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

[U03-P06] Spatiotemporal Variability of Local Marine Reservoir Correction in the North Western Pacific

*Yuning Zeng¹, Yusuke Yokoyama¹, Shoko Hirabayashi¹, Yosuke Miyairi¹, Atsushi Suzuki³, Takahiro AZE¹, Yuta Kawakubo² (1.Atmosphere and Ocean Research Institute, The 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:local marine reservoir correction, coral radiocarbon

The surface ocean exchanges with the atmosphere and the ¹⁴C-depleted deep ocean, and has a ¹⁴C level intermediate between these two reservoirs. This results in an apparent ¹⁴C age of surface ocean samples several hundred years older than contemporaneous terrestrial samples. Such an apparent age is defined as the radiocarbon marine reservoir age (R). As the R value of a given location may be different than the model R of the “global” surface ocean (a difference between ¹⁴C age of a marine calibration curve (e.g., Marine20) and that of a terrestrial calibration curve (e.g., IntCal20) at a given time), the ¹⁴C age offset between these two values is expressed as the regional marine reservoir correction (ΔR). ΔR values are strongly influenced by local oceanographic conditions, such as ocean currents, deep-water upwelling, and inflow of freshwater, therefore they were used for reconstructing ocean circulation. Here we report more than two hundreds ΔR data from a coral in Kikai Island covering 1580-1950 CE and discuss how its spatiotemporal distribution varies with changes in oceanographic and climatic conditions.