Using OMI NO2 and CAMx
simulations to estimate emissions
from point and area sources
Benjamin de Foy, Saint Louis University
NASA Air Quality Applied Sciences Team 6th Meeting
15-17 January 2014, Rice University
Estimation of direct emissions and atmospheric processing
of reactive mercury using inverse modeling
B. de Foy, J.B. Heo, J. J. Schauer, Atmospheric Environment, 2014
Least-Squares Inversion combines Back-trajectories,
Forward Dispersion from Forest Fires and the Free Troposphere,
Chemical Tracers and a Chemical Box Model
Test Emissions Estimates using
WRF & CAMx simulations
Domain 1, 27km cell size
Year-long WRF simulations for 2005
Domain 2, 9km cell size
Emissions Estimation Methods:
Box Model / Gaussian Fit / ExponentiallyModified Gaussian Fit
Duncan, B. N., Yoshida, Y., de Foy, B., Lamsal, L. N., Streets, D. G., Lu, Z., & Krotkov, N. A. (2013). The
observed response of Ozone Monitoring Instrument (OMI) NO2 columns to NOx emission controls on power
plants in the United States: 2005–2011. Atmospheric Environment.
“Introduction to Atmospheric Chemistry”, Daniel Jacob
Emissions Estimation Methods:
Box Model / Gaussian Fit / ExponentiallyModified Gaussian Fit
Lu, Zifeng, et al. "OMI Observations of Interannual Increase in SO2 Emissions from Indian CoalFired Power Plants during 2005− 2012." Environmental science & technology (2013).
Fioletov, V. E., et al. "Estimation of SO2 emissions using OMI retrievals." Geophysical Research
Letters 38.21 (2011).
Emissions Estimation Methods:
Box Model / Gaussian Fit / ExponentiallyModified Gaussian Fit
Beirle, S., Boersma, K. F., Platt, U., Lawrence, M. G., & Wagner, T. (2011). Megacity emissions and
lifetimes of nitrogen oxides probed from space. Science, 333(6050), 1737-1739.
Valin, L. C., Russell, A. R., & Cohen, R. C. (2013). Variations of OH radical in an urban plume
inferred from NO2 column measurements. Geophysical Research Letters.
Simulation Test Cases: No Chemistry
Uniform Plume Directions
Idealized
Winds:
5m/s from
the West
(31 days)
WRF Winds
for 2005
(365 days)
Eastward Plumes
Simulation Test Cases: 1 hr Chemical Lifetime
Uniform Plume Directions
Idealized
Winds:
5m/s from
the West
(31 days)
WRF Winds
for 2005
(365 days)
Eastward Plumes
Emissions Estimation Methods: Box Model
Input
Box Model
Ideal
WRF
Emissions (kton/year)
No Chemistry
47.0
44.2
33.9
12-hr Chemistry
47.0
39.5
23.7
1-hr Chemistry
47.0
14.7
5.0
5
0 - 2.5
Wind Speed (m/s)
Average plume for 2005
interpolated to 2km grid
with box used for estimation
Emissions Estimation Methods:
Gaussian Fit
Average of 2005 Plume
2D Gaussian Fit
Emissions Estimation Methods:
Gaussian Fit
Input
Box Model
Ideal
Gaussian Fit
WRF
Ideal
WRF
Emissions (kton/year)
No Chemistry
47.0
44.2
33.9
47.9
55.5
12-hr Chemistry
47.0
39.5
23.7
48.2
49.3
1-hr Chemistry
47.0
14.7
5.0
36.4
22.6
5
0 - 2.5
5
0 - 2.5
Eastward
Uniform
Uniform
Uniform
Infinity
0.9
1.9
12-hr Chemistry
12
0.9
1.7
1-hr Chemistry
1
0.7
1.3
Wind Speed (m/s)
Plume Direction
Lifetime (hr)
No Chemistry
Emissions Estimation Methods:
Exponentially-Modified Gaussian Fit
No Chemistry, WRF Winds, Eastward Plume
1-hr Chemical Lifetime, WRF Winds, Eastward Plume
1D plot of the sum along
the y-axis of the rotated
plume
Emissions Estimation Methods:
Exponentially-Modified Gaussian Fit
Input
Box Model
Ideal
WRF
Gaussian Fit
Ideal
WRF
EMG Fit
Ideal
WRF
Emissions (kton/year)
No Chemistry
47.0
44.2
33.9
47.9
55.5
46.7
48.0
12-hr Chemistry
47.0
39.5
23.7
48.2
49.3
46.7
46.2
1-hr Chemistry
47.0
14.7
5.0
36.4
22.6
46.1
40.1
Wind Speed (m/s)
5
0 - 2.5
5
0 - 2.5
5
5 - 10
Plume Direction
Eastward Uniform Uniform Uniform Eastward Eastward
Lifetime (hr)
No Chemistry
Infinity
0.9
1.9
425
4000
12-hr Chemistry
12
0.9
1.7
11.4
10.2
1-hr Chemistry
1
0.7
1.3
1.0
1.1
Conclusions: Using OMI NO2 and CAMx simulations to
estimate emissions from point and area sources
Box Model
Emissions Estimate:
Plume Speeds:
Plume Direction:
Chemistry:
Lifetime Estimate:
Gaussian Fit
EMG Fit
Linear dependence on plume speed estimate
Robust
Weak Winds
Stronger Winds
Robust
Uniform
Dispersion
Accurate Plume
Rotation
Sensitive
Fairly Robust
Robust
Input to model Dispersion, very Chemical, biased
based on plume
short
low
speed and box
size
Benjamin de Foy, Saint Louis University