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Validation of GEMS operational v2.0 total column NO2 and HCHO during the GMAP/SIJAQ campaign

dc.contributor.authorBae, K.
dc.contributor.authorSong, C.K.
dc.contributor.authorVan Roozendael, M.
dc.contributor.authorRichter, A.
dc.contributor.authorWagner, T.
dc.contributor.authorMerlaud, A.
dc.contributor.authorPinardi, G.
dc.contributor.authorFriedrich, M.M.
dc.contributor.authorFayt, C.
dc.contributor.authorDimitropoulou, E.
dc.contributor.authorLange, K.
dc.contributor.authorand Bösch, T.
dc.contributor.authorZilker, B.
dc.contributor.authorLatsch, M.
dc.contributor.authorBehrens, L.K.
dc.contributor.authorZiegler, S.
dc.contributor.authorRipperger-Lukosiunaite, S.
dc.contributor.authorKuhn, L.
dc.contributor.authorLauster, B.
dc.contributor.authorReischmann, L.
dc.contributor.authorUhlmannsiek, K.
dc.contributor.authorCede, A.
dc.contributor.authorTiefengraber, M.
dc.contributor.authorGebetsberger, M.
dc.contributor.authorPark, R.J.
dc.contributor.authorLee, H.
dc.contributor.authorHong, H.
dc.contributor.authorChang, L.S.
dc.contributor.authorJeon, K.
dc.date2025
dc.date.accessioned2025-04-18T09:31:26Z
dc.date.available2025-04-18T09:31:26Z
dc.identifier.urihttps://orfeo.belnet.be/handle/internal/14019
dc.descriptionThe Geostationary Environmental Monitoring Spectrometer (GEMS), the first geostationary air quality instrument, onboard the GEO-KOMPSAT-2B (GK2B) satellite, produces hourly observations over Asia with 3.5 km × 8 km spatial resolution. To evaluate the GEMS L2 products, the National Institute of Environmental Research (NIER) organized the GEMS Map of Air Pollutants 2021 (GMAP2021) and the Satellite Integrated Joint monitoring of Air Quality 2022 (SIJAQ2022) campaigns during October 2021 to November 2021 and from June 2022 to July 2022, respectively. While GMAP2021 mainly targeted the SMA (Seoul Metropolitan Area), the SIJAQ2022 campaign extended to the southeastern area of South Korea. In this study, a comparison between Pandora and Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) products and an evaluation of the GEMS operational v2.0 total column NO2 and HCHO products are conducted. A comparative analysis between the Pandora (P189) and the IUP Bremen MAX-DOAS instrument at the Incheon NIER-ESC site was performed to analyze discrepancies between the retrieval processors (Pandora: PGN official processor, MAX-DOAS: MMF in FRM4DOAS framework). Aligning the viewing directions of both Pandora and MAX-DOAS leads to a significant increase in the slope and correlation coefficient from 0.87 to 0.96 and from 0.86 to 0.96, respectively, in the case of NO2 tropospheric columns. Similarly, for HCHO tropospheric columns, slope and correlation coefficient change from 0.94 to 1.09 and from 0.81 to 0.90 when matching the viewing geometries of both instruments. In contrast to tropospheric columns, total HCHO columns derived from Pandora (P189) direct-sun measurements show significantly larger values than the MAX-DOAS ones, with a mean relative difference (MRD) of 126 %. This bias can however be reduced to 33 % after suitable adjustment of the direct-sun retrieval settings. The GEMS v2.0 NO2 total column product, evaluated over 6 official PGN sites in South Korea, shows good agreement with a correlation coefficient of 0.87 and similar seasonal and diurnal NO2 variation. However, GEMS tends to report higher values than Pandora with a mean relative difference of +41 %. The magnitude of the GEMS overestimation is amplified in highly polluted conditions (i.e. during winter and at noontime). Compared to 6 MAX-DOAS stations and 6 Pandora stations, the GEMS HCHO product captures well the seasonal and diurnal variation of HCHO and shows good agreement both with MAX-DOAS and Pandora with slopes of 0.84 and 0.79, respectively, and correlation coefficients of 0.86 for both. Large columns, however, tend to be systematically underestimated.
dc.languageeng
dc.titleValidation of GEMS operational v2.0 total column NO2 and HCHO during the GMAP/SIJAQ campaign
dc.typeArticle
dc.subject.frascatiEarth and related Environmental sciences
dc.audienceScientific
dc.subject.freeChina
dc.subject.freeSeoul [South Korea]
dc.subject.freeSouth Korea
dc.subject.freeAcid rain
dc.subject.freeDamage detection
dc.subject.freeEmission control
dc.subject.freeFiber optic sensors
dc.subject.freeFog
dc.subject.freeHigh speed cameras
dc.subject.freeImage resolution
dc.subject.freeIonosphere
dc.subject.freeLiquid level indicators
dc.subject.freeMotion picture cameras
dc.subject.freeNetwork performance
dc.subject.freeOutages
dc.subject.freeOzone layer
dc.subject.freeSpectrometers
dc.subject.freeStatistical process control
dc.subject.freeTemperature indicating cameras
dc.subject.freeTropics
dc.subject.freeTroposphere
dc.subject.freeformaldehyde
dc.subject.freenitrogen dioxide
dc.subject.freeDifferential optical absorption spectroscopy
dc.subject.freeDiurnal variation
dc.subject.freeEnvironmental Monitoring
dc.subject.freeGeostationary environmental monitoring spectrometer
dc.subject.freeGMAP/SIJAQ
dc.subject.freeMulti-Axis
dc.subject.freeMulti-axis differential optical absorption spectroscopy
dc.subject.freeMulti-Axis-
dc.subject.freePandora
dc.subject.freeValidation
dc.subject.freeair quality
dc.subject.freeatmospheric pollution
dc.subject.freeatomic absorption spectroscopy
dc.subject.freecorrelation
dc.subject.freediurnal variation
dc.subject.freegeostationary satellite
dc.subject.freenitrogen dioxide
dc.subject.freeseasonal variation
dc.subject.freeslope
dc.subject.freespatial resolution
dc.subject.freetroposphere
dc.subject.freeabsorption spectroscopy
dc.subject.freeair monitoring
dc.subject.freealgorithm
dc.subject.freeArticle
dc.subject.freecircadian rhythm
dc.subject.freeclimate change
dc.subject.freecomparative study
dc.subject.freeconceptual framework
dc.subject.freecorrelation coefficient
dc.subject.freemulti axis differential optical absorption spectroscopy
dc.subject.freepollution
dc.subject.freeradiation
dc.subject.freesatellite integrated joint monitoring of air quality
dc.subject.freeseasonal variation
dc.subject.freevalidation process
dc.subject.freeAir quality
dc.source.titleScience of the Total Environment
dc.source.volume974
dc.source.pageA179190
Orfeo.peerreviewedYes
dc.identifier.doi10.1016/j.scitotenv.2025.179190
dc.identifier.url


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