Evaluation of temporal changes in methane content in the atmosphere for areas with a very high rice concentration based on Sentinel-5P data

Abstract

Rice cultivation is one of the main sources of methane (CH4) emission into the atmosphere. The research aimed to assess long–term and seasonal changes in CH4 content in the atmosphere in areas where rice production exceeds 30% of the area. These areas include India, Bangladesh, Myanmar and Indonesia. CH4 content was evaluated using the Sentinel–5P TROPOMI sensor on a monthly basis from February 2019 to January 2022. Long–term and seasonal changes were assessed using statistical methods such as regression analysis and time–series analysis. The results showed that the long-term trend indicates an increase in CH4 concentration. In the analyzed period, the average annual increase in the CH4 content in the atmosphere was highest in eastern India (Bihar and West Bengal areas) and Bangladesh, from 15.9 to 19.6 ppb per year, while in Myanmar (Ayeyarwady) and Indonesia (Java) it was much lower, 3.7 and 9.9 ppb, respectively. Seasonal variability in CH4 content in the atmosphere was characterized by a large annual amplitude in the rice regions of India (from 47 to 58 ppb) and was consistent with CH4 emissions during a typical rice growth cycle. The highest CH4 content was observed in late summer i.e., before rice harvest. The results of the Sentinel–5P measurements confirm the spatial–temporal variability of atmospheric CH4 content in regions with a high share of rice production.