Aerosol Property Retrieval and Applications in Air Quality Monitoring from Geostationary Orbit Using GOCI and AHI

Aerosol properties have been retrieved extensively by numerous satellite instruments from both Low Earth Orbit (LEO) and Geostationary Earth Orbit (GEO). Sophisticated retrieval algorithms have been available with visible channel onboard conventional meteorological imager including GOES, METEOSAT, MTSAT and COMS. With the advent of next-generation, meteorological and ocean color imager onboard GEO platforms, aerosol properties became available in unprecedented temporal and spatial resolution. Multiple channels in visible and near IR from GEO satellite instruments with full disk imaging in 10 minutes made it possible to track fine structures of aerosol plumes in km resolution. These GEO aerosol products retrieved show much higher number of data points than the LEO, and were demonstrated successfully through extensive field campaigns including DRAGON-NE Asia in 2012, KORUS-AQ in 2016 and EMERGE-Asia in 2018. Their validation against ground-based AERONET show comparable statistics with those of LEO products. Geostationary Ocean Color Imager (GOCI) in particular has provided extensive aerosol dataset over East Asia, and even provide long-term trends. Due to high demands for data assimilation, these GEO products are now available in near real-time. Application of the GEO dataset has been extended to surface PM retrieval, air quality forecast through data assimilation, and public health studies.

Data merging among different GEO instruments at various level of retrieval shows possibility to significantly improve the data quality in the near future. In 2019-2020, GOCI-2 will be launched in GEO with a UV channel in 250 m resolution and enhance the accuracy of single scattering albedo (SSA) retrieval. The launch of a hyperspectral UV-Visible instrument, Geostationary Environment Monitoring Spectrometer (GEMS) together with GOCI-2 can add absorbing aerosol information by using UV channels and aerosol layer height information by using O2O2 absorption, in addition to measurements of aerosol precursors including NO2, SO2, HCHO etc. New era of GEO observation of aerosol properties is being realized and are to be expanded in many different areas of application.