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[B-4.1.2 Methane Emission Rate from Permafrost Area]

[Contact Person]

Gen Inoue
Principal Research Scientist
Atmospheric Division and Global Environment Division,
National Institute for Environmental Studies, Environment Agency Japan,
16-2 Onogawa, Tsukuba, Ibaraki 305, JAPAN
Phone +81-298-50-2402, Fax +81-298-50-2468
E-mail inouegen@nies.go.jp

[Total Budget for FY1994-1996]

41,818,000 Yen (FY1996 12,893,000 Yen)

[Abstract]

　The permafrost in Siberia contains much more ice than that in Alaska and Canada. The methane contained was formed in past after the last glacial period by microbiological process and enclosed in permafrost so called ice complex as bubbles. It is now thawing gradually and the methane contained in it is released to the atmosphere directly. From the methane contained, the thawing rate and the length of cliff where the ice complex is exposed directly to the atmosphere, the release rate of methane is estimated to be 2-10Tg yr^-1.
　The methane emission from tundra area, Tiksi at the mouth of Lena River, observed was dependent on both the soil temperature and the thawing depth of permafrost. The maximum of emission observed was 80mg m^-2 day^-1, and it is very dependent on the atmospheric temperature. Thus the global warming in future is expected to enhance the methane emission and cause a positive feedback.
　The methane emission from lakes above permafrost, so called alas, have been measured near Yakutsk. The emission from the rim of the lake occupies the main part and was 140mg m^-2 day^-1 for a large lake, about 500m in diameter to 160mg m^-2 day^-1 for a small lake, about 100m in diameter.
　The vertical profiles of dissolved methane in wetland have been obtained to understand the formation process of methane. The fermentation experiments suggest the importance of precursor formation process.

[Key Words]

Methane, Methane Fulx, Natural Wetland, Siberia