Quantification of carbon dioxide, methane, nitrous oxide, and chloroform emissions from atmospheric observations at Mace Head and Radon efflux measurement over Ireland.

Biraud S., Ielsch G. Fall Meeting of the American Geophysical Union (AGU), San-Francisco Ca., USA, 10-14 December 2001.

Flux estimates of CO2, CH4, N2O, and CHCl3 over Ireland are inferred from continuous atmospheric records of these species. We use radon-222 (222Rn) as a reference compound to estimate unknown sources of other species. In order to better quantify 222Rn exhalation from the soil and its seasonal variability, two field campaigns have been conducted during wintertime (October 2000) and summertime (July 2001). The correlation between each species and 222Rn is calculated for a suite of diurnal events that have been selected in the Mace Head record over the period 1995-1997 to represent air masses exposed to sources over Ireland. We established data selection based on criteria using 222Rn and 212Pb thresholds. We estimated flux densities of 12-15 103 kg CH4 km-2 yr-1, 680-830 kg N2O km-2 yr-1, and 20-30 kg CHCl3 km-2 yr-1 for CH4, N2O, and CHCl3, respectively. We also inferred flux densities of 250-310 103 kg C km-2 yr-1 for CO2 during wintertime, of 760-950 103 kg C km-2 yr-1 for CO2 during summer nighttime.