Physical-biological interactions in North Pacific oxygen variability
Physical-biological interactions in North Pacific oxygen variability
复制标题
北太平洋氧气变化的物理-生物相互作用
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
L. Thompson
中科院分区：
文献类型：
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作者：
C. Deutsch;S. Emerson;L. Thompson
[1]我们调查的时间变化的氧气在北太平洋上层水柱使用后报海洋模式。该模型嵌入简单的营养物质和O2的地球化学循环内的等密度环流模型，被迫在表面的历史大气条件。由此产生的O2的变化是空间和时间复杂的，但包括大规模的O2减少之间的20世纪80年代和90年代在副极地地区，同时O2在副热带地区增加。这些模拟的变化与沿沿着重复样带观察到的变化模式相似（Emerson等人，2004年），这表明该模型捕捉到了世纪后期北太平洋O2变化的关键机制。进行了额外的模拟，以区分由于生物学、通气和循环的变异性而导致的O2变化。出口生产的区域趋势推动了重要的氧气变化，这些变化集中在温跃层上部，那里的海水化率最大。然而，浅的生物O2变化往往是平衡的反对物理驱动的O2变化。相比之下，物理过程的通风和流通被发现是模式O2的变化在较低的通风温跃层，观察到的O2异常是最大的主要原因。这些结果表明，在较低的通风温跃层的O2的变化可能是一个有用的示踪剂的物理气候变化在北太平洋，而在生物泵的变化可能难以检测的基础上O2的趋势。继续分析地下O2变化的历史模式将为这些结论提供重要的进一步检验。
[1] We investigate the temporal variability of oxygen in the upper water column of the North Pacific using a hindcast ocean model. The model embeds simple biogeochemical cycles of nutrients and O2 within an isopycnal circulation model that is forced at the surface by historical atmospheric conditions. The resulting O2 variability is spatially and temporally complex, but includes large-scale O2 decreases between the 1980s and 1990s in the subpolar region, and simultaneous O2 increases in the subtropics. These simulated changes are similar in pattern to those observed along repeat transects (Emerson et al., 2004), suggesting that the model captures key mechanisms of late twentieth century O2 variability in the North Pacific. Additional simulations were performed to distinguish O2 changes due to variability in biology, ventilation, and circulation. Regional trends in export production drive significant oxygen changes that are focused in the upper thermocline, where remineralization rates are largest. However, shallow biological O2 changes are often balanced by opposing physically driven O2 changes. In contrast, physical processes of ventilation and circulation are found to be the dominant cause of model O2 variability in the lower ventilated thermocline, where observed O2 anomalies are the largest. These results suggest that O2 variability in the lower ventilated thermocline may be a useful tracer of physical climate change in the North Pacific, while changes in the biological pump may be difficult to detect on the basis of O2 trends alone. Continued analysis of historical patterns of subsurface O2 variability will provide important further tests of these conclusions.