Spatial-Temporal Changes of Methane Content in the Atmosphere for Selected Countries and Regions with High Methane Emission from Rice Cultivation

Irrigated and flooded rice is associated with methane (CH4) emissions. CH4 is one of the most important anthropogenic greenhouse gases (GHG) in the atmosphere. Nowadays, mapping CH4 content at a global scale is possible using satellite sensors. Sample of such a sensor is TROPOspheric Monitoring Instrument (TROPOMI) placed on the Sentinel-5 Precursor (Sentinel-5P) satellite board. In this study, the evaluation of spatial-temporal changes in CH4 content in the atmosphere for selected countries and regions with high CH4 emissions from rice cultivation in 2019-2021 was performed. Visual evaluation of the spatial variability on CH4 content for the total study period indicates higher CH4 content for almost all areas with high rice concentration. This was confirmed by positive correlations between CH4 content in the atmosphere and estimated GHG emissions from croplands analyzed separately for each studied country/region. In addition, seasonal changes in CH4 content in the atmosphere were observed. The lowest CH4 content was observed at the beginning of the year (for the first quarter of the year) and the highest for the third quarter of the year. Moreover, a long-term increase in CH4 was noticed. Regression analysis revealed that the mean increase in CH4 content in most of the studied regions/countries was about 15 ppb per year. CH4 content evaluated with the use of satellite data from Sentinel-5P is a reliable data source and can be used for the analysis of temporal changes at various spatial scales, including regions and countries.