Tropospheric and stratospheric NO retrieved from ground-based Fourier-transform infrared (FTIR) measurements

Abstract

Abstract. Nitric oxide (NO) is a key active trace gas in the atmosphere, which contributes to form harmful ozone in the troposphere and to the destruction of ozone in the stratosphere. In this study, we present the NO retrieval from ground-based Fourier-transform infrared (FTIR) solar absorption spectrometry measurements at a polluted site (Xianghe, China) and a background site (Maïdo, Reunion Island). The degree of freedom (DOF) of the NO retrieval is 2.3±0.4 (1σ) at Xianghe and 1.3±0.1 at Maïdo. By looking at the FTIR NO retrievals at Xianghe and Maïdo, we find that the stratospheric NO partial column is large in summer as compared to winter at both sites, and the seasonal variation in the FTIR stratospheric NO partial columns is consistent with that observed by the co-located Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) satellite measurements. A large diurnal variation in the stratospheric NO partial column is observed by the FTIR measurements at Maïdo, with an increase from the early morning to about 14:00 local time and a decrease thereafter. Due to the low NO concentration near the surface, the FTIR NO retrieval is only sensitive to the stratosphere at Maïdo. The high NO mole fraction near the surface at Xianghe allows us to derive tropospheric and stratospheric NO partial columns separately, although the tropospheric column is very difficult to retrieve in summer (June–August) because of the high water vapor abundance. A good correlation is found between the NO observed by the FTIR measurements and other air pollutants (NO2 and CO) in the troposphere at Xianghe. It is the first study of a successful analysis of NO in the troposphere from a ground-based FTIR site. The tropospheric and stratospheric NO retrieval might be possible at other potential FTIR sites inside or near large cities with enhanced levels of NO near the surface.

Seasonal and Diurnal Variations in XCO2 Characteristics in China as Observed by OCO‐2/3 Satellites: Effects of Land Cover and Local Meteorology

“…Atmospheric CO 2 measurements can provide a top‐down constraint on the inference of carbon fluxes (Mitchell et al., 2023; L. Zhang et al., 2023a). Our investigation that using direct satellite‐based observations to study the XCO 2 variation in seasonal and diurnal cycles amplitude among different biomes gives some new insight into carbon cycle amplitude, to some extent, could also reduce the uncertainties caused by the new assumptions of source/sink inversion work (Kou et al., 2023) or machine learning methods (Sheng et al., 2023; Y. Wang, Yuan, et al., 2023; L. Zhang et al., 2022b). Further, this also indicates that future flux simulation studies should take into account the distinguished SCA variances across ecosystems to better constrain and optimize the ultimate simulation results.…”

Understanding the variations and sources of CO, C2H2, C2H6, H2CO, and HCN columns based on 3 years of new ground-based Fourier transform infrared measurements at Xianghe, China

“…A Bruker IFS 125HR spectrometer was installed at Xianghe in 2016 and started recording solar absorption spectra in June 2018 (Zhou et al, 2020(Zhou et al, , 2021. The mid-infrared spectra covering the spectral range from 1800 to 5500 cm −1 are recorded with an Indium antimonide (InSb) detector, cooled with liquid nitrogen.…”

“…Such FTIR measurements are compliant with the Network for Detection of Atmospheric Composition Change -InfraRed Working Group (NDACC-IRWG) (De Mazière et al, 2018) protocols. In contrast to most NDACC FTIR sites, which are located in remote areas, the Xianghe site is located in a highly populated area with strong anthropogenic emissions from fossil fuel and biofuels combustion among other sources (Yang et al, 2020;Zhou et al, 2021). In this study, we present the first time series of FTIR retrievals of CO, C 2 H 2 , C 2 H 6 , H 2 CO, and HCN at Xianghe, covering 3 years of measurements, and their use to inves- tigate the variations in CO, C 2 H 2 , C 2 H 6 , H 2 CO, and HCN columns on both seasonal and synoptic scales, as well as their correlations.…”

Variations and correlations of CO, C<sub>2</sub>H<sub>2</sub>, C<sub>2</sub>H<sub>6</sub>, H<sub>2</sub>CO and HCN columns derived from three years of ground-based FTIR measurements at Xianghe, China

“…Within the Network for Detection of Atmospheric Composition Change -InfraRed Working Group (NDACC-IRWG) (De Mazière et al, 2018) In contrast to most NDACC FTIR sites which are located at remote sites, the Xianghe site is located in a highly-populated area, with strong anthropogenic emissions, among others from fossil fuel and biofuels combustion (Yang et al, 2020;Zhou et al, 2021). In this study, we present the first timeseries of FTIR retrievals of CO, C 2 H 2 , C 2 H 6 , H 2 CO and HCN at Xianghe, covering three years of measurements, and their use to investigate the variations of CO, C 2 H 2 , C 2 H 6 , H 2 CO and HCN columns on both seasonal and synoptic scales, as well as their correlations.…”