Power Plant NOx Emissions Estimated by OMI Benjamin de Foy, Saint Louis University

AQAST-8, Georgia Tech, 2 Dec 2014

Regional Ag. Fires

Stratosphere/ Wild Fires

130 ppb at 280 hPa

90 ppb at 500 hPa

Flexpart Back-Trajectories and PVU Analysis Show Two Plumes of Different Origins in SEAC4RS Ozonesonde Profile

Joseph Wilkins, Benjamin de Foy, Jack Fishman, Gary Morris

Back-Trajectories from upper plume (10km)

Ozonesonde, 30 Aug 2013

38.0;-90.0

EC/OC Emissions based on inverse model and hourly measurements in St. Louis: Diurnal and Monthly Profiles of Emissions

de Foy, B., Cui, Y. Y., Schauer, J. J., Janssen, M., Turner, J. R., and Wiedinmyer, C.: Estimating sources of elemental and organic carbon and their temporal emission patterns using a Least Squares Inverse model and hourly measurements from the St. Louis-Midwest Supersite, Atmos. Chem. Phys. Discuss.

Green: Weekday, Blue: Weekend Solid markers show LADCO Prior Inventory Shading shows uncertainty in inverse model results using bootstrapping Results obtained for On-Road, Non-Road, MAR, Point Sources and Other

Non-Road emissions have double peak in the monthly profile due to agricultural equipment use Inverse model suggests emissions are lower on weekends than current inventory

CAMx evaluation of different methods for estimating emissions from column data

Box Model Gaussian Fit EMG Fit Emissions Estimate: Linear dependence on plume speed estimate

Plume Speeds: Robust Speed-dependent bias

Stronger Winds

Plume Direction: Robust Omni-directional Accurate Plume Rotation

Chemistry: Required on input

Fairly Robust Somewhat Robust

Lifetime Estimate: Model Input Dispersion, very

short Chemical, biased

low

de Foy, Benjamin, et al. "Model evaluation of methods for estimating surface emissions and chemical lifetimes from satellite data." Atmospheric Environment 98 (2014): 66-77.

OMI Response to changing Power Plant NOx emissions

Duncan, Bryan N., et al. "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 81 (2013): 102-111.

The change in OMI Columns relative to the change in emissions (“response”) varies between power plants.

29 Power Plants with Isolated Plumes

Exponentially-Modified Gaussian Fit 2005-2011, ERA Interim surface winds

OMI BEHR, Rows 10-27, Oversampled to 4km grids Rotated grids (eastward plumes)

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.

Exponentially-Modified Gaussian Estimates of Emissions May-Sep 2005-2011, ERA Interim surface winds

OMI BEHR, Rows 10-27, Oversampled to 4km grids

Exponentially-Modified Gaussian Estimates of Lifetime vs. CEMS emissions

Lifetimes calculated by the EMG method are around 2 hours, which is too short to be representative of the chemical lifetime

Exponentially-Modified Gaussian Estimates of Emissions by year (May-Sep 2005-2011)

Whereas there was a good fit using averaged data for 2005-2011, the estimates start to degrade when using individual seasons.

Box Model Emissions Estimation 2005-2011, ERA Interim surface winds

OMI BEHR, Rows 10-27, Oversampled to 4km grids Rotated grids (eastward plumes) used for both EMG and Box Model

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

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𝜏𝜏

1𝜏𝜏

= 1

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1𝜏𝜏𝑐𝑐𝑐𝑑𝑑𝑐𝑐𝑑𝑑𝑑𝑑𝑐𝑐𝑑𝑑𝑐𝑐

Box Model Estimates of Emissions May-Sep 2005-2011, ERA Interim surface winds

Box model gives better estimate than EMG. Average column load based on 50km box. Background value based on median OMI column over 200km box. Chemical lifetime used in equation: 2 hours.

Chemical Lifetime that would give perfect match of emissions estimate (May-Sep 2005-2011):

Short lifetimes required to obtain good emissions estimates. This result was similar for winter and summer.

Box Model Emissions Estimates

Good fit for estimates for individual years

(May-Sep 2005-2011)

Emissions estimates for 2 month averages

(2005-2011)

Least-Squares Model to estimate chemical lifetime and wind-speed dependency based on CEMS data

Navajo, AZ Reliable fit of 2-month box model estimates.

Paradise, KY Winter vs. Summer emissions somewhat captured by box model.

Least-Squares Estimate of Winter vs. Summer Lifetimes

Longer Lifetime in Winter

Longer Lifetime in Summer

Regression method was not able to obtain improved lifetime estimates with the 2-month column averages of OMI data.

Power Plant NOx Emissions Estimated by OMI Benjamin de Foy, Saint Louis University

EMG gives reliable estimates for multi-

year time periods

EMG lifetimes were not found to be

representative of chemical reactivity

Box model gives accurate and robust estimates for 6 month periods or longer

Accuracy and reliability drop for 2 month period such that chemical lifetimes could not be inferred