Findings of the Atmospheric Methane Study
The study, Spatiotemporal variations in mid-upper tropospheric methane over China from satellite observations, focused on the levels of CH4 in the lower atmosphere – a layer which, co-author Dr Zhang told Decoded Science, gives an indication of levels of anthropogenic emissions. A significant aspect of the research is the use of satellite remote sensing which, he said “can effectively compensate for the lack of surface scattered observations.”
The results of this study present a pattern of changing tropospheric methane levels over China in terms of space and time. Concentrations of CH4 were greater over areas of high population and lower where population is sparse, indicating a link to industrial and agricultural production.
Seasonal peaks in the north and east are attributable to biological sources in summer, (the rice-growing season) and non-biological sources in winter (fossil fuels for heating): winter weather conditions may have influenced this peak. Further south, there is no winter peak, possibly reflecting higher temperatures, while in the west, the low methane levels in winter reflect the limited population.
Population’s Effect on Atmospheric Methane
Overall, this study of atmospheric methane presents a picture of methane levels over a period of six years across China, and reflects a potential link between human activities (domestic, agricultural and industrial) and high levels of the gas in the troposphere, due to the notably lower levels where population is absent.
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Zhang, X.Y. et al. Spatiotemporal variations in mid-upper tropospheric methane over China from satellite observations. (2012). Chinese Science Bulletin. Accessed January 20, 2012.
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