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首页> 外文期刊>Journal of Physical Oceanography >On the Estimation of Deep Atlantic Ventilation from Fossil Radiocarbon Records. Part Ⅰ: Modern Reference Estimates
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On the Estimation of Deep Atlantic Ventilation from Fossil Radiocarbon Records. Part Ⅰ: Modern Reference Estimates

机译：论化石辐射碳记录深度大西洋通风的估计。 第Ⅰ部分：现代参考估计

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Radiocarbon dates of fossil carbonates sampled from sediment cores and the seafloor have been used to infer that deep ocean ventilation during the last ice age was different from today. In this first of two companion papers, the time-averaged abyssal circulation in the modern Atlantic is estimated by combining a hydrographic climatology, observational estimates of volume transports, Argo float velocities at 1000 m, radiocarbon data, and geostrophic dynamics. Different estimates of modern circulation, obtained from different prior assumptions about the abyssal flow and different errors in the geostrophic balance, are produced for use in a robust interpretation of fossil records in terms of deviations from the present-day flow, which is undertaken in Part II. We find that, for all estimates, the meridional transport integrated zonally and averaged over a hemisphere, (V_k), is southward between 1000 and 4000m in both hemispheres, northward between 4000 and 5000m in the South Atlantic, and insignificant between 4000 and 5000m in the North Atlantic. Estimates of (V_k) obtained from two distinct prior circulations-one based on a level of no motion at 4000 m and one based on Argo float velocities at 1000 m-become statistically indistinguishable when △~(14)C data are considered. The transport time scale, defined as T_t = V_k(V_t), where V_k is the volume of the kth layer, is estimated to about a century between 1000 and 3000 m in both the South and North Atlantic, 124 ± 9yr (203 ± 23 yr) between 3000 and 4000 m in the South (North) Atlantic, and 269 ± 115 yr between 4000 and 5000 m in the South Atlantic.
机译：从沉积物核心和海底采样的化石碳酸碳酸盐的无线电碳日期已被用来推断最后一次冰河时代的深海通风与今天不同。在两个伴随论文中的第一个，通过组合水文气候学，体积运输观测估计，在1000米，无线电金数据和地球节动力学动力学中的植物浮子速度，估计现代大西洋中的时间平均深度循环。从关于深海流动的不同现有假设获得的现代循环的不同估计，生产用于从本日流量的偏差方面的强大解释化石记录，这部分是部分II。我们发现，对于所有估计，对齐地进行了间距并在半球（V_K）上持平均的化学运输，在南大西洋的北方北部的1000到4000米之间，在4000到5000米之间，介于4000到5000米之间。北大西洋。基于在考虑△〜（14）C数据时，基于在4000μm和基于ARGO浮动速度的基于4000μm和一个基于ARGO浮动速度的情况下，从一个不同的先前循环获得的估计值。定义为t_t = v_k（v_t）的传输时间尺度，其中v_k是kth层的音量，估计到南部和北大西洋的1000至3000米之间的大约一个世纪，124±9yr（203±23南部（北）大西洋南部（北）3000至4000米之间，南大西洋介于3009±115米之间。

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