THE PREINDUSTRIAL ATMOSPHERIC (CO2)-C-14 LATITUDINAL GRADIENT AS RELATED TO EXCHANGES AMONG ATMOSPHERIC, OCEANIC, AND TERRESTRIAL RESERVOIRS
THE PREINDUSTRIAL ATMOSPHERIC (CO2)-C-14 LATITUDINAL GRADIENT AS RELATED TO EXCHANGES AMONG ATMOSPHERIC, OCEANIC, AND TERRESTRIAL RESERVOIRS
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DOI：
10.1029/95gb01725
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发表时间：
1995-12-01
影响因子：
5.2
通讯作者：
STUIVER, M
中科院分区：
文献类型：
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作者：
BRAZIUNAS, TF;FUNG, IY;STUIVER, M
一个三维全球示踪剂输送模式（源自大气环流模式）模拟了大气中Delta（14）C随海洋边界条件的地理变化。区域大气-海洋（CO2）-C14通量受区域风相关气体交换系数（E）、海气pCO（2）差异（Delta pCO（2））和海洋C14/C12不足的控制。我们发现，从这些海气变量的合理集合重建的各种工业化前海洋情景都产生大气Delta（14）CO（2）的模式纬度梯度。（“NS Delta（14）C”）显著高于工业化前测量的NS Delta（14）C的+4.4 +/- 0.5千分之一（北纬45度到南纬45度），根据世纪前的树木年轮估计。NS Delta（14）C对区域Delta pCO（2）不敏感，但强烈依赖于南方高纬度（>50 ° S）的表层海洋Delta（14）C和E的选定值。海冰范围和高纬度风速的同时季节性可能部分解释了模拟和测量的工业化前NS Delta（14）C之间的差异。周转时间较长的陆地C-14汇（如泥炭地）也可能有助于减少NS Delta（14）C。根据我们对工业化前海洋表层三角洲（14）C、三角洲pCO（2）和其他地区E值的最佳估计，我们找到了一个“最适合”的海洋情景，其中工业化前南部海洋表层三角洲（14）C为-95 +/- 10 ‰，其pCO（2）为0 +/- 20 ppmv，其E值为0.088 ± 0.010 M m（-2）yr（-1）mu atm（-1）（比普遍接受的值0.110降低约20%）。工业化前海洋C-14净吸收量的独立估计值为+6.5 +/-0.5千克/年（-1），这是对全球平均值和南极E.
A three-dimensional global tracer transport model (derived from a general circulation model) simulates geographic variations in atmospheric Delta(14)C in response to oceanic boundary conditions. Regional atmosphere-ocean (CO2)-C-14 fluxes are controlled by regional wind-dependent gas exchange coefficients (E), air-sea pCO(2) differences (Delta pCO(2)) and oceanic C-14/C-12 deficiencies. We find that various preindustrial oceanic scenarios reconstructed from reasonable sets of such air-sea variables all produce model latitudinal gradients in atmospheric Delta(14)CO(2) (the ''NS Delta(14)C'') significantly greater than the measured preindustrial NS Delta(14)C Of +4.4 +/- 0.5 parts per thousand (45 degrees N to 45 degrees S), as estimated from pre-twentieth century tree rings. The NS Delta(14)C is insensitive to regional Delta pCO(2) but is strongly contingent on the chosen values for surface ocean Delta(14)C and E of southern high latitudes (>50 degrees S). The simultaneous seasonality in sea ice extent and high-latitude wind speeds may in part explain the discrepancy between modeled and measured preindustrial NS Delta(14)C. Terrestrial C-14 sinks with longer turnover times (such as peatlands) also potentially may help to reduce the NS Delta(14)C. With our best estimates for preindustrial surface ocean Delta(14)C, Delta pCO(2), and E values for other regions, we find a ''best fit'' ocean scenario in which the preindustrial southern surface ocean Delta(14)C is -95 +/- 10 parts per thousand, its pCO(2) is O +/- 20 ppmv, and its E is 0.088 +/- 0.010 M m(-2) yr(-1) mu atm(-1) (about 20% reduced from the widely accepted value of 0.110). An independent estimate of +6.5 +/- 0.5 kg yr(-1) for the net preindustrial oceanic C-14 uptake is an important constraint on global mean and Antarctic E.