DOI: 10.1016/j.atmosenv.2020.117341
论文题名: Revisiting the effectiveness of HCHO/NO2 ratios for inferring ozone sensitivity to its precursors using high resolution airborne remote sensing observations in a high ozone episode during the KORUS-AQ campaign
作者: Souri A.H. ; Nowlan C.R. ; Wolfe G.M. ; Lamsal L.N. ; Chan Miller C.E. ; Abad G.G. ; Janz S.J. ; Fried A. ; Blake D.R. ; Weinheimer A.J. ; Diskin G.S. ; Liu X. ; Chance K.
刊名: Atmospheric Environment
ISSN: 1352-2310
出版年: 2020
卷: 224 语种: 英语
英文关键词: Air quality
; Feedback
; Formaldehyde
; Indicators (chemical)
; Models
; Ozone
; Particulate emissions
; Remote sensing
; Volatile organic compounds
; Airborne instruments
; Airborne remote sensing
; Aircraft measurement
; Chemical relationships
; Mitigation strategy
; Ozone sensitivity
; Photochemical box model
; Sensor optimization
; Nitrogen oxides
; formaldehyde
; nitrogen dioxide
; ozone
; volatile organic compound
; aerosol composition
; airborne survey
; chemical composition
; formaldehyde
; nitrogen dioxide
; ozone
; remote sensing
; sensor
; volatile organic compound
; air pollution
; air quality
; aircraft
; Article
; calibration
; human
; measurement
; priority journal
; remote sensing
; South Korea
; Seoul [South Korea]
; South Korea
; United States
学科: Emissions
; Formaldehyde
; Modeling
; NO2
; Ozone sensitivity
; Remote sensing
中文摘要: The nonlinear chemical processes involved in ozone production (P(O3)) have necessitated using proxy indicators to convey information about the primary dependence of P(O3) on volatile organic compounds (VOCs) or nitrogen oxides (NOx). In particular, the ratio of remotely sensed columns of formaldehyde (HCHO) to nitrogen dioxide (NO2) has been widely used for studying O3 sensitivity. Previous studies found that the errors in retrievals and the incoherent relationship between the column and the near-surface concentrations are a barrier in applying the ratio in a robust way. In addition to these obstacles, we provide calculational-observational evidence, using an ensemble of 0-D photochemical box models constrained by DC-8 aircraft measurements on an ozone event during the Korea-United States Air Quality (KORUS-AQ) campaign over Seoul, to demonstrate the chemical feedback of NO2 on the formation of HCHO is a controlling factor for the transition line between NOx-sensitive and NOx-saturated regimes. A fixed value (~2.7) of the ratio of the chemical loss of NOx (LNOx) to the chemical loss of HO2+RO2 (LROx) perceptibly differentiates the regimes. Following this value, data points with a ratio of HCHO/NO2 less than 1 can be safely classified as NOx-saturated regime, whereas points with ratios between 1 and 4 fall into one or the other regime. We attribute this mainly to the HCHO-NO2 chemical relationship causing the transition line to occur at larger (smaller) HCHO/NO2 ratios in VOC-rich (VOC-poor) environments. We then redefine the transition line to LNOx/LROx~2.7 that accounts for the HCHO-NO2 chemical relationship leading to HCHO = 3.7 × (NO2 – 1.14 × 1016 molec.cm-2). Although the revised formula is locally calibrated (i.e., requires for readjustment for other regions), its mathematical format removes the need for having a wide range of thresholds used in HCHO/NO2 ratios that is a result of the chemical feedback. Therefore, to be able to properly take the chemical feedback into consideration, the use of HCHO = a × (NO2 – b) formula should be preferred to the ratio in future works. We then use the Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument to study O3 sensitivity in Seoul. The unprecedented spatial (250 × 250 m2) and temporal (~every 2 h) resolutions of HCHO and NO2 observations form the sensor enhance our understanding of P(O3) in Seoul; rather than providing a crude label for the entire city, more in-depth variabilities in chemical regimes are observed that should be able to inform mitigation strategies correspondingly. © 2020 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/160471
Appears in Collections: 气候变化与战略
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作者单位: Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States; NASA Goddard Space Flight Center, Greenbelt, MD, United States; University of Maryland Baltimore County, Baltimore, MD, United States; University Space Research Association, Goddard Earth Sciences Technology and Research (GESTAR), Columbia, MD, United States; Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, United States; Department of Chemistry, University of California, Irvine, Irvine, CA, United States; National Center for Atmospheric Research, Boulder, CO, United States; NASA Langley Research Center, Hampton, VA, United States
Recommended Citation:
Souri A.H.,Nowlan C.R.,Wolfe G.M.,et al. Revisiting the effectiveness of HCHO/NO2 ratios for inferring ozone sensitivity to its precursors using high resolution airborne remote sensing observations in a high ozone episode during the KORUS-AQ campaign[J]. Atmospheric Environment,2020-01-01,224