气候变化领域集成服务门户(CCPortal): Using satellite observations of tropospheric NO2 columns to infer long-term trends in US NOx emissions: The importance of accounting for the free tropospheric NO2 background

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DOI	10.5194/acp-19-8863-2019
	Using satellite observations of tropospheric NO2 columns to infer long-term trends in US NOx emissions: The importance of accounting for the free tropospheric NO2 background
	Silvern R.F.; Jacob D.J.; Mickley L.J.; Sulprizio M.P.; Travis K.R.; Marais E.A.; Cohen R.C.; Laughner J.L.; Choi S.; Joiner J.; Lamsal L.N.
发表日期	2019
ISSN	16807316
起始页码	8863
结束页码	8878
卷号	19 期号:13
英文摘要	The National Emission Inventory (NEI) of the US Environmental Protection Agency (EPA) reports a steady decrease in US NOx emissions over the 2005-2017 period at a rate of 0.1TgNa-1 (53% decrease over the period), reflecting sustained efforts to improve air quality. Tropospheric NO2 columns observed by the satellite-based Ozone Monitoring Instrument (OMI) over the US show a steady decrease until 2009 but a flattening afterward, which has been attributed to a flattening of NOx emissions, contradicting the NEI. We show here that the steady 2005-2017 decrease in NOx emissions reported by the NEI is in fact largely consistent with observed network trends of surface NO2 and ozone concentrations. The OMI NO2 trend is instead similar to that observed for nitrate wet deposition fluxes, which is weaker than that for anthropogenic NOx emissions, due to a large and increasing relative contribution of non-anthropogenic background sources of NOx (mainly lightning and soils). This is confirmed by contrasting OMI NO2 trends in urban winter, where the background is low and OMI NO2 shows a 2005-2017 decrease consistent with the NEI, and rural summer, where the background is high and OMI NO2 shows no significant 2005-2017 trend. A GEOS-Chem model simulation driven by NEI emission trends for the 2005-2017 period reproduces these different trends, except for the post-2009 flattening of OMI NO2, which we attribute to a model underestimate of free tropospheric NO2. Better understanding is needed of the factors controlling free tropospheric NO2 in order to relate satellite observations of tropospheric NO2 columns to the underlying NOx emissions and their trends. Focusing on urban winter conditions in the satellite data minimizes the effect of this free tropospheric background. © 2019 Copernicus GmbH. All rights reserved.
语种	英语
scopus关键词	air quality; EOS; nitrogen dioxide; ozone; satellite data; seasonality; trend analysis; troposphere; wet deposition; United States
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/144283
作者单位	Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States; School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States; Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom; Department of Chemistry, University of California, Berkeley, CA, United States; Department of Earth and Planetary Science, University of California, Berkeley, CA, United States; Science Systems and Applications Inc., Lanham, MD, United States; NASA Goddard Space Flight Center, Greenbelt, MD, United States; Goddard Earth Sciences Technology and Research, Universities Space Research Association, Columbia, MD, United States; NASA Langley Research Center, Hampton, VA, United States; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States
推荐引用方式 GB/T 7714	Silvern R.F.,Jacob D.J.,Mickley L.J.,et al. Using satellite observations of tropospheric NO2 columns to infer long-term trends in US NOx emissions: The importance of accounting for the free tropospheric NO2 background[J],2019,19(13).
APA	Silvern R.F..,Jacob D.J..,Mickley L.J..,Sulprizio M.P..,Travis K.R..,...&Lamsal L.N..(2019).Using satellite observations of tropospheric NO2 columns to infer long-term trends in US NOx emissions: The importance of accounting for the free tropospheric NO2 background.Atmospheric Chemistry and Physics,19(13).
MLA	Silvern R.F.,et al."Using satellite observations of tropospheric NO2 columns to infer long-term trends in US NOx emissions: The importance of accounting for the free tropospheric NO2 background".Atmospheric Chemistry and Physics 19.13(2019).