@article{fdi:42328,
  title = {{T}he age of the air in the firn and the ice at {S}ummit, {G}reenland},
  author = {{S}chwander, {J}. and {B}arnola, {J}.{M}. and {A}ndri{\'e}, {C}hantal and {L}euenberger, {M}. and {L}udin, {A}. and {R}aynaud, {D}. and {S}tauffer, {B}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n the framework of the {E}urocore drilling project 1989, at {S}ummit, {C}entral {G}reeland, air samples were collected from a drill hole in the firn at several depth levels. {T}he samples have been analyzed for 85{K}r, {CO}2, {CH}4, {CFC}'s ({F}-11 and {F}-12) contents and for the isotopic composition of nitrogen and oxygen. {T}he measured data are compared with the results of a diffusion model. {CO}2, for example takes 12 years (with a standard deviation of 7.5 years) to diffuse from the surface to the firn-ice transition under the present climatic conditions at {S}ummit. {T}he difference between the age of the ice and the mean age of the occluded air is approximately 210 years. {A}n enrichment of the heavier isotopes due to separation by gravity has been observed. {M}olecular diffusion alone suffices to explain the observed concentrations trends in the firn column. {W}e can, however, not exclude the existence of a convective zone below the surface. {W}e have also measured the density and closed porosity along the firn core that has been retrieved when drilling the hole. {T}he porosity data reveal that the air is occluded into bubbles mainly between 65 and 80 m, corresponding to densities of 790 and 830 kg/m3, respectively. ({R}{\'e}sum{\'e} d'auteur)},
  keywords = {{MESURE} ; {OXYGENE} ; {ISOTOPE} ; {AIR} ; {GLACE} ; {NITROGENE} ; {GROENLAND} ; {SUMMIT}},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch},
  volume = {98},
  numero = {{D}2},
  pages = {2831--2838},
  ISSN = {0148-0227},
  year = {1993},
  DOI = {10.1029/92{JD}02383},
  URL = {https://www.documentation.ird.fr/hor/fdi:42328},
}