«Standard model» Bc4 of CH4 emission from West Siberian mires

Methane is a significant «greenhouse gas» and is of fundamental importance in atmospheric photochemistry, as it regulates the formation of ozone and hydroxyl, which are responsible for the breakdown of most gases that are emitted into the atmosphere by natural and anthropogenic processes. Mires are the most important natural methane source. West Siberian mires belong to the biggest wetland area in the world and contribute essentially to the global methane emission.
The aim of this study was to summarize results of monitoring of regional methane emissions from Western Siberia, using an approach, which we name the "standard model" (SM), this paper describes the newest SM version at the moment - Bc8. SM consists of data about a duration of methane emission in each zone, digital map and the probability density distribution of the specific methane fluxes from typical ecosystems, based on experimental methane emission measurements. As an example, results of those measurements in forest-steppe fens of Western Siberia and sites description are presented. Methane fluxes were measured with static chamber technique during snow-free period of year. Different mire types have been classified into eight categories and emission were measured in seven climatic zones from forest-steppe to tundra.
Bc8 estimates the value of yearly methane emission from Western Siberia mires as 2.9 Mt C-CH4. Results obtained on the basis of the Bc8 give a logical picture of the geographical location of the main methane sources: emission has the maximum values in the southern taiga and subtaiga. Analysis of the probability density functions of specific fluxes from different mire types and climatic zones has shown that there are three types of probability density function of the specific methane fluxes: first, similar to lognormal with a single peak, second, which has two statistically significant peaks, and third, which has three or more statistically insignificant peaks. To understand how global warming influence on the methane emission from West Siberian mires, we can use models that describe the changes of the climatic zones boundaries. For this reason model assumed linear dependency between methane emission and mean air temperature of the previous month. That assumption probably has a physical reason because this dependency reflects influence of temperature wave on activity of methanogenic bacteria.

greenhouse gases emission, West Siberia, mires