Spatiotemporal distribution patterns of atmospheric methane using GOSAT data in Iran

摘要

Methane (CH_4) is the simplest hydrocarbon in the atmosphere and is the second most important greenhouse gas (GHG) after carbon dioxide (CO_2) whose concentration is changing due to human activities. The main objective of this study is to examine the spatial distribution of CH_4 concentration for Iran in 2013 based on the level 2 GOSAT data using the ordinary kriging technique. For this purpose, first, the relationship between CH_4 concentration and environmental variables such as land surface temperature (LST), normalized difference vegetation index (NDVI), air temperature, and humidity was determined. The results showed that CH_4 concentration changes gradually with latitude and longitude across Iran. The spatial distribution of CH_4 concentration presents the high concentration of this gas in the southern hemisphere and in the east of the study area throughout the year. The correlation of CH_4 concentration with LST and temperature was positive, and its correlation with NDVI and humidity was negative in different seasons of 2013. This implies that with the decline of temperature and LST and rise of humidity and NDVI, CH_4 concentration has decreased in the study area. It is possible to transfer the CH_4 gas from the south to the southeast of Iran according to the location of flaring gas, and wind speed and direction in different seasons. These findings can help decision makers for better management of the sinks and sources of GHGs.