HR: 0800h
AN: PP31B-1521    [Abstracts]
TI: Missing pieces in our understanding of 231Pa / 230Th fractionation in the ocean as revealed by modelling efforts
AU: * Siddall, M
EM: siddall@climate.unibe.ch
AF: Climate and Environmental Physics, Physics Institute, University of Bern, Climate and Environmental Physics Physics Institute Sidlerstrasse 5 Switzerland, Bern, BE CH3012 Switzerland
AU: Henderson, G M
EM: Gideon.Henderson@earth.ox.ac.uk
AF: Department of Earth Sciences, Oxford University, Parks Road, Oxford, OX1 3PR United Kingdom
AU: Edwards, N R
EM: n.r.edwards@open.ac.uk
AF: Earth Sciences Open University, Walton Hall, Milton Keynes, MK7 6AA United Kingdom
AU: Frank, M
EM: frank@erdw.ethz.ch
AF: IFM-GEOMAR, Leibniz Institute for Marine Sciences, University of Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany, Kiel, 24148 Germany
AU: Mller, S A
EM: smueller@climate.unibe.ch
AF: Climate and Environmental Physics, Physics Institute, University of Bern, Climate and Environmental Physics Physics Institute Sidlerstrasse 5 Switzerland, Bern, BE CH3012 Switzerland
AU: Stocker, T F
EM: stocker@climate.unibe.ch
AF: Climate and Environmental Physics, Physics Institute, University of Bern, Climate and Environmental Physics Physics Institute Sidlerstrasse 5 Switzerland, Bern, BE CH3012 Switzerland
AU: Joos, F
EM: joos@climate.unibe.ch
AF: Climate and Environmental Physics, Physics Institute, University of Bern, Climate and Environmental Physics Physics Institute Sidlerstrasse 5 Switzerland, Bern, BE CH3012 Switzerland
AB: We combine particle fields (dust, opal, CaCO3, POC) derived from observations with the Bern3D intermediate complexity ocean model and an equilibrium-scavenging model for isotopes. The equilibrium partition coefficient for particulate versus dissolved isotope activity is varied with particle type. The model can explain many of the features of the global 231Pa and 230Th distribution. The success of such a simple model at representing the global pattern of 231Pa / 230Th activity ratio supports the use of this proxy in paleoceanographic studies. Modelling reveals that 231Pa / 230Th fractionation by both dust and POM is poorly understood - an attempt is made to estimate these effects.
UR: http://www.climate.unibe.ch/~siddall/marksiddallprofessional.html
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4924 Geochemical tracers
DE: 4928 Global climate models (1626, 3337)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005