Regional sources and CH4 seasonal cycle in Central Siberia and Arctic: observations and numerical calculations
K.B. Moiseenko1, Yu.A. Shtabkin1, A.V. Vasileva1, A.I. Skorokhod1,2, E.I. Fedorova1
1A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences, Moscow, Russia
2Department of Meteorology and Geophysics, University of Vienna, Vienna, Austria
Keywords: methane, troposphere, Central Siberia, Arctic, regional CH sources, WetCHARTs, EDGAR, ТХМ GEOS-Chem, atmospheric transport
Abstract
Contribution of anthropogenic and wetland methane emissions in North Eurasia (> 40°N) and Russia into the near-surface CH4 abundance at ZOTTO, Teriberka, and Tixi measurement sites is quantified using GEOS-chem global chemical-transport model. Numerical results agree well with the proposed semi-analytical solution, in which the total response in the CH4 level at a given site is represented as the sum of direct (synoptic) and global terms. The annual average direct contribution of Russian anthropogenic emissions into CH4 mixing ratio measured at ZOTTO (38.6 ppbv) is twice as large as that for Western Europe sources (17.7 ppbv). For the Arctic sites, the anthropogenic input from Russian and European anthropogenic sources is roughly similar (19.5 ppbv and 12.4 ppbv, correspondingly). The input from continental sources into methane abundance and its annual variability at the Arctic sites are generally lower compared to those at the ZOTTO site due to larger transport times from upstream CH4 source regions. Atmospheric responses in methane levels at the Teriberca and Tixi sites to CH4 continental sources are found to be very close, which is explained by spatial homogenization of the anthropogenic and biogenic signals in high latitudes.
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