Upload
diata
View
29
Download
0
Embed Size (px)
DESCRIPTION
Robin L. Dennis Atmospheric Sciences Modeling Division Air Resources Laboratory, NOAA/US EPA Research Triangle Park, NC 27711 European Monitoring and Evaluation Program (EMEP) Workshop on Particulate Matter Measurement and Modeling April 20-23, 2004 New Orleans, Louisiana, USA. - PowerPoint PPT Presentation
Citation preview
Robin L. Dennis
Atmospheric Sciences Modeling DivisionAir Resources Laboratory, NOAA/US EPA
Research Triangle Park, NC 27711
European Monitoring and Evaluation Program (EMEP)Workshop on Particulate Matter Measurement and Modeling
April 20-23, 2004New Orleans, Louisiana, USA
Evaluation of 3-D RegionalParticulate Models:
Measurement Needs for Inorganic Species
Acknowledgements
Shawn Roselle and Shaocai Yu provided valuable assistance in making the CMAQ runs and conducting analyses.
Preliminary Supersite data were provided by Spyros Pandis (Pittsburgh) and Jay Turner (St. Louis). Data were provided
by the SEARCH and the Atlanta Supersite Programs.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency
policy.
Robin Dennis is on assignment to the National Exposure Research Laboratory, U.S. Environmental Protection Agency
Policy Issues for the Inorganic System*
• Are we getting the right mix of inorganic fine particles
• What degree of nitrate replacement for sulfate will there be
• Which is more effective: NOX control or NH3 control– What are other consequences (e.g., acidity, O3, SO4
2-, SOA)– What happens to character as well as mass
• What is degree of acidity of aerosols in general and sulfate
• What is the effectiveness of urban-oriented controls
• New insights from special measurement campaigns
* Courtesy of John Bachmann, EPA
PRIMARY EMISSIONS
VOC
CO NOSO2
NH3
NO2
HNO3 H2SO4
O3
Gas Phase
Fine Particles
hv
OH
O3
OH
OHHO2RO2
NO3
PMfine
SO4
PMfine
H2O2O3Fe
O3NO3
N2O5
H2OHeterogeneous
Evaluation Thrusts(Focus of the testing and the talk)
• System Setup• Budgets
• Gas/Particle Partitioning• Current state of the gas/aerosol system
• Response Dynamics• Move to future states of the gas/aerosol system
Log10 Annual Area Source Ammonia Emissions
Summer: August 1999 Winter: January 2002 CMAQ @ 32-km resolution CMAQ @ 36-km resolution
3 Sites:
Pittsburgh, PA
St. Louis, MO
Atlanta, GA
System Setup(budgets)
• SOX emissions• Sulfate production and losses• NOX emissions
• Total-Nitrate (HNO3+aNO3-) production and losses
• Day (gas) versus nighttime (heterogeneous) pathway differences
• NHX (NH3+NH4+) emissions and losses
• Getting NHX right is important (dilemma: official or best for model?)» Seasonal» Daily» Diurnal
• Meteorological inputs• Boundary layer height (sensible/latent heat); vertical mixing rates
Jefferson Street Jan02 (9 Day) CMAQ Comparisons
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 4 8 12 16 20 24
Hour (EST)
HNO
3 Av
erag
e (p
pb)
02Release NewHeteroRxn NoHeteroRxn JSTHNO3
Yorkville Jan02 (9 Day) CMAQ Comparisons
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
0 4 8 12 16 20 24
Hour (EST)
HNO
3 Av
erag
e (p
pb)
02Release NewHeteroRxn NoHeteroRxn YRKHNO3
•HNO3 concentrations significantly reduced with updated CMAQ•Must turn off all production from N2O5 to get down to observed levels of HNO3•Daytime over-production of HNO3 is also an issue (winter photochemistry)•These are more winter than summer issues
Atlanta: HNO3 (average diurnal cycle)
Urban Suburban
•Inverse modeling against monthly NH4 wet concentrations was used to define seasonality of NH3 emissions
•Having the correct NH3 seasonality was critical to getting surface NHx right
Jefferson St Aug99 NHx Comparison
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
8/13 8/16 8/19 8/22 8/25 8/28 8/31
Day (EST, 8/13-8/31 1999)
Tota
l NHX
(ug/
m3 )
JeffStNHx 02Model 03ModelNHx
The CMAQ NHX predictions track the synoptic signal quitewell, but they do not track the measured diurnal pattern
Atlanta: NHX
Jefferson Street Aug99 ANO3 Diurnal Average Comparison
0
1
2
3
4
5
6
7
8
9
0 4 8 12 16 20 24
Hour (EST)ANO3 (u
g/m
3)
JSTANO3 02ModelANO3 H3uModelNO3
Diurnal biases in NHX show up as biases in aerosol nitrate,especially in the early morning.
Atlanta: NO3-
Jefferson St Aug99 Diurnal Ave NHx Comparison
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
0 4 8 12 16 20 24
Hour (EST) [Period = 8/15-8/31]
Tota
l NH
X (u
g/m
3)
JST-StNHx 02Mod-StNHx 03Mod-StNHx
Atlanta: NHX
Aug99 (Month) CMAQ Jefferson St Compare
0102030405060708090
100
0 4 8 12 16 20 24
Hour (EST)
NOy
(ppb
)
JSTNOy 02ModelNOy 03Mod4.3NOy
Aug99 (Month) CMAQ Centerville Compare
0123456789
0 4 8 12 16 20 24
Hour (EST)
NO
y (p
pb)
CTRNOy
ModelNOy
Rural NOY
Urban NOY
We see a pattern of early evening overprediction at urban and rural Sites. We believe the PBL is collapsing pre-maturely.
Measurements to Support EvaluationSystem Setup
• Inert/slowly reacting “primary” specie (check meteorology) EC will do; also NOY and CO
• Temperature (soil moisture)• SO4
2-
• NOY, HNO3 (O3, NOX [= NO + true-NO2] to examine O3 production)• Total-Nitrate (total because looking at budgets)• NHX (total because looking at budgets)• Wet deposition, rainfall amounts (dry deposition)
Gas/Particle Partitioning(Current conditions)
• Equilibrium dynamics• Model errors affecting the partitioning
» Temperature• Measurement errors affecting the testing of equilibrium module
• Other conditions than assumed in the model• Non-equilibrium dynamics• External instead of internal mixture• Non-equilibrium pathways
• Coarse particle interactions• Loss pathways
-2
0
2
4
6
8
10
-10 -5 0 5 10 15 20 25
Data 5TemperatureRobinNO3 (observed Temperature)NO3 (MM5 Temperature)
NO
3- (
g m
-3)
Observed Temperature
Fig. Difference in predictions of aerosol NO3
- with observed and modeled (MM5) temperatures at the Pittsburgh site
0
2
4
6
8
10
0 2 4 6 8 10
NO
3- (MM
5 T)
NO3
- (observed T)
-10
-5
0
5
10
15
20
25
-10 -5 0 5 10 15 20 25
MM
5 T
(C)
observed T (C)Time (EST, 2002)
-10-505
10152025
1/2 1/6 1/10 1/14 1/18 1/22 1/26 1/30
Observed TemperatureMM5 Temperature
Tem
pera
ture
(C)
0
2
4
6
8
10
1/2 1/6 1/10 1/14 1/18 1/22 1/26 1/30
NO3 (observed Temperature)NO3 (MM5 Temperature)
NO
3- (
g m
-3)
Differences in predictions of NO3- with observed and modeled (MM5)
temperatures at the Pittsburgh site in January 2002. Differences aregreatest at the higher temperatures.
Base-case aerosol NO3
- ( g m-3)
Sen
sivi
tity-
case
aer
osol
NO
3- ( g
m-3
)
10-3
10-2
10-1
100
101
Errors in SO4
2- and TNH4
10-3
10-2
10-1
100
101
Errors in SO4
2-
10-3
10-2
10-1
100
101
10-3 10-2 10-1 100 101
Errors in TNH4
Base-case aerosol NO3
- ( g m-3)
Sen
sivi
tity-
case
aer
osol
NO
3- ( g
m-3
)
10-3
10-2
10-1
100
101
Errors in SO4
2- and TNH4
10-3
10-2
10-1
100
101
Errors in SO4
2-
10-3
10-2
10-1
100
101
10-3 10-2 10-1 100 101
Errors in TNH4
Base-case aerosol NO3
- ( g m-3)
Sen
sivi
tity-
case
aer
osol
NO
3- ( g
m-3
)
10-3
10-2
10-1
100
101
Errors in SO4
2- and TNH4
10-3
10-2
10-1
100
101
Errors in SO4
2-
10-3
10-2
10-1
100
101
10-3 10-2 10-1 100 101
Errors in TNH4
Ran
dom
err
or s
ensi
tivity
aer
osol
NO
3- (ug
/m3 )
Base case aerosol NO3- (ug/m3)
•Gaussian random error (1σ=15% to mimic measurement error) superimposedon inputs of SO4
2- and NHX causes a large uncertainty in the prediction of NO3-.
•The error in NHX has a larger impact than the error in SO42-.
7/25 7/260
2
4
6
8
Aer
osol
Nitr
ate
(g
/m3 )
DateDate
Aer
osol
Nitr
ate
(g
/m3 )
observed range median of predicted
1/20 1/21 1/2202468
10
1/15 1/16 1/170
2
4
6
8
observed range median of predicted
Figure 3. Results from Monte Carlo simulations performed for selected periods in July 2001 and January 2002. Error bars extend to the 5th and 95th percentiles of the cumulative distribution function associated with each prediction. The shaded area bounds the interval between the 5th and 95th percentiles of the observed aerosol nitrate cumulative distribution functions, although concentrations below zero are not shown. (courtesy Spyros Pandis)
11 14 17 200
1
2
3
11 14 17 20
observed predicted
July 9 July 21
internally mixed liquid
11 14 17 200
1
2
3
Aer
osol
Nitr
ate
(g/
m3 )
Hour11 14 17 20
externally mixed liquid + solid
Figure 5. Simulations for July 9 and 21 assuming that particles are 1) internally mixed liquid aerosols, and 2) an external mixture of crystallized ammonium sulfate and wet acidic
aerosols when the relative humidity is below 40%. (courtesy Spyros Pandis)
Jefferson Street Aug99 ANO3 Diurnal Average Comparison
0
1
2
3
4
5
6
7
8
9
0 4 8 12 16 20 24
Hour (EST)
AN
O3
(ug/
m3)
JSTANO3 02ModelANO3 H3uModelNO3
August ’99 Atlanta: NO3-
While there appears to be a daytime under-prediction of NO3- by the model,
single-particle mass spec measurements (Lee, Murphy, et al.) show the nitratewas not associated with ammonium (i.e., not the standard equilibrium pathway).
Measurements to Support EvaluationGas/Particle Partitioning
• SO42-
• HNO3 and NO3-
• NH3 and NH4+
• Base cations (coarse and fine)• Single particle mass spectrometer particle composition
information• Coarse particles (chemical composition by size)• T, RH• Good characterization of measurement error; best
accuracy and precision possible (10%)
Response Dynamics
• Gas Ratio (Excess Ammonia), modified Gas Ratio• Hourly• Daily
• Degree of neutralization
• Gas/Particle fractions
Gas Ratio(per S. Pandis)
Free Ammonia NHX - 2 * SO42-
GR = ---------------------- = ------------------------------
Total Nitrate HNO3(g) + NO3-(p)
Calculated in Molar Units
GR > 1 => HNO3 limiting
0 < GR < 1 => NH3 limiting
GR < 0 => NH3 severely limiting (can’t form NH4NO3)
Gas Ratio for Pittsburgh: Winter 2002
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
1/4/
2002
0:0
0
1/7/
2002
0:0
0
1/10
/200
2 0:
00
1/13
/200
2 0:
00
1/16
/200
2 0:
00
1/19
/200
2 0:
00
1/22
/200
2 0:
00
1/25
/200
2 0:
00
1/28
/200
2 0:
00
1/31
/200
2 0:
00
Day : Start-Hour
Gas
Rat
io
SchPk Gas Ratio H3uModGasRatio
The modeled and observed Gas Ratios are reasonably consistent. The majorexcursions are mostly associated with plume(1) and wet deposition events(3).
Gas Ratio for Pittsburgh: Winter 2002
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
1/4/
2002
0:0
0
1/7/
2002
0:0
0
1/10
/200
2 0:
00
1/13
/200
2 0:
00
1/16
/200
2 0:
00
1/19
/200
2 0:
00
1/22
/200
2 0:
00
1/25
/200
2 0:
00
1/28
/200
2 0:
00
1/31
/200
2 0:
00Day : Start-Hour
Gas
Rat
io
SchPk Gas Ratio H3uModGasRatio
Daily Gas Ratio Compare: Pittsburgh Winter 2002
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
1/2/20
02
1/6/20
02
1/10
/200
2
1/14
/200
2
1/18
/200
2
1/22
/200
2
1/26
/200
2
1/30
/200
2
Day : Start-Hour
Gas
Ratio
SchPark-SS Gas Ratio 03Release
A fair amount of the hourly Gas Ratio comparison information is able to becaptured by daily Gas Ratio comparisons, although interpretation is mostinsightful and reliable at the hourly time resolution.
St Louis Jan 2002 CMAQ Gas Ratio Comparison
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
12/31/2001 1/5/2002 1/10/2002 1/15/2002 1/20/2002 1/25/2002 1/30/2002
Day
Dai
ly G
as R
atio
H3uModel Gas Ratio NoN2O5Model Gas Ratio StL-SSObs Gas Ratio
Daily Gas Ratio Compare: Pittsburgh Winter 2002
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
1/2/20
02
1/6/20
02
1/10
/200
2
1/14
/200
2
1/18
/200
2
1/22
/200
2
1/26
/200
2
1/30
/200
2
Day : Start-Hour
Gas
Ratio
SchPark-SS Gas Ratio 03Release
Gas Ratio comparisons can vary considerable across space due to differencesin model biases. At Pittsburgh Total-Nitrate and NHX are both biased high. AtSt. Louis Total-Nitrate is high and NHX is biased low.
• SO42-
• Minimally Total-Nitrate, but prefer HNO3 and NO3-
• Minimally NHX, but prefer NH3 and NH4+
• Temperature (for interpretation)• Precipitation (for interpretation)• Wet deposition (for interpretation)
Measurements to Support EvaluationResponse Dynamics
Summary of Evaluation Measurement Needs• Critical Suite (continuous)
• SO2 and SO42-
• HNO3 and NO3- (Total-Nitrate as 2nd choice)
• NH3 and NH4+ (NHX as 2nd choice)
• Base cations (coarse and fine) and other anions (e.g., Cl and Br)• Inert/slowly reacting “primary” specie (check meteorology)
» EC will do; also NOY and CO• T, RH, Precipitation, WD• Wet deposition (Daily; Weekly as 2nd choice)
• Additions for a Full Set (continuous)• NOY, HNO3, O3, NOX (=NO+true-NO2), H2O2, PAN (Ox. capacity; O3 prod’n)• Coarse particles (chemical composition by size)• Single particle mass spectrometer particle composition data• Good characterization of measurement error; best accuracy and
precision possible (goal: 10%)• Dry deposition flux (direct as possible) of gases and particles• Satellite sites for sub-grid variability studies
• Hourly vs. Daily perspective (need continuous)• Now: Several continuous, Many/most daily sites with critical suite• Future: Most sites with critical suite of continuous measurements
• Summer vs. Winter perspective• Winter needs to get equal experiment time for special intensives
» Eventually the entire year needs to be covered
• Regional/Rural vs. Local/Urban• Harmonize techniques. If separate networks, then need to have careful
intercomparisons» Degree of comparability needs to be established
• Wet and Dry Deposition perspective• Wet: collocation; daily most useful but pragmatism may say longer• Dry: issue of carrying out special measurement programs - particles
• Subgrid Variability• Attacked through select measurement clusters (annual)
» Variability of budgets (setup), species partitioning, Gas Ratio
Summary of Eval. Measurement Needs (cont.)
Extra Slides
PRIMARY EMISSIONS
VOC
CO NOSO2
NH3
NO2
HNO3 H2SO4
O3
Gas PhaseFine Particles
hv
OH
O3
OH
OHHO2RO2
NO3
PMfine
SO4
PMfine
H2O2O3Fe
NO3
PMcoarse
SO4
PMcoarse
Coarse Particles
O3NO3
N2O5
H2OHeterogeneous
Yorkville Jan02 (9 Day) CMAQ Comparisons
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0 4 8 12 16 20 24
Hour (EST)
HNO
3 Av
erag
e (p
pb)
NewHeteroRxn NewHet-CB4 NoHeteroRxn YRKHNO3
Suburban Atlanta: HNO3(average diurnal cycle)
•Daytime over-production of HNO3 is also an issue
Schenley Park Jan02 (3.5 Week) CMAQ Comparisons
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
0 4 8 12 16 20 24
Hour (EST)
gasH
NO3
Aver
age
(ug/
m3)
02Release NewHeteroRxn NoHeteroRxn SCHPKHNO3
•Same behavior of HNO3 overprediction is observed at Pittsburgh.•The overprediction of HNO3 appears relatively smaller in summer (no daytime issue) than in winter. Winter may have bigger issues.
Pittsburgh: Winter Atlanta: Summer
Jefferson Street Aug99 HNO3 Diurnal Average Comparison
0123456
789
10
0 4 8 12 16 20 24
Hour (EST)
HNO
3 (p
pb)
JSTHNO3 02ModelHNO3 H3uModelHNO3
Fig. Difference in predictions of aerosol NO3
- with observed and modeled (MM5) temperatures at the Pittsburgh site
0
2
4
6
8
10
0 2 4 6 8 10
NO
3- (M
M5
T)
NO3
- (observed T)
-10
-5
0
5
10
15
20
25
-10 -5 0 5 10 15 20 25
MM
5 T
(C)
observed T (C)Time (EST, 2002)
-10-505
10152025
1/2 1/6 1/10 1/14 1/18 1/22 1/26 1/30
Observed TemperatureMM5 Temperature
Tem
pera
ture
(C)
0
2
4
6
8
10
1/2 1/6 1/10 1/14 1/18 1/22 1/26 1/30
NO3 (observed Temperature)NO3 (MM5 Temperature)
NO
3- (
g m
-3)
Comparison of Gas Ratio Frequency for Pittsburgh January 2002 (1/5/02 - 1/29/02)
020406080
100120140160180
<0 0.5 1.0 1.5 2.0 3.0 >3
Bin Range
2-H
ourly
Bin
Cou
nt
Schenley ParkH3uModGasRatioZeroModGasRatio02ModGasRatio
PittsburghFull Period
The CMAQ O3 Release is best even though it has biases. CMAQ with Zero N2O5 is not as good even though its total-Nitrate looks best.
Comparison of Gas Ratio Frequency for St LouisJanuary 4 - 30, 2002
0
2
4
6
8
10
12
14
0.5 1 1.5 2 3 4 >4
Gas Ratio Bin Range
Dai
ly A
vera
ge B
in C
ount
Stl-SSObsH3uMod03RelZeroN2O5Mod
The CMAQ O3 Release is worst (02 CMAQ Release would be much worse). CMAQ with Zero N2O5 is closest to Observations
St Louis