Comparisons of Greenhouse Gas Observation Satellite Performances Over Seoul Using a Portable Ground-Based Spectrometer

Abstract

Satellites provide global coverage for monitoring atmospheric greenhouse gases, crucial for understanding global climate dynamics. However, their temporal and spatial resolutions fall short in detecting urban-scale variations. To enhance satellite reliability over urban areas, this study presents the first comprehensive analysis of long-term observations of column-averaged dry air mole fractions of CO2, CH4, and CO (XCO2, XCH4, XCO) using two ground-based fourier transform infrared spectrometers, EM27/SUNs, in a megacity. With over 2 years of observations, our study shows that EM27/SUN measurements can effectively capture the daily and seasonal variability of XCO2, XCH4, and XCO over Seoul, a megacity with complex topography and various emission sources. In addition, we use the advantage of having multiple greenhouse gas satellites targeting Seoul to compare with the EM27/SUNs. Our study highlights the importance of EM27/SUN observations in Seoul to identify the need for improvements in satellites to monitor greenhouse gas behaviors and emissions in urban areas. This study examines how accurately satellites can monitor greenhouse gases over urban atmospheres to understand climate change. While satellites are good at covering large areas, they struggle to detect changes in cities. To improve these setbacks, this study uses ground-based instruments to measure greenhouse gases over 2 years and test satellite reliability over Seoul, a megacity with various emission sources as well as a complex terrain for observation. This study shows that the newly developed ground-based instruments, EM27/SUNs, are effective in tracking daily and seasonal changes in greenhouse gas concentrations and are useful tools in improving the validity of satellite observations in urban areas. The study suggests that using ground-based observations in addition to satellite data adapted for urban area monitoring is important for understanding greenhouse gas emissions in major cities like Seoul. First results of long-term EM27/SUN measurements and satellite comparisons over Seoul EM27/SUN effective in monitoring greenhouse gases and assessing validity of satellite measurements over urban areas Satellites need higher resolutions and locally validated algorithms for urban monitoring