An estimate of the terrestrial carbon budget of Russia using inventory based, eddy covariance and inversion methods

. We determine the carbon balance of Russia, including Ukraine, Belarus and Kazakhstan using inventory based, eddy covariance, Dynamic Global Vegetation Models (DGVM), and inversion methods. Our current best estimate of the net biosphere to atmosphere flux is −0.66 Pg C yr−1. This sink is primarily caused by forests that using two independent methods are estimated to take up −0.69 Pg C yr−1. Using inverse models yields an average net biopshere to atmosphere flux of the same value with a interannual variability of 35 % (1σ). The total estimated biosphere to atmosphere flux from eddy covariance observations over a limited number of sites amounts to −1 Pg C yr−1. Fires emit 137 to 121 Tg C yr−1 using two different methods. The interannual variability of fire emissions is large, up to a factor 0.5 to 3. Smaller fluxes to the ocean and inland lakes, trade are also accounted for. Our best estimate for the Russian net biosphere to atmosphere flux then amounts to −659 Tg C yr−1 as the average of the inverse models of −653 Tg C yr−1, bottom up −563 Tg C yr−1 and the independent landscape approach of −761 Tg C yr−1. These three methods agree well within their error bounds, so there is good consistency between bottom up and top down methods. The best estimate of the net land to atmosphere flux, including the fossil fuel emissions is −145 to −73 Tg C yr−1. Estimated methane emissions vary considerably with one inventory-based estimate providing a net land to atmosphere flux of 12.6 Tg C-CH4yr −1 and an independent model estimate for the boreal and Arctic zones of Eurasia of 27.6 Tg C-CH4 yr−1.