The concentration of radiocarbon (14C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their14C in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-average marine record of radiocarbon from 0–55 cal kBP and serves as a baseline for regional oceanic variation. Marine20 is intended for calibration of marine radiocarbon samples from non-polar regions; it is not suitable for calibration in polar regions where variability in sea ice extent, ocean upwelling and air-sea gas exchange may have caused larger changes to concentrations of marine radiocarbon. The Marine20 curve is based upon 500 simulations with an ocean/atmosphere/biosphere box-model of the global carbon cycle that has been forced by posterior realizations of our Northern Hemispheric atmospheric IntCal2014C curve and reconstructed changes in CO2obtained from ice core data. These forcings enable us to incorporate carbon cycle dynamics and temporal changes in the atmospheric14C level. The box-model simulations of the global-average marine radiocarbon reservoir age are similar to those of a more complex three-dimensional ocean general circulation model. However, simplicity and speed of the box model allow us to use a Monte Carlo approach to rigorously propagate the uncertainty in both the historic concentration of atmospheric14C and other key parameters of the carbon cycle through to our final Marine20 calibration curve. This robust propagation of uncertainty is fundamental to providing reliable precision for the radiocarbon age calibration of marine based samples. We make a first step towards deconvolving the contributions of different processes to the total uncertainty; discuss the main differences of Marine20 from the previous age calibration curve Marine13; and identify the limitations of our approach together with key areas for further work. The updated values forΔR, the regional marine radiocarbon reservoir age corrections required to calibrate against Marine20, can be found at the data basehttp://calib.org/marine/.

中文翻译：

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Marine20—海洋放射性碳年龄校准曲线 (0–55,000 cal BP)

放射性碳浓度 (14C）在海洋和大气之间有所不同。从获得它们的样品中进行放射性碳测定14因此，海洋环境中的 C 需要一个特定于海洋的校准曲线，并且不能直接针对基于大气的 IntCal20 曲线进行校准。本文介绍了 Marine20，这是对国际公认的海洋放射性碳年龄校准曲线的更新，它提供了 0-55 cal kBP 的非极地全球平均海洋放射性碳记录，并作为区域海洋变化的基线。Marine20 旨在校准来自非极地地区的海洋放射性碳样品；它不适合在海冰范围、海洋上升流和海气交换可能导致海洋放射性碳浓度发生较大变化的极地地区进行校准。14C曲线和重建的CO变化2从冰芯数据中获得。这些强迫使我们能够将碳循环动力学和大气中的时间变化结合起来14C级。全球平均海洋放射性碳储层年龄的箱模型模拟类似于更复杂的三维海洋环流模型。然而，箱模型的简单性和速度使我们能够使用蒙特卡罗方法来严格传播历史大气浓度的不确定性14C 和碳循环的其他关键参数一直到我们最终的 Marine20 校准曲线。这种不确定性的稳健传播对于为海洋样品的放射性碳年龄校准提供可靠的精度至关重要。我们朝着去卷积不同过程对总不确定性的贡献迈出了第一步；讨论 Marine20 与之前的年龄校准曲线 Marine13 的主要区别；并确定我们方法的局限性以及进一步工作的关键领域。的更新值ΔR，可以在数据库中找到针对 Marine20 进行校准所需的区域海洋放射性碳储层年龄校正http://calib.org/marine/.