Browsing by Autor "Emiko Inui"

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    Latest <sup>14</sup>C Concentrations of Plant Leaves at High Altitudes in the Northern and Southern Hemispheres: Vertical Stability of Local Suess Effect
    (Cambridge University Press, 2013) Hirohisa Sakurai; Fuyuki Tokanai; Kazuhiro Kato; Yui Takahashi; Taichi Sato; Satoshi Kikuchi; Emiko Inui; Yumi Arai; Kimiaki Masuda; Hiroko Miyahara
    The radiocarbon concentrations in plant leaves from different altitudes at 3 sampling locations were measured with the new compact accelerator mass spectrometer (AMS) at Yamagata University to investigate air mixing on a global scale. The sampling locations are Yamagata in the mid-latitudes of the Northern Hemisphere (NH), Kenya in the equatorial region (EQ), and Chacaltaya in the Southern Hemisphere (SH). The 14 C concentrations of the plant leaves ranged from 102 to 105 pMC. The 14 C concentrations at high altitudes and mountain summits showed similar values of 104.2 ± 0.28, 104.3 ± 0.36, and 104.4 ± 0.23 pMC at the Yamagata, Kenya, and Chacaltaya sites, respectively. These results indicate that air from the free troposphere is well mixed on a global scale. The local Suess effect was calculated using the 14 C concentrations of leaves at the land surface and mountain summits. The fractions were estimated as 1.25 ± 0.3% and 0.87 ± 0.44% at Yamagata and Nairobi, respectively. This estimation method is more advantageous than the conventional calculation. The life cycle of the leaves sampled is 1 or 2 yr, and hence the leaves allow us to study the 14 C concentrations in the ambient atmosphere during a narrow and specific time period.