[U-03] Advanced understanding of Quaternary and Anthropocene hydroclimate changes in East Asia

[U03-P12] Radiocarbon Variability Recorded in Coral from Kikai Island to Understand Oceanography in the North Western Pacific Region

*Yuning Zeng¹, Yusuke Yokoyama¹, Shoko Hirabayashi¹, Yosuke Miyairi¹, Atsushi Suzuki³, Takahiro AZE¹, Yuta Kawakubo² (1.Atmosphere and Ocean Research Institute, Graduate School of Arts and Sciences, University of Tokyo, 2.Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 3.Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST))

Keywords:coral radiocarbon, Kuroshio Current, Ryukyu Current

Radiocarbon (¹⁴C) in corals can be used as a sensitive indicator of vertical and horizontal advection of water masses, which contributes to the understanding of ocean circulation. In this study, a high-resolution ¹⁴C record spanning 1947-2009 was obtained from a coral in Kikai Island in the south of Japan. The overall trend of Kikai ¹⁴C curve is consistent with those in previous studies with an early bomb-¹⁴C spike in July 1955, a rapid increase after 1962 and a steady decrease after 1980. The lack of periodicity in Kikai ¹⁴C reveals the complex oceanographic situation around Kikai. The ¹⁴C comparative study of Kikai and Ishigaki shows that the transport of ocean currents in this region is affected by PDO and ENSO. The Kikai ¹⁴C record show the potential of reconstructing local oceanography and improve the understanding of Kuroshio Current and Ryukyu Current.