modeling bc sources and sinks - research plan charles q. jia and sunling gong university of toronto...
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Modeling BC Sources and Sinks- research plan
Charles Q. Jia and Sunling GongUniversity of Toronto and Environment Canada
@ 1st annual NETCARE workshop
Outline Objective and approach GEM-MACH Canadian Aerosol Module (CAM) An example: Arctic BC seasonal
variation
Objective and Approach 1. To enhance the capacity of GEM-MACH in
forecasting BC in the Arctic • incorporating the science from NETCARE to better
represent BC processes in the CAM (e.g. BC aging)• using the measurement data from NETCARE to
validate the model2. To better understand the sources and sinks of BC in
the Arctic region• using the enhanced GEM-MACH • focusing on relative contributions of various
sources (e.g. natural vs. anthropogenic) and long-range transport
• GEM: Global Environmental Multi-scale Model– An operational numerical weather forecasting model– Developed by Meteorological Service of Canada (MSC)
[Cote et al., 1998; Yeh et al., 2002]. • MACH: Two air quality modules (ADOM and CAM)
– The Acid Deposition and Oxidants Model (ADOM) is an integrated gas-phase chemistry module [Venkatram et al., 1988].
– The Canadian Aerosol Module (CAM) simulates physical and chemical processes of size-resolved aerosol in the atmosphere [Gong et al., 2003]
GEM-MACH Global Environmental Multiscale
Modeling Air Quality and CHemistry
GEM-MACH Structure
SMOKERegional DataCanada & US
SMOKERegional DataCanada & US
Gas PhaseChemistry
Gas PhaseChemistry
CAMCanadian Aerosol Module
CAMCanadian Aerosol Module
GEM
Met
eoro
logy
Tra
nspo
rt
Emis
sion
Inte
rfac
eEm
issi
on In
terf
ace
Chem
istr
y In
terf
ace
Chem
istr
y In
terf
ace
Global Emissions
Global Emissions
Canadian Aerosol Module (CAM)
• Simulates physical and chemical processes of aerosols in the atmosphere [Gong et al., 2003]• Emissions, in-cloud and below-cloud scavenging, dry
deposition, coagulation, condensation, nucleation et al.
• Size-resolved: 12 particle size bins (0.01 to 41 μm in diameter)
• Multi-component: 5 species (BC, OC, sulphate, sea salt, soil dust)
An example: importance of depositional processes in
seasonal variation of the Arctic BC
(Huang L. et al., JGR, V115, D17207, 2010)
Seasonal Variation of the Arctic BCModel Simulation vs. Observation
(surface BC)
8
BC
(pp
tm)
Obs. (Sharma et al., 2006)
11-model predictions
[Shindell et al., 2008]
Barrow
ZeppelinAlert
Red- IMPROVE site at Barrow (1996-1998)
9
Enhanced In-cloud Scavenging Parameterization
)1( tcloudin
cloudin
et
F
Cdt
dC
Original (empirical)
[Giorgi and Chameides, 1986]
Enhanced
F – GEM cloud cover
P – GEM precipitation
air
P
z L
0
0
(cloud cover)QF
FQ L
0
0 0
(rate of precip. formation)Q
F F L
Effects of Enhanced Parameterization of In-cloud Scavenging
10
Correlation Coefficient, R
before after
Alert 0.49 0.91
Barrow -0.51 0.58
Zeppelin -0.13 0.77
Feb Apr Jun Aug Oct Dec
0
30
60
90
120
Observed Original In-cloud scavenging Enhanced In-cloud scavenging
BC
(ng/
m3)
(a) Alert (2001)
Feb Apr Jun Aug Oct Dec
0
10
20
30
40
50
60
BC
(ng/
m3)
(b) Barrow (2001)
Feb Apr Jun Aug Oct Dec
0
30
60
90
BC
(ng/
m3)
(c) Zeppelin (2001)
Observations at Zeppelin: Eleftheriadis et al., 2009
11
Enhanced below-cloud scavenging parameterization
)(,360010 3
tp
cloudbelow
cloudbelow
ufED
pE
Cdt
dC
Original
Valid when Re < 0.1
Enhanced
, (any Re)
Re – [Feng, 2007]
pa
at du
Re
a
papt
gdu
18
)( 2
12
Effects of Enhanced Parameterization of Below-cloud Scavenging
Correlation Coefficient, R
beforeafter
Alert 0.91 0.95
Barrow 0.58 0.50
Zeppelin 0.77 0.81
Feb Apr Jun Aug Oct Dec
0
30
60
90
120
Observed Original below-cloud scavenging Enhanced below-cloud scavenging
BC
(ng/
m3)
(a) Alert (2001)
Feb Apr Jun Aug Oct Dec
0
10
20
30
40
50
60
BC
(ng/
m3)
(b) Barrow (2001)
Feb Apr Jun Aug Oct Dec
0
30
60
90
BC
(ng/
m3)
(c) Zeppelin (2001)
Thanks!