  in the
  models)

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Boundary conditions
From the GOCART Model (Mian Chin, NASA) monthly
data (2000-2001)
GOCART species CHIMERE species

• BC
• OC
• Dust (desert)
• SO4
• Sea salts

• PPM
• ASOA
• BSOA
• Dust
• SO4
• Sea salts

Interface (spatial interpolation) preptop_GOCART.f
preplat_GOCART.f
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Boundary conditionsGOCART data
Sulfate hydrophobic BC hydrophobic OC hydrophilic
BC hydrophilic OC DUST Sea salts .
No size segregation
0.1 0.18 0.30 0.60 1.00
1.80 3.00 6.00 10.0 radius (µ)
0.1 0.5 1.50 5.00 10.0
radius (µ)
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Boundary conditions
Special treatment for dust A coefficient is
applied to dust GOCART data 0.25-0.30
Representative of background values
Miami
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Boundary conditionsImpact of dusts
Without dust
With dust
PM10 mean concentrations (µg/m3) in a summer case
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Boundary conditionsImpact of dust
Zarra (Spain)
with boundary dust
dot observations grey line simulation without
dust black line simulation with dust
without boundary dust
Triangle rural north Circle rural
south Square urban north Diamond urban south
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SOA chemistry
Very primitive up to now !! various sources for
the yields, and partitioning coefficients
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Next developments - SOA moduleAvailable in fall
!!

• Xylene
• Toluene
• A-Pinene
• B-Pinene
• Sabinene
• Limonene
• Terpinene
• Ocimene
• Humulene

Chemical scheme

• 9 SOA products
• 4 SOA products

Collaboration with Seigneur C., Pun B., AER
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PM episode - March 2004
Gennevilliers (near Paris)
PM10 concentrations µg/m3
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PM episode - March 2004
PM10 in µg/m3
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PM episode - March 2004
Nitrate in µg/m3