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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Methane in Upper Permafrost of Eastern Siberia: Sources and Significanceтезисы доклада
- Авторы: Brouchkov A., Fukuda M.
- Сборник: American Geophysical Union (AGU) 2002 Fall Meeting
- Серия: Eos, Transactions American Geophysical Union
- Том: 83
- Тезисы
- Год издания: 2002
- Номер статьи: B12A-0780
- Аннотация: Methane contribution to greenhouse effect is significant, so the production and concentrations of methane in great permafrost areas of Eurasia is in important respects analogous to the climate change forecast. Studies of the widespread methane should provide insight into the microbiological activity in permafrost. The total amount of methane trapped in permafrost is poorly studied; methane could disappear in unfrozen deposits, but not in ice-saturated soils. Gas samples were collected directly from upper permafrost of Lena river valley, Eastern Siberia. Frozen alluvial deposits in different landscapes were studied for methane and carbon dioxide content from the depths of up to 5 m. Ice wedges were also investigated. Measurements show different values; highest methane content was found in frozen mineral deposits (up to 6000 ppmv), but some soils almost do not contain methane. Ice wedges contain great amount of carbon dioxide. Ice wedges are presented by two categories: those with high methane content (generally, small wedges often with high mineral content) and those with almost no methane (ice wedges of big thickness). There was no correlation established between the methane content and depth. Average methane content in permafrost could be estimated as 0.05 - 0.5 ml/kg. Normally, icy permafrost contains more gas. In general, methane and carbon dioxide content increase with water content increase. The older the permafrost, the more methane it contains; this could be an indirect evidence of possible methane generation in the frozen state. Long-term experiments have shown that there is a slow production of methane in different frozen soils at -5°C. The change of methane content occurred according to logarithmical law in samples of modern soils from Alaska, Yakutsk and Hokkaido; the rates of methane production decrease in time, but methane could be produced in significant amounts in frozen soils, taking into account the age of permafrost.
- Добавил в систему: Брушков Анатолий Викторович