ESTIMATION OF METHANE EMISSION IN ST. PETERSBURG AND ITS ENVIRONS FROM SURFACE CONCENTRATIONS

A. V. Zinchenko, N. N. Paramonova, V. I. Privalov, and A. I. Reshetnikov

Quantitative estimation of methane emissions in St. Petersburg and its environs is carried out by processing observations at Voeikovo station. The approach is based on the formulation and regularized solution of an inverse problem of the theory of pollution transport in the atmosphere. The effect of the methane buildup in the atmospheric mixed layer at night under conditions of temperature inversions is considered. The resulting emission field is inhomogeneous. Mean values of the methane flux density on the territory of settlements and farmlands between Voeikovo and the city border are 0.22 (1 ± 20%) g CH4 /(km2 ∙ s) (random root-mean square errors of estimates are given in the parentheses) . In the urban area, including the main part of the city and a southern suburban zone with towns which are St. Petersburg municipal districts, they are 0.95 (1 ± 20%) g CH4/(km2 ∙ s). The total methane emission from the urban area is estimated to be 63 (1 ± 30%) kt/year. The estimates are obtained for nighttime conditions of a non-heating season, for low cold distributed emissions. They do not take into account emissions from tall chimneys. The estimates obtained are compared with results of other authors.