Atmospheric Radiation Laboratory
Yonsei University, Seoul, Korea
Yonsei University, Seoul, Korea
Air pollution is increasingly recognized as a global environmental challenge that requires understanding emission sources, atmospheric transport, and chemical transformation processes across local, regional, and global scales. Climate change is closely linked to air pollution through complex feedbacks involving radiation, atmospheric chemistry, and meteorology. Remote sensing provides a powerful capability to observe atmospheric composition over broad spatial domains with consistent coverage.
The primary focus of the Atmospheric Radiation Laboratory (ARL) is to advance the understanding of radiative transfer processes in the atmosphere and to quantify air quality and atmospheric composition using satellite and ground-based remote sensing techniques. Our major target species include aerosols (particulate matter), O₃, NO₂, SO₂, HCHO, and CO₂, which play critical roles in air pollution, climate forcing, and atmospheric chemistry.
Aerosols and reactive trace gases play central roles in the Earth system by regulating radiative forcing, modifying cloud processes, driving photochemical smog formation, and degrading air quality, thereby linking climate change, atmospheric chemistry, and public health. Our laboratory advances satellite-based atmospheric research by developing retrieval algorithms and applying multi-sensor observations - including GOCI, MODIS, OMI, and TROPOMI - to quantify the distributions of aerosols and key precursor gases such as NO₂, SO₂, HCHO, and ozone. We further integrate machine learning techniques to estimate surface concentrations from satellite products and implement data fusion frameworks that leverage big-data methodologies to improve retrieval accuracy and spatial coverage.
A major focus of our research is continuous, high-resolution monitoring of air pollution over Asia, a region experiencing rapid industrialization, urbanization, and rapidly evolving emission patterns. We play a leading role in the development of core data processing and inversion algorithms for the Geostationary Environmental Monitoring Spectrometer (GEMS), the world’s first geostationary air quality mission launched in 2020. By combining radiative transfer modeling, optimal estimation, differential optical absorption spectroscopy (DOAS), and artificial intelligence–based approaches, our work supports near-real-time monitoring of aerosols, precursor gases, transboundary pollution transport, dust events, and chemistry–meteorology interactions.
Together with NASA’s TEMPO mission (launched in 2023) and ESA’s Sentinel-4 mission (launched in 2025), GEMS forms the foundation of the global geostationary air quality constellation (GEO Ring), enabling continuous atmospheric composition monitoring across major regions of the Northern Hemisphere. Looking forward, we contribute to the expansion of this observing system toward global coverage through emerging initiatives in the Middle East and Africa (MEASMA), South America (GEO-SA), and Australia (GEO-AUS). Our research aims to deliver actionable satellite-based information that advances atmospheric science, improves air quality forecasting, and supports evidence-based environmental policy and public health protection.
Remote Sensing of Air Quality and Climate Change from Space
Analyzing satellite observations provides critical information on atmospheric composition over broad spatial scales. In our laboratory, we develop advanced retrieval algorithms for air pollutants, including aerosols and key trace gases such as SO₂, NO₂, O₃, as well as the greenhouse gas CO4 and CH4. These observations enable tracking the distributions of air pollutants and greenhouse gases with high spatiotemporal resolution and consistent accuracy through rigorous validation against ground-based measurements.
We have played a key role in aerosol monitoring from geostationary satellite missions, including the Geostationary Ocean Color Imager (GOCI) and the Advanced Meteorological Imager (AMI), demonstrating the scientific value of continuous, high-temporal-resolution observations. Building on this experience, we are now leading algorithm development efforts for the Geostationary Environment Monitoring Spectrometer (GEMS), including retrievals of gaseous species and aerosols, providing unprecedented capability for monitoring air quality and transboundary pollution across Asia.
Development of Retrieval Algorithm for Aerosols and Pollutant Gases
Aerosols and trace gases in the atmosphere absorb, scatter, and transmit solar and terrestrial radiation, leaving distinct spectral signatures in measured radiance. Observations across multiple spectral windows enable the retrieval of atmospheric concentrations and key physical and chemical properties. Inverse methods for deriving aerosol and trace gas information from hyperspectral measurements rely on radiative transfer modeling, spectroscopy, and inversion theory. The retrieved products are systematically validated using independent observations from ground-based, airborne, and satellite platforms.
Monitoring Ozone Layer and Trend Analysis
Systematic ozone observations in Korea began first at the Atmospheric Radiation Laboratory (ARL) at Yonsei University in 1984 with the installation of a Dobson spectrophotometer. Since then, ARL has maintained continuous ozone monitoring using Dobson (1984–present), Brewer spectrometer (1997–present), and PANDORA instruments (2016-present). This site, known as the Wolbong Ozone Observatory, is part of the World Meteorological Organization (WMO) Global Ozone Observing System (GO3OS) and is registered as Station No. 252.
Long-term datasets from this observatory have been used to analyze daily total ozone variations, vertical ozone profiles, and multi-decadal trends. In addition to ozone, ultraviolet radiation is routinely measured, including erythemally weighted UV and other biologically relevant action spectra including DNA damage, vitamin D production, and plant response.