Natural tritium deposition over Antarctica and estimation of the mean global production rate

• Published in: Geophysical Research Letters
• Main Authors: Jouzel, Jean, Merlivat, Liliane, Mazaudier, D., Pourchet, M., Lorius, Claude
• Other Authors: Laboratoire de Biogéochimie Isotopique, Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1982
• Subjects: [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; Antarc*; Antarctic; Antarctica; South pole
• Online Access: https://hal.science/hal-03482813; https://hal.science/hal-03482813/document; https://hal.science/hal-03482813/file/undefined-7.pdf; https://doi.org/10.1029/GL009i010p01191

International audience Tritium content was measured in snow deposited in Antarctica before the first arrival of artificial tritium (1954), both at Dome C (74°39′S) and South Pole. The mean tritium values at the time of precipitation are equal to 32 ± 2 and 26 ± 3 TU at South Pole (1939-1942) and Dome C (1951) respectively. A seasonal pattern of natural tritium fallout identical to the artificial pattern (with a winter maximum) is observed in the South Pole profile.The deposition rate of natural tritium is 0.6 and 0.2 tritium atoms cm−2.sec−1 at South Pole and Dome C respectively. Its geographical variation over Antarctica appears quite similar to that existing for artificial tritium, clearly showing that the same mechanisms govern the deposition of natural and artificial tritium, in particular tritium injection over polar regions during Antarctic winter. A mean deposition rate of 0.37 tritium atoms cm−2.sec−1, over Antarctica is derived giving an estimated mean global production rate of 0.2 tritium atoms cm−2.sec−1.This strongly suggests that natural tritium results only from cosmic ray production.