Reconstruction of the methane fluxes from the west Siberia gas fields by the 3D regional chemical transport model

A 3D mesoscale tropospheric photochemical transport model of high spatial resolution has been developed and used for assessment of the methane concentrations and methane emission in the West Siberian region of intensive mining of natural gas and oil deposits. The model is validated against the measurements of methane concentration at the surface and in the lower troposphere collected during July 1993 and June 1996 experiments. Comparison of the simulated and observed concentrations allowed to estimate that during the above periods the average natural methane fluxes were as high as 65 mg m⁻² day⁻¹. The anthropogenic methane fluxes (leakage from gas deposits) integrated over model domain during the same time period were about 20% of the total methane emission from relevant areas.     

Methane Fluxes in West Siberia: 3-D Regional Model Simulation

The West Siberian region is one of the main contributors of theatmospheric greenhouse gas methane due to the large areas ofwetlands, rivers, lakes and numerous gas deposits situated there.But there are no reliable estimations of integral methane flux fromthis area into the atmosphere. For assessment of methane fluxes inWest Siberia the specially constructed 3-D regional chemicaltransport model was applied. The 3-D distribution of methane iscalculated on the basis of the current meteorological data fields(wind, temperature, geopotential) updated 4 times a day. The methaneconcentrations measured near the main gas fields of West Siberia inthe summer season of 1999, were used for correction of methane fluxintensity estimates obtained previously by comparison ofmeasurements carried out in summer 1993 and 1996 with modelledmethane mixing ratio distribution. This set of field and modelexperiments confirmed the preliminary conclusion about low leakageintensity: anthropogenic methane flux does not exceed 5–15% oftotal summer methane flux, estimated as 11–12 Mt CH₄ in summer from this region, in spite of the large areas of gas deposits located there.     

Long-term seasonal polymorphism of the Krasnodar greenbug population for virulence to sorghum varieties carrying different resistance genes

The genetic structure of the Krasnodar population of the greenbug (Schizaphis graminum Rondani) was analyzed in 2002 to 2010. A high level of general and seasonal polymorphism for the insect virulence to different sorghum accessions was revealed. Abiotic factors were shown to play an important role in the seasonal variation of the frequencies of virulence phenotypes: they can alter the relative competitiveness of greenbug clones, and, therefore, changes in environmental conditions lead to differential selection in the S. graminum population.