Observation-based estimates of fossil fuel-derived CO2 emissions in the Netherlands using Δ14C, CO and 222Radon

Surface emissions of CO2 from fossil fuel combustion (phi FFCO2) are estimated for the Netherlands for the period of May 2006-June 2009 using ambient atmospheric observations taken at station Lutjewad in the Netherlands (6 degrees 21'E, 53 degrees 24'N, 1 m. a.s.l.). Measurements of delta 14C on 2-weekly integrations of CO2 and CO mixing ratios are combined to construct a quasi-continuous proxy record (FFCO2*) from which surface fluxes (phi FFCO2*) are determined using the 222Rn flux method. The trajectories of the air masses are analysed to determine emissions, which are representative for the Netherlands. We compared our observationally based estimates to the national inventories and we evaluated our methodology using the regional atmospheric transport model REMO. Based on 3 yr of observations we find annual mean phi FFCO2* emissions of (4.7 +/- 1.6) kt km-2 a-1 which is in very good agreement with the Dutch inventories of (4.5 +/- 0.2) kt km-2 a-1 (average of 2006-2008).