Presentation given at CARIBIC workshop at Lufthansa Training & Conference Center Seeheim (Germany), October 2011. This material is now online as a discussion paper in ACPD, that can be found on http://www.atmos-chem-phys-discuss.net/12/589/2012/acpd-12-589-2012.html

1. “ CARIBIC based D/H measurements for understanding the molecular hydrogen (H 2 ) cycle” by Anneke M. Batenburg et al. is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Please include a proper attribution when using this work. The material that was presented in this presentation was later published in a discussion paper in ACPD, that can be found on: http://www.atmos-chem-phys-discuss.net/12/589/2012/acpd-12-589-2012.html

2. CARIBIC based D/H measurements for understanding the molecular hydrogen (H 2 ) cycle A.M. Batenburg , T.J. Schuck, A.K. Baker, A. Zahn, C.A.M. Brenninkmeijer, T. R öckmann

4. The atmospheric H 2 budget

5. Effects of a Hydrogen Economy

6. Isotope δ -notation The δ (D,H 2 ) value represents the deuterium-to-hydrogen ratio in the H 2 relative to a standard (Vienna Standard Mean Ocean Water (VSMOW))

7. Isotopic source signatures Isotopes can be used to gain information about different sources and sinks.

8. The EUROHYDROS network Batenburg et al., 2011 http://www.atmos-chem-phys.net/11/6985/2011/acp-11-6985-2011.html

9. EUROHYDROS data

11. Results: a first look

12. A first look: Caracas flights

15. Stratospheric H 2 cycle CH 4 H 2 H 2 O Source: Hydrocarbon oxidation Enriched in D Sink: Oxidation by OH Preferentially removes H Result of stratospheric processing: H 2 mixing ratio changes little, while δD increases dramatically.

16. Stratospheric input Pieterse et al., 2011 http://www.atmos-chem-phys.net/11/7001/2011/acp-11-7001-2011.html

17. Stratospheric samples Vertical gradient in δD(H 2 ), but not in mixing ratio

18. Stratospheric samples δD(H 2 ) `mirrors’ methane

19. Stratospheric correlations

20. Comparison to previous work

22. Summer monsoon GHG data Enhanced mixing ratios of Greenhouse gases occur in from May until September, with a maximum in August. ( T.J. Schuck et al. 2010)

23. δD lowering in monsoon

24. Correlation with methane