yang zhang, betty k. pun, krish vijayaraghavan, shiang-yuh wu and christian seigneur
DESCRIPTION
Incorporation of the Model of Aerosol Dynamics, Reaction, Ionization and Dissolution (MADRID) into CMAQ. Yang Zhang, Betty K. Pun, Krish Vijayaraghavan, Shiang-Yuh Wu and Christian Seigneur AER, San Ramon, CA CMAQ Workshop, October 2002. - PowerPoint PPT PresentationTRANSCRIPT
Incorporation of the Model of Aerosol Dynamics, Reaction, Ionization and Dissolution (MADRID)
into CMAQ
Yang Zhang, Betty K. Pun, Krish Vijayaraghavan, Shiang-Yuh Wu and Christian Seigneur
AER, San Ramon, CA
CMAQ Workshop, October 2002
MADRIDModel of Aerosol Dynamics, Reaction, Ionization,
and Dissolution
Gas/particle mass transfer
• Hybrid algorithm
• Full equilibrium algorithm
Coagulation not important under polluted conditions
Condensable gases
ExistingParticles
Nucleation
Condensation
Coagulation
Gas-to-Particle Conversion Processes in MADRID
• Nucleation (McMurry and Friedlander,1979)• Thermodynamic equilibrium for inorganic species
– ISORROPIA (SO4=, NO3
-, NH4+, Na+, Cl-, water)
• Equilibrium for organic species– Absorption based on empirical data– Dissolution and absorption from first principles
• Diffusion-limited condensation/volatilization– Hybrid mass transfer from Calpado & Pandis or from
Meng et al.– Moving-center algorithm of Jacobson
Major Differences between MADRID and Original CMAQ Module
CMAQ• Modal size distribution
• NH4+, SO4
=, NO3-, Na+, Cl-
• Coagulation• Nucleation• Full equilibrium approach to
simulate mass transfer• Standard dry deposition• Absorption (irreversible) of 6
SOA using chamber data
MADRID• Sectional representation• Same species • Not treated• New particle formation• Hybrid or full equilibrium
approach• Revised flux approach• Two SOA modules
available
SOA Modules in MADRID
MADRID 1• Modified CBM-IV &
RADM2• 4 anthropogenic SOA
(aromatics)• 34 biogenic SOA
(monoterpenes)• Absorption based on
smog chamber data (Odum et al., 1997; Griffin et al., 1999)
MADRID 2• CACM(1)
– 42 condensable products– hydrophobic surrogate SOA
• 4 anthropogenic, 1 biogenic– hydrophilic surrogate SOA
• 3 anthropogenic, 2 biogenic
• Absorption based on estimated properties
• Dissolution into existing aqueous particles
(1) Caltech atmospheric chemistry mechanism
Meteorology
Sectional Modal
CBM-IV / RADM2 + 19 biogenic
reactions or CACM
Sectional PM module
PM concentrations
Sectional
PM chemicalconcentrationsby size section
PM depositionflux by chemical
Pre-Processors
ChemicalTransportModel
Output
Conversion from modal to sectional
PM concentrations
Gas-phase: CBM-IV + 3 biogenic
reactions
Modal PM module
PM chemicalconcentrations
by mode
Dry Deposition(sectional Vdep)
Dry Deposition(modal Vdep)
Emissions, initial conditions, boundary conditions (modal)
ModalSectional
Modal
Incorporation of MADRID into Models-3
Los Angeles Application
• SCAQS episode of 27-28 August 1987
• Simulation using MM5 and CMAQ-MADRID 1
SCAQS 1987 Episode
• 25-29 August 1987• Domain: 63 x 28 grid cells, consistent with previous
modeling exercises• Grid Resolution: 5 km• MM5 used to generate input meteorology• Emission inventory developed from previous
simulations
H AW T
C ELAR IVR
Ventura Los Angeles S an B ernard ino
R ivers ide
S an D iego
Orange
SCAQS Modeling Domain
HAWT
CELARIVR
Model Performance Ozone and PM2.5
Species Error Bias
O3 34% 9%
PM2.5 44% 14%
Model Performance PM2.5 Components
Species Error Bias
Sulfate 38% 11%
Nitrate 45% -38%
EC 54% -20%
OC 49% -22%
Observed and Simulated PM2.5 Composition
27 August 28 August
Sulfate
Nitrate
Ammonium
EC
OC
Others
Observations
MADRID 1
11%
42%
17%
2%
8%
20% 13%
37%
16%
2%
9%
23%
10%
42%
13%
4%
16%
15%9%
42%
13%
4%
15%
17%
Nashville, Tennessee Application
• SOS episode of 15-18 July 1995
• Simulation using MM5 and CMAQ-MADRID 2
Model Performance Ozone, PM2.5 and Sulfate
Species Error Bias
O3 17% 4%
PM2.5 17% -15%
Sulfate 13% -11%
Formation of Condensable Organics
0
2
4
6
8
10
12
14
16
18
20
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68
Time (hr)
Gases
Particles
Condensable products in Nashville
Time (hour)
Con
cent
rati
ons
(g/
m3 )
Formation of Particulate Organics
AEC
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68
SO
A (
g/m
3 )
Biogenic
Anthropogenic
Nashville
Time (hour)
SO
A (g
/m3 )
Hydrophobic vs. Hydrophilic Organics
NAS
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68
SO
A (
g/m
3 )
Hydrophilic SOA
Hydrophobic SOA
Nashville
Time (hour)
SO
A (g
/m3 )
0
2
4
6
8
10
12
14
0 24 48 72
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Sensitivity of Hydrophilic Organics to Henry’s Law Constant
Nashville
Time (hour)
Hyd
roph
ilic
SO
A (g
/m3 )
RH
Base case; H = 1.6 x 106 M/atm Sensitivity case; H = 109 M/atm
RH
Other Applications of MADRID
• Nashville– comparison of three SOA modules
• BRAVO– regional simulation with RADM2 and MADRID 1
• Southeast– applications of MADRID 1 and MADRID 2
• Eastern United States– application of MADRID 1 for one year for nitrogen
deposition
Lessons from PM Simulations
• Accurate PM emission inventories are critical • Secondary organic aerosols remain a major source of
uncertainty• Boundary conditions can have significant effects on
O3 and PM predictions
• Effects of clouds on sulfate need to be simulated for regional haze
• Models yet to be tested for wintertime conditions
Acknowledgments
• Funding for this work was provided by EPRI and CARB
• We would like to thank – J.H. Seinfeld, S. Pandis, M. Jacobson, R. Griffin,
and A. Nenes for providing source codes used in MADRID
– S. Leduc and F. Binkowski for discussions regarding CMAQ