Seasonal Variability of Solar-Induced Fluorescence and Correlation with Greenhouse Gas across Different Land Cover in East Asia

Climate change is a significant global issue recognized as being primarily caused by greenhouse gases, making it essential to understand the various factors affecting the carbon cycle for effective problemsolving.This study uses satellite data to analyze Solar-Induced Fluorescence (SIF), a key indicator of photosynthetic activity.It investigates differences across various land types based on Moderate Resolution Imaging Spectroradiometer (MODIS) data.The analysis revealed seasonal variations and higher photosynthetic indices in forested areas, suggesting the presence of robust photosynthetic activity.Additionally, this research utilized ground observation greenhouse gas data to validate the data from foreign greenhouse gas observation satellites (GOSAT, GOSAT-2, OCO-2, OCO-3) and assessed the reliability of these observations.It confirmed that the concentration of carbon dioxide (CO 2 ) in the atmosphere in East Asia increased by an average of about 2.68 ppmv/year from 2019 to 2023.Correlation analysis between CO 2 concentration and SIF indicated a seasonal pattern where CO 2 concentrations increased from autumn to spring and decreased during the summer, while SIF recorded the highest values in summer and the lowest in winter, showing a negative correlation.In particular, different SIF values were observed across regions, and when comparing the annual average CO 2 increase rates according to photosynthetic activity, differences based on land type were identified.These results enhance our understanding of the complex interactions between atmospheric CO 2 concentrations and terrestrial ecosystems, providing important insights into the mechanisms through which ecosystems contribute to climate change mitigation.