Correlation-Based Evaluation of GEMS Satellite Products Using Environmental and Meteorological Measurements

This study evaluated the reliability and applicability of the Geostationary Environment Monitoring Spectrometer (GEMS) data for monitoring atmospheric conditions in South Korea.This study analyzed correlations between GEMS satellite products (Aerosol Optical Depth [AOD], NO 2 , HCHO, Ozone Profile [O 3 P]), Airkorea ground-based data, Local Data Assimilation and Prediction System (LDAPS) meteorological data, and land cover map across 161 administrative districts from 2021 to 2023.Despite the satellite's low spatial resolution, analysis revealed significant correlations between GEMS observations and ground-based measurements.GEMS AOD showed strong negative correlations (-0.6) with atmospheric instability indices and positive correlations with ground PM 2.5 (0.57) and carbon monoxide (CO) (0.6) measurements in spring, while summer ozone measurements demonstrated high correlations with ground observations (0.6) and temperature (0.59).Particularly strong correlations were observed in spring and fall, with GEMS AOD showing a distinct positive correlation with ground Particulate Matter (PM) concentrations and a negative correlation with atmospheric instability.The study found varying correlation patterns across different land cover types: urban areas demonstrated high positive correlations between GEMS AOD and PM substances, while forest regions showed generally lower pollutant concentrations, confirming their air purification function.Seasonal analysis revealed complex patterns, with spring and fall showing more interpretable correlations between variables compared to summer.Interpreting correlation patterns in summer was difficult due to the unique atmospheric meteorological factors of the Korean Peninsula.Regional analysis showed effective capture of pollutant transport phenomena, particularly along the west coast where spring westerly winds influence pollution patterns.The study also found that meteorological conditions, especially Boundary Layer Height (BLH) and atmospheric instability, significantly influenced pollutant concentrations and their spatial distribution.These findings suggest that GEMS satellite data can effectively complement ground-based monitoring networks for comprehensive air quality assessment in South Korea, particularly in monitoring broad-scale pollution phenomena and tracking pollutant transport patterns.However, there are limitations to local spatial analysis and special meteorological phenomena, so satellite and ground observation data must be integrated to build an optimal air quality monitoring system.