Interannual variability of atmospheric CO₂ concentrations over central Siberia from ZOTTO data for 2009–2015

The interannual variations in the characteristics of the seasonal cycle (annual and seasonal amplitudes, winter emission, dates of annual minimum and maximum, and phase) and in the growth rate of atmospheric carbon dioxide concentration over Central Siberia are analyzed for the period from May 2009 to January 2016. The results are based on the continuous monitoring of CO2 concentration at the Zotino Tall Tower Observatory (ZOTTO, www.zottoproject.org). It is found that the seasonal amplitude of CO2 concentration in the atmo spheric surface layer over Western Siberia is 26.4 ± 0.8 μmol/mol (no long-term trend toward its increase was revealed), the annual mean growth rate of CO2 is 2.34 μmol/mol per year, its variations range from 1 to 4 μmol/mol per year