Air quality has become the global issue with its impact on our society, economy, industry, diplomacy, public health and natural resources in addition to environmental science. Especially, Asia with its rapid increase in industrialization and population, has been regarded as an important source region of the global scale emission. Thus, it is crucial to monitor concentration of relevant gases and aerosols over Asia in high temporal and spatial resolution from geostationary orbit satellite. In 2009, National Institute of Environmental Research(NIER) of the Ministry of Environment, Korea has initiated the Geostationary Environmental Monitoring Spectrometer (GEMS) mission onboard the GEO-KOMPSAT 2B with its launch in 2019. GEMS is one of the three air quality monitoring missions over Asia, together with NASA’s TEMPO and ESA’s Sentinel-4. The objectives of the GEMS are:
To provide atmospheric chemistry measurements in high temporal and spatial resolution over Asia
To monitor regional transport events: transboundary pollution and Asia dust
To enhance our understanding on interactions between atmospheric chemistry and meteorology
To better understand the globalization of tropospheric pollution
To improve air quality forecast by: constraining emission rates / data assimilation of chemical observations
With the recent development of spectrometers in UV-visible with sub-nm spectral resolution and development of retrieval algorithms, we now can generate estimates of the column amounts of atmospheric O3, NO2, SO2, HCHO, CHOCHO and other constituents in the troposphere and stratosphere. To date, all the UV-visible satellite missions to monitor trace gas concentrations in the atmosphere have been in low Earth orbits (LEOs), usually allowing one observation per day. With the advent of the GEMS which is new UV-visible instruments on geostationary (GEO) platforms, the diurnal variation of these components now can be captured.