1. Significant changes in observed CO 2 and O 2 online records at Jungfraujoch station C.Uglietti, M. Leuenberger, F.L.Valentino Climate and Environmental Physics, Physics Institute, University of Bern 5 th CarboEurope-IP Meeting, Poznan, Poland, 7-12 October, 2007

2. Sampling site: Jungfraujoch Switzerland 46°33’N, 7°59’O 3580m a.s.l. Jungfraujoch Descret Sampling: 2 flasks samples every week, 1L glass flasks, sampling time: 06.30-07.30 Continuous Sampling: CO 2 and O 2 measured with different devices

4. Jungfraujoch on-line and flasks data trends O 2 /N 2 = -33 per meg/yr CO 2 = 1.61 ppm/yr CO 2 = 1.88 ppm/yr on-line trend line flasks trend line O 2 /N 2 = -22 per meg/yr on-line trend line flasks trend line

5. How are trends calculated? O 2 /N 2 = -33 per meg/yr CO 2 = 1.61 ppm/yr CO 2 = 1.88 ppm/yr on-line trend line flasks trend line O 2 /N 2 = -22 per meg/yr on-line trend line flasks trend line Trends and harmonics not correctly deseasonalized (2005-2007.7) Trends and harmonics after Nakazawa (2005 – 2007) O 2 /N 2 = -45 per meg/yrCO 2 = 2.4 ppm/yr flasks trend line Trends are dependent on the period considered

6. Comments and conclusions:  The agreement between flasks and on line data is good for CO 2 and moderate for O 2. Continuous data reveal additional short-term variations suggesting to reconsider our restrictive outlier criteria for the flasks measurements. The continuous measurements can be used to better validate the flask data and vice versa.  Continuous measurements give us more reliable information on short term variations (diurnal or weekly variations). Of particular interest is the influence of diurnal and seasonal signal strength to trend estimations.  Trend analysis is quite complicated because results do depend on spline tools used.

7. Thanks for your attention!

8. CO 2 comparison with selected online values