“…3.5). At the moment, there is a serious gap in our knowledge on tropospheric composition and chemistry over Russia and China, with particularly few observation programs being active over Siberia (Crutzen et al, 1998;Ramonet et al, 2002;Paris et al, 2008;Kozlova et al, 2008;Uttal et al, 2015, Paris et al, 2010aSasakawa et al, 2010;Chi et al, 2013;Saeki et al, 2013;Ding et al, 2013a, b;Berchet et al, 2015;Heimann et al, 2014). There is thus an urgent need for harmonized, coordinated and comprehensive greenhouse gas, trace gas, and aerosol in situ observations over northern Eurasia and China (longterm transport aspect) comparable to European and circumpolar data observations.…”