Continuous observations of carbon dioxide at Mace Head, Ireland from 1995 to 1999 and its net European ecosystem exchange

A 5-yr record of continuous high-frequency carbon dioxide CO2 observations over the 1995–1999 period for the Mace Head Atmospheric Research Station has been examined to reveal a complex interplay between local- and regional-scale sources and sinks. During the winter months, an additional CO2 source, over and above fossil fuel combustion, is required to support the observed concentrations of CO2 in European regionally polluted air masses. During the summer months, an additional CO2 sink is required. Over the entire study period, the additional net European ecosystem exchange source–sink required is –0.36±0.4 Gtonne C yr−1.