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CRYOSTAT Résumé de rapport

Project ID: EVK2-CT-2001-00116
Financé au titre de: FP5-EESD
Pays: Switzerland

Measurements of isotope ratios and elemental ratios of permanent gases in NGRIP firn air

Mass spectrometric analyses of permanent gas elemental and isotope ratios will be made on firn air and ice from drilling campaigns, and firn air from year-round studies, including the following:
Elemental ratios: O2/N2, Ar/N2, Ar/O2, Ne/Ar, Kr/Ar, Xe/Ar
Isotope ratios: d15N(N2), d17O(O2), d18O(O2), d36Ar, isotopes of Ne, Kr, Xe
Radioactive gases: 85Kr

Deviations from fractionation due to gravitational separation will be examined near the snow surface and at the firn-ice transition. In the former mixing and separation is controlled by convective airflows and thermal diffusion. In the latter fractionation may occur by non-laminar gas flows through microporous structures, close off of firn pores or by firn pumping. Meteorological and physical parameters in conjunction with trace gas profiles will be the basis for quantifying gas mixing in the upper firn strata. Overlapping analysis of firn air and ice within and below the firn-ice transition will allow studies of possible fractionation processes there. These processes will be incorporated in to the firn diffusion models.


Jakob SCHWANDER, (Senior scientist)
Tél.: +41-31-6314476
Fax: +41-31-6318742