Thesis of N.A. Shnyrev: II. Principal notes

This paper discusses in our opinion erroneous method of methane flux measurement, proposed in the dissertation of Nikolai Andreevich Shnyrev «Regime investigations and estimate of gas exchange on the soil-atmosphere interface (methane fluxes from “Muhrino” wetland, West Siberia». Principal error of suggested method is introduced by ill-posed nature of solved inverse problem. Ill-posed inverse problems are usual in environmental and Earth science applications. The main property of such kind of problems is high sensitivity of solution to changes in the initial data, which are often known with some uncertainty. Numerical test was conducted to proof that proposed by N.A. Shnyrev method is ill-posed. This test reveals, that flux value calculated with ahelp of N.A. Shnyrev’s method has an opposite sign and is three times higher in absolute value than flux, initially used in numerical test. In addition, proposed by N.A. Shnyrev method does not take into account non-linearity of gas diffusion coefficient along soil profile. Analogous proposed method of flux calculation during a cold season using methane concentration profile in a snow is also biased by several errors. Flux determination with this method leads to different results depending on the type of used gas transfer model. Besides evaluation of profile method several points about scientific ethics, citation without references, erroneous calculation of methane photolysis during chamber measurements are discussed.

methane emission, wetlands, inverse ill-posed problems, profile method