Comparison of Total Column and Surface Mixing Ratio of Carbon Monoxide Derived from the TROPOMI/Sentinel-5 Precursor with In-Situ Measurements from Extensive Ground-Based Network over South Korea

Ukkyo Jeong,Hyunkee Hong

doi:10.3390/rs13193987

Abstract

Atmospheric carbon monoxide (CO) significantly impacts climate change and human health, and has become the focus of increased air quality and climate research. Since 2018, the Troposphere Monitoring Instrument (TROPOMI) has provided total column amounts of CO (CTROPOMI) with a high spatial resolution to monitor atmospheric CO. This study compared and assessed the accuracy of CTROPOMI measurements using surface in-situ measurements (SKME) obtained from an extensive ground-based network over South Korea, where CO level is persistently affected by both local emissions and trans-boundary transport. Our analysis reveals that the TROPOMI effectively detected major emission sources of CO over South Korea and efficiently complemented the spatial coverage of the ground-based network. In general, the correlations between CTROPOMI and SKME were lower than those for NO2 reported in a previous study, and this discrepancy was partly attributed to the lower spatiotemporal variability. Moreover, vertical CO profiles were sampled from the ECMWF CAMS reanalysis data (EAC4) to convert CTROPOMI to surface mixing ratios (STROPOMI). STROPOMI showed a significant underestimation compared with SKME by approximately 40%, with a moderate correlation of approximately 0.51. The low biases of STROPOMI were more significant during the winter season, which was mainly attributed to the underestimation of the EAC4 CO at the surface. This study can contribute to the assessment of satellite and model data for monitoring surface air quality and greenhouse gas emissions.

Highlights

Major sources of atmospheric carbon monoxide (CO) include the incomplete combustion of fossil fuels, biomass burning, and the oxidation of methane and non-methane hydrocarbons, predominately activated by the hydroxyl radical (OH)
The mean values of CTROPOMI for 2019 over South Korea are shown in Figure 2 and were binned to a comparable resolution of the Troposphere Monitoring Instrument (TROPOMI) (0.05◦ × 0.05◦ horizontal grid)
Values were observed in eastern South Korea, where the low CTROPOMI vales in Figure 2a were predominately observed over mountainous areas

Summary

Introduction

Major sources of atmospheric carbon monoxide (CO) include the incomplete combustion of fossil fuels, biomass burning, and the oxidation of methane and non-methane hydrocarbons, predominately activated by the hydroxyl radical (OH). CO is removed by photochemical oxidation, which consumes OH during the process [1,2], affecting the atmospheric cleansing capacity [2] and lifetime of methane (CH4 ) [3,4] This reaction produces greenhouse gases such as carbon dioxide (CO2 ) and tropospheric ozone (O3 ); CO is regulated by worldwide air quality standards and is designated a significant greenhouse gas with a radiative forcing of 0.23 W m−2 [5]. Owing to the moderate lifetime of CO, it is frequently utilized as a tracer for the propagation of pollution [7,8] For these reasons, the Monitoring Atmospheric Composition and Climate (MACC) project of the Global Monitoring for Environment and Security (GMES) program prioritized CO as an important chemical species for air quality and climate studies [9]

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