A detailed 2-year record of atmospheric 14CO in the temperate northern hemisphere

This paper presents a 2-year record (from September 1996 to July 1998) of atmospheric (CO)-C-14 measurements on whole air samples taken at the Mt. Sonnblick observatory (3106 m), a remote high-altitude site in Central Europe. An overall measurement precision of ca. 1/4 molecule (CO)-C-14 per cm(3) air has been achieved. A few events including unexpectedly low CO and (CO)-C-14 values in winter 1996/97 will be discussed in some detail incorporating stable isotope information. Since the amount of (CO)-C-14 data available for the Northern Hemisphere (NW) is rather sparse, this most detailed long-term (CO)-C-14 record for NH temperate latitudes may be a valuable contribution to the assessment of global atmospheric OH concentrations. (C) 2000 Elsevier Science B.V. All rights reserved.