Investigating national methane sources with satellite retrievals: a case of South Korea

Methane is the second largest greenhouse gas after carbon dioxide in its impact on climate change. Atmospheric methane has stagnated from 2000 to 2006, and then began to increase again in 2007, showing the largest increase since observation in 2021(19.94 ppb/yr).

As part of UNFCCC’s goals for carbon neutrality, it is necessary to verify each country's GHG’s emissions sources and the verifications using satellite observations and atmospheric models are one of the important approaches.

Currently, satellite data have been useful for methane monitoring, particularly the retrievals measured by TROPOMI with a high resolution(~7km) and good spatial coverage.

Here we investigated the spatio-temporal characteristics of national methane distribution and the spatial correlation between satellite concentrations and the national emission sources over South Korea to identify the characteristics of high-level methane distributions from August 2018 to July 2019 .

During the period, the average concentration of XCH4 in Korea was ~1858 ppb and the monthly mean concentrations of methane in Korea were higher from June to October, which in fact reflected the characteristics of rice paddy and wetlands in monsoon season.

The spatial correlation analysis (SDM) found that there are some areas showing specific contributing emissions sources with higher methane levels. There are areas with high correlations with livestock production, fossil fuel uses(gas & oils), wastes(& landfill), and rice paddies, while there are areas with high correlations with complex effects of the four fields or with no clear correlations.

Based on our analysis, the spatial correlation analysis with various emission sources and satellite data can provide the information to evaluate the CH4 emissions inventory and give some ideas to manage regional greenhouse gases reduction policies