演題概要

2P-23（1A-O1-1415）

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北西太平洋における炭素14海洋リザーバー補正値の時空間変動

(¹東大大海研・ ²産総研)
^o曾宇宁¹・ 横山祐典¹・ 宮入陽介¹・ 平林頌子¹・ 鈴木淳²

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 regional oceanographic conditions, such as ocean currents, deep-water upwelling, and inflow of freshwater, therefore they were used for reconstructing ocean circulation. Here we report 244 ΔR data in Kikai Island during 1580-1950.