First observation of tropospheric nitrogen dioxide from the Environmental Trace Gases Monitoring Instrument onboard the GaoFen-5 satellite

Abstract

The Environmental Trace Gases Monitoring Instrument (EMI) is the first Chinese satellite-borne UV-Vis spectrometer aiming to measure the distribution of atmospheric trace gases on a global scale. The EMI instrument onboard the GaoFen-5 satellite was launched on 9 May 2018. In this paper, we present the tropospheric nitrogen dioxide (NO 2) vertical column density (VCD) retrieval algorithm dedicated to EMI measurement. We report the first successful retrieval of tropospheric NO 2 VCD from the EMI instrument. Our retrieval improved the original EMI NO 2 prototype algorithm by modifying the settings of the spectral fit and air mass factor calculations to account for the on-orbit instrumental performance changes. The retrieved EMI NO 2 VCDs generally show good spatiotemporal agreement with the satellite-borne Ozone Monitoring Instrument and TROPOspheric Monitoring Instrument (correlation coefficient R of~0.9, bias < 50%). A comparison with ground-based MAX-DOAS (Multi-Axis Differential Optical Absorption Spectroscopy) observations also shows good correlation with an R of 0.82. The results indicate that the EMI NO 2 retrieval algorithm derives reliable and precise results, and this algorithm can feasibly produce stable operational products that can contribute to global air pollution monitoring.

An improved TROPOMI tropospheric HCHO retrieval over China

“…The anthropogenic and biogenic emissions are obtained from the Multi-resolution Emission Inventory for China (MEIC) and the Model of Emissions of Gases and Aerosols from Nature (MEGAN) (Guenther et al, 2006;, respectively. The MEIC emission inventory has improved the emissions estimation from power plants (Liu et al, 2015), vehicles (Zheng et al, 2014) and residential combustion of non-methane volatile organic compounds (NMVOCs) Peng et al, 2019). The open burning emission is obtained from the Fire INventory from NCAR (FINN) model (Wiedinmyer et al, 2011).…”

Ozone profile retrievals from TROPOMI: Implication for the variation of tropospheric ozone during the outbreak of COVID-19 in China

“…Ozone has different effects at different altitudes in the atmosphere. Most of the ozone distributed in the stratosphere can absorb strong ultraviolet radiation that can cause health problems in humans ( Bell et al, 2004 ; Norval et al, 2007 ; Su et al, 2017 ; Nuvolone et al, 2018 ; Zhang et al, 2020 ). A small amount of ozone in the troposphere, which is mainly produced from the photochemical reaction between volatile organic compounds (VOCs) and nitrogen dioxides (NO x ) ( Littman and Magill, 1953 ; Sillman, 1995 ), shows harmful effects to humans.…”

Mapping the drivers of formaldehyde (HCHO) variability from 2015–2019 over eastern China: insights from FTIR observation and GEOS-Chem model simulation

“…The emitted HCHO is mainly attributed to incomplete combustion and is closely associated with the emissions of benzene (C9H12O), toluene (C7H8), or carbon monoxide (CO) (Friedfeld et al, 2002;Garcia et al 2006;Ma et al, 2016). In addition, photochemical formation of HCHO has been identified from the atmospheric oxidation of methane (CH4) and numerous nonmethane VOCs (NMVOCs), which are closely associated with the formation of ozone (O3) or Ox (O3 + nitrogen dioxide (NO2)) or glyoxal (CHOCHO) (Chapter 6, Seinfeld and Pandis, 2016;Friedfeld et al, 2002;Garcia et al 2006;Zhang et al, 2020). As a result, the relative contribution of emitted and photochemical sources to atmospheric HCHO can be estimated via a linear multiple regression analysis method that aims at reproducing the time series of observed HCHO from a linear combination of the time series of CO (or C9H12O or C7H8 ) and O3 (or Ox or CHOCHO) as tracers for emitted and photochemical HCHO, respectively (Friedfeld et al, 2002;Garcia et al, 2006;Hong et al, 2018;Li et al, 2010;Lui et al, 2017;Ma et al, 2016;Su et al, 2019).…”