M. V. Glagolev

Regional methane emission from West Siberia mire landscapes

Methane emissions from mires in all climate–vegetation zones of West Siberia (forest steppe, subtaiga, south taiga, middle taiga, north taiga, forest tundra and tundra) were measured using a static chamber method. The observed fluxes varied considerably from small negative values in forested bogs and palsa to hundreds of mgC m −2 h −1 in ponds and wet hollows. Observed data were consolidated in the form of the empirical model of methane emissions designated as the ‘standard model’. The model is based on medians of CH4 flux distributions of eight different micro-landscape types depending on their location and estimated duration of methane emission period within the climate–vegetation zone. The current version (Bc8) of the ‘standard model’ estimates methane flux from West Siberia mires at 2.93 ± 0.97 TgC CH4 yr −1 that accounts for about 2.4% of the total methane emission from all mires or 0.7% of global methane emission from all sources.

Numerical modeling of methane emissions from lakes in the permafrost zone

A brief review of published observations of methane fluxes to the atmosphere from bogs and lakes in the permafrost zone is presented. Approaches to modeling the emission of methane from bogs are considered, and their advantages and shortcomings, in particular, from the point of view of their coupling to climate models, are outlined. A one-dimensional model developed by the authors for methane generation, transport, and sink in the ground-water body system and coupled to a hydrothermodynamic model of a water body is described. The approaches used in analogous models for bogs as well as new parametrizations describing lake-specific processes are applied. A parametrization of methane generation in vicinity the lower boundary of the thawed ground zone underneath a water body (talik) is suggested. The results of calibrating this model against available observations of methane emission from the thermokarst Shuchi Lake in northeastern Siberia are discussed.

Evaluation of methane emissions from West Siberian wetlands based on inverse modeling

West Siberia contains the largest extent of wetlands in the world, including large peat deposits; the wetland area is equivalent to 27% of the total area of West Siberia. This study used inverse modeling to refine emissions estimates for West Siberia using atmospheric CH4 observations and two wetland CH4 emissions inventories: (1) the global wetland emissions dataset of the NASA Goddard Institute for Space Studies (the GISS inventory), which includes emission seasons and emission rates based on climatology of monthly surface air temperature and precipitation, and (2) the West Siberian wetland emissions data (the Bc7 inventory), based on in situ flux measurements and a detailed wetland classification. The two inversions using the GISS and Bc7 inventories estimated annual mean flux from West Siberian wetlands to be 2.9 ± 1. 7a nd 3.0 ± 1. 4T g yr −1 , respectively, which are lower than the 6.3 Tg yr −1 predicted in the GISS inventory, but similar to those of the Bc7 inventory (3.2 Tg yr −1 ). The well-constrained monthly fluxes and a comparison between the predicted CH4 concentrations in the two inversions suggest that the Bc7 inventory predicts the seasonal cycle of West Siberian wetland CH4 emissions more reasonably, indicating that the GISS inventory predicts more emissions from wetlands in northern and middle taiga.

Seasonal variability as a source of uncertainty in the West Siberian regional CH4 flux upscaling

This study compares seasonal and spatial variations in methane fluxes as sources of uncertainty in regional CH4 flux upscaling from the wetlands of West Siberia. The study examined variability in summertime CH4 emissions from boreal peatlands, with a focus on two subtaiga fen sites in the southern part of West Siberia (Novosibirskaya oblast). We measured CH4 flux, water table depth, air and peat temperature, pH and electric conductivity of peat water during three field campaigns in summer 2011 (9‐12 July, 26‐28 July and 20‐21 August). Fluxes were measured with static chambers at sites chosen to represent two of the most widespread types of wetlands for this climatic zone: soligenous poor fens and topogenous fens. In both sites the water table level acts as the primary control on fluxes. For the poor fen site with good drainage, water table controls CH4 fluxes on the seasonal scale but not on a local spatial scale; for the fen site with weak drainage and microtopographic relief, the water table controls fluxes on the local spatial scale, but does not drive seasonal variations in the flux magnitude. This difference in hydrology shows the necessity of including detailed wetland type classification schemes into large-scale modeling efforts. From these three measurement periods, we estimated the relative seasonal variation in CH4 emissions as 8% for the fen site and 26% for the poor fen site. These results were compared to estimates of other sources of uncertainty (such as interannual variation and spatial heterogeneity) to show that quantifying seasonal variability is less critical than these other variations for an improved estimate of regional CH4 fluxes. This research demonstrates and ranks the challenges in upscaling measured wetland CH4 fluxes across West Siberia and can guide future field campaigns.

Methane emission from mires of the West Siberian taiga

In the summer-autumn seasons of 2007–2011, the methane emission from typical mire landscapes of Western Siberia was studied using the static chamber method. The lowest methane flux turned out to be characteristic of the ryams (pine-dwarf shrub-sphagnum associations) and the ridges of the ridge-hollow complexes, as well as of the wetland lakes in the northern and middle taiga (the medians are within the range of 0.1–0.5 mg C-CH4/m2 h). Values that are 10 times higher are typical for the oligotrophic hollows, fens, peat mats, and poor fens in different subzones (the medians are 2 to 7 mg C-CH4/m2 h). The maximal values of the methane flux from the wetland lakes of the southern taiga are 17.98 mg C-CH4/m2 h. Based on the data obtained by the authors, along with the previously published ones, the regional methane fluxes from the taiga mires were calculated: 2.22 Mt C-CH4/m2 per year, or about 80% of the total methane flux from the West Siberian mires. The estimates of the CH4 regional flux obtained by other researchers are discussed; the main source of the estimation uncertainty is analyzed.

Methane emissions from subtaiga mires of Western Siberia: The “standard model” Bc5

The observational data of methane emissions from typical peatland microlandscapes of Western Siberian subtaiga are summarized. These data are generalized using a concept of the “standard model” of methane emission. The model includes methane emission periods, wetland typology map, and emission rate probability density distributions for typical ecosystems. Version Bc5 of this model estimates the annual emissions from subtaiga at 0.8 ± 0.6 MtC-CH4 (5.2 ± 3.0 MtC for all of Western Siberia).

A process-based model of methane consumption by upland soils

This study combines a literature survey andfield observation data in an ad initio attempt to construct a process-basedmodel ofmethane sink in upland soils including both the biological and physical aspects of the process. Comparison is drawn between the predicted sink rates and chamber measurements in several forest and grassland sites in the southern part ofWest Siberia. CH4 flux, total respiration, air and soil temperature, soilmoisture, pH, organic content, bulk density and solid phase density weremeasured during a field campaign in summer 2014. Twodatasets from literature were also used formodel validation. Themodeled sink rates were found to be in relatively good correspondence with the values obtained in the field. Introduction of the rhizosphericmethanotrophy significantly improves thematch between themodel and the observations. TheQ10 values ofmethane sink observed in the fieldwere 1.2–1.4, which is in good agreementwith the experimental results from the other studies. Based onmodeling results, we also conclude that soil oxygen concentration is not a limiting factor formethane sink in upland forest and grassland ecosystems.

Methane emissions from north and middle taiga mires of Western Siberia: Bc8 standard model

During summer and autumn of 2008–2010 in the north and middle taiga, measurements of methane emissions from different types of wetland landscapes in Khanty-Mansi and Yamalo-Nenets Autonomous Okrugs were made by the static chamber method. Total methane emission from West-Siberian northern and middle taiga mires is estimated at 550 and 530 kt C-CH4 per year.

Relationship of methane consumption with the respiration of soil and grass-moss layers in forest ecosystems of the southern taiga in Western Siberia

The consumption of methane by some soils in the southern taiga of Western Siberia was studied by the static chamber method in the summer of 2013. The median of the specific CH4 flux through the soil was −0.05 mg C/(m2 h) for the entire set of measurements (the negative flux indicates the consumption of methane by the soil). A statistically significant (R2 = 0.81) linear relationship has been found between the specific CH4 flux to the soil and the total respiration of the soil and the grass-moss layers in the studied forest ecosystems. The quantitative theoretical explanation of this relationship is based on the plant-associated and free methanotrophy.

Measurements of methane and carbon dioxide fluxes on the Bakchar bog in warm season

Data terrain-atmosphere fluxes of methane and carbon dioxide overseen for measurement campaign Plotnikovo-2014 on the bog’s Flux-NIES automatic complex (N56°51.29’ E82° 50.91’) in the warn season. Six vegetative groups on the bog’s surface were taken in comparison. Improvement precise method used to determinate the sensitivity for the gases analyzers and calculating of the CO2 and CH4 fluxes measured by automated chamber-based technique.