GEO-KOMPSAT-2B

GEO-KOMPSAT-2B (GK-2B, Cheollian-2B) is a Korean geostationary satellite carrying ocean-colour and atmospheric-composition instruments, operated by the Korea Aerospace Research Institute at 128.2 degrees East and 35,786 km altitude.^[1] Launched on 18 February 2020 in UTC, the mission is operational as of the WMO OSCAR record updated 2025-01-16.^[1] The Geostationary Ocean Color Imager II (GOCI-II) provides 250 m resolution ocean-colour observations over a 2500 km local-area swath at hourly cadence during daylight hours, enabling coastal water quality monitoring, harmful algal bloom detection, and marine primary productivity assessment in Northeast Asian seas.^[2] The Geostationary Environment Monitoring Spectrometer (GEMS) observes tropospheric column NO2 and SO2 and related air-quality products across East and South Asia, covering long-range transport of air pollutants and industrial emissions at geostationary temporal resolution.^[3] The WMO OSCAR record gives launch on 2020-02-18 while the NIER Environmental Satellite Center describes GEMS aboard GK-2B as launched on 2020-02-19, consistent with the Korea local date.^[1][3]