Measurements and trend analysis of O sub(2), CO sub(2) and d super(1) super(3)C of CO sub(2) from the high altitude research station Junfgraujoch, Switzerland - A comparison with the observations from the remote site Puy de Dome, France

Atmospheric O sub(2) and CO sub(2) flask measurements from the high altitude research station Jungfraujoch, Switzerland, and from the observatory at Puy de Dome, France, are presented. Additionally, the Jungfraujoch d super(1) super(3)C record of CO sub(2) is discussed. The observations on flask samples collected at the Jungfraujoch station show, since 2003, an enhancement of the oxygen trend which amounts to about 45 per meg/year with a corresponding CO sub(2) increase of around 2.4 ppm/year. This enhancement is comparable with that observed at the Puy de Dome station where oxygen, since mid 2002, has decreased with a rate of about 50 per meg/year whilst the CO sub(2) increase was of around 1.7 ppm/year but exhibiting a higher variability. Several processes influence dO sub(2)/N sub(2). However, these processes are marked with different oxidation ratios (O sub(2):CO sub(2)) that can be used to distinguish them. The apparent slopes calculated from correlation plots between de-trended CO sub(2) and dO sub(2)/N sub(2) records as well as between corresponding trends are significantly larger than the observed terrestrial exchange and fossil fuel emission slopes indicating a strong oceanic influence. Since ocean-atmosphere exchange can have very variable O sub(2):CO sub(2) ratios depending on processes within the ocean, it is to our understanding the only possibility to explain our observations. The stability of the dO sub(2)/N sub(2) scale is critical in this regard, therefore, it is addressed here and we found no significant scale drift which would influence our trend calculations. In our view more important are criterions on the data selection before trend analysis.