European greenhouse gas emissions estimated from continuous atmospheric measurements and radon 222 at mace head, ireland

Flux estimates of CO2, CH4 N2O, and CFCs over western Europe have been inferred from continuous atmospheric records of these species at the atmospheric research 771 station of Mace Head, Ireland. We use radon ( Rn) which has a fairly uniform source over continents as a reference compound to estimate unknown sources of other species. The Rn-222 is calculated for a suite of synoptic events that correlation between each species and have been selected in the Mace Head record over the period 1996/97. In the following, we describe the method and its uncertainties, and we establish data selection criteria that minimize the influence of local sources over Ireland, in the vicinity of the station, in order to select synoptic events originating from western Europe. We estimate western European flux densities of 45-30 10(3) kg C km(-2) month(-1) during wintertime for CO2, of 4.8-3.5 10(3) kg CH4 km(-2) yr(-1), 475-330 kg N2O km(-2) yr(-1) 2.5-1.8 kg CFC-11 km(-2) yr(-1) for CFC-11 and 4.2-2.9 kg CFC-12 km(-2) yr(-1) for CFC-12. Our estimates are independent, although in good agreement with those produced by inventories, except for CFC-11 where our estimate is much lower than the inventory