Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 1601-1619, 2015
https://doi.org/10.5194/acp-15-1601-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
16 Feb 2015
Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling
W. Tang1,*, D. S. Cohan1, A. Pour-Biazar2, L. N. Lamsal3,4, A. T. White5, X. Xiao1, W. Zhou1, B. H. Henderson6, and B. F. Lash1 1Department of Civil and Environmental Engineering, Rice University, 6100 Main Street MS 519, Houston, TX 77005, USA
2Earth System Science Center, University of Alabama, Huntsville, AL, USA
3NASA Goddard Space Flight Center, Greenbelt, MD, USA
4Goddard Earth Sciences Technology & Research, Universities Space Research Association, Columbia, MD, USA
5Department of Atmospheric Science, University of Alabama, Huntsville, AL, USA
6Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL, USA
*now at: Chinese Research Academy of Environmental Sciences, Beijing, China
Abstract. Uncertain photolysis rates and emission inventory impair the accuracy of state-level ozone (O3) regulatory modeling. Past studies have separately used satellite-observed clouds to correct the model-predicted photolysis rates, or satellite-constrained top-down NOx emissions to identify and reduce uncertainties in bottom-up NOx emissions. However, the joint application of multiple satellite-derived model inputs to improve O3 state implementation plan (SIP) modeling has rarely been explored. In this study, Geostationary Operational Environmental Satellite (GOES) observations of clouds are applied to derive the photolysis rates, replacing those used in Texas SIP modeling. This changes modeled O3 concentrations by up to 80 ppb and improves O3 simulations by reducing modeled normalized mean bias (NMB) and normalized mean error (NME) by up to 0.1. A sector-based discrete Kalman filter (DKF) inversion approach is incorporated with the Comprehensive Air Quality Model with extensions (CAMx)–decoupled direct method (DDM) model to adjust Texas NOx emissions using a high-resolution Ozone Monitoring Instrument (OMI) NO2 product. The discrepancy between OMI and CAMx NO2 vertical column densities (VCDs) is further reduced by increasing modeled NOx lifetime and adding an artificial amount of NO2 in the upper troposphere. The region-based DKF inversion suggests increasing NOx emissions by 10–50% in most regions, deteriorating the model performance in predicting ground NO2 and O3, while the sector-based DKF inversion tends to scale down area and nonroad NOx emissions by 50%, leading to a 2–5 ppb decrease in ground 8 h O3 predictions. Model performance in simulating ground NO2 and O3 are improved using sector-based inversion-constrained NOx emissions, with 0.25 and 0.04 reductions in NMBs and 0.13 and 0.04 reductions in NMEs, respectively. Using both GOES-derived photolysis rates and OMI-constrained NOx emissions together reduces modeled NMB and NME by 0.05, increases the model correlation with ground measurement in O3 simulations, and makes O3 more sensitive to NOx emissions in the O3 non-attainment areas.

Citation: Tang, W., Cohan, D. S., Pour-Biazar, A., Lamsal, L. N., White, A. T., Xiao, X., Zhou, W., Henderson, B. H., and Lash, B. F.: Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling, Atmos. Chem. Phys., 15, 1601-1619, https://doi.org/10.5194/acp-15-1601-2015, 2015.
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Short summary
A joint application of multiple satellite-derived model inputs to improve Texas O3 SIP modeling is demonstrated in this study. The GOES-retrieved clouds are applied to correct the modeled photolysis rates, and the DKF inversion approach is incorporated into the CAMx-DDM model to adjust NOx emissions using OMI NO2. Using both GOES-derived photolysis rates and OMI-constrained NOx emissions together improves O3 simulations and makes O3 more sensitive to NOx emissions in the O3 non-attainment areas.
A joint application of multiple satellite-derived model inputs to improve Texas O3 SIP modeling...
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