1. GEOF236 CHEMICAL OCEANOGRAPHY (HØST 2012) Christoph Heinze University of Bergen, Geophysical Institute and Bjerknes Centre for Climate Research Prof. in Global Carbon Cycle Modelling Allegaten 70, N-5007 Bergen, Norway Phone: +47 55 58 98 44 Fax: +47 55 58 98 83 Mobile phone: +47 975 57 119 Email: christoph.heinze@gfi.uib.nochristoph.heinze@gfi.uib.no DEAR STUDENT AND COLLEAGUE: ”This presentation is for teaching/learning purposes only. Do not use any material of this presentation for any purpose outside course GEOF236, ”Chemical Oceanography”, autumn 2012, University of Bergen. Thank you for your attention.”

2. Sarmiento&Gruber 2006 Chapter 3: Air-sea interface, part 2

3. Surface CO 2 air-sea flux climatology, Takahashi et al., 2009 Sea-air CO 2 flux February August

4. Central issue in this chapter: What controls the air-sea flux / sea-air flux of different gases? How can this flux be quantified (or predicted)? Conceptual model Flux Φ of gas across water air interface: Φ = transfer velocity ∙ concentration gradient What is the transfer velocity and on what does it depend? How to determine the concentration gradient?

5. Solubility – ideal/non-ideal gases: Black board Sarmiento & Gruber (2006)

6. Solubilities of gases and sea water temperature: Sarmiento & Gruber (2006)

7. Broecker, W.S., and T.-H. Peng, 1982, Tracers in the Sea, ELDIGIO Press, Palisades NY, 690 pp. Solubility of gases and the sea water temperature CO 2

8. Solubilities of gases and salinity: Weiss, Mar.Chem., 1974 Solubility coefficients for CO 2

9. Ideal gases Source: Inorganic chemistry textbook by Christen, 1982 Ideal up to about 1%, for p less or equal 1 atm and T over 0 deg C pressure volume

10. Zeebe & Wolf-Gladrow 2001

11. The stagnant film model of air-sea gas exchange: Sarmiento & Gruber (2006)

12. Jähne and Hauβecker, Annu. Rev. Fluid Mech. 1998 Flux: j c = k (C s -C b ) =D/z (C s -C b ) D= Sc/ ν Sc= ν /D Schmidt number D: diffusion coefficient for concentration ν: diffusion coefficient for momentum (kinematic viscosity) The stagnant film model of air-sea gas exchange: Index s for surface, index b for bulk For Ostwaldt solubility α=3

13. Stagnant film model: Black board Sarmiento & Gruber (2006)

14. Overview gases and resistances in water and air phases: Jähne and Hauβecker, Annu. Rev. Fluid Mech. 1998

15. Overview - stagnant film model, film replacement model, boundary layer model: Stagnant film model: 1/k ~ Sc 1 Micrometeorological boundary layer model (turbulence theory, Deacon, 1977): 1/k ~ Sc 2/3 Film replacement model: 1/k ~ Sc 1/2

16. Gas transfer velocity versus wind speed (for a gas with Sc≈600). Liss, P., and L. Merlivat, 1986, Air-Sea gas exchange rates: Introduction and synthesis, in: The role of air-sea exchange in geochemical cycling, P. Buat-Ménard, editor, Dordrecht, Holland, 113- 127.

17. Source: Sarmiento&Gruber 2006