The preliminary result of total column ozone observations from GEMS

Abstract:

The Geostationary Environment Monitoring Spectrometer (GEMS), launched on 18 February 2020, aboard the GEO-KOMPSAT-2B (GK-2B) satellite, measures earthshine radiance in the ultraviolet and visible spectral range (300~500 nm). We have been investigated the first hourly total ozone measurements from geostationary satellite for the period from June and July 2020, based on the TOMS version 9 algorithm, which retrieves total column ozone from a discrete wavelength in Huggins band (312.34, 317.34 and 331.02 nm) using the Rodger optimal estimation method. In order to evaluate the quality of GEMS TCO, we compare our results with the TCO obtained from the TROPOspheric Monitoring Instrument (TROPOMI) as well as Pandora measurements over Seoul and Busan. Although different spectral ranges and retrieval methods are used, we find a good agreement between the ozone products obtained from the two satellites with a mean difference of -0.82%, a standard deviation of 1.83%, and a correlation coefficient of 0.98. In addition to this, we have focused on validating how hourly total ozone is related to meteorological movement using twin meteorological satellite, GEO-KOMPSAT-2A, located next to GEO-KOMPSAT-2B. Our preliminary results also well capture elevated ozone induced by the weather system in mid-latitude.