Evaluating effect of ballast mineral on deep‐ocean nutrient concentration by using an ocean general circulation model
Evaluating effect of ballast mineral on deep‐ocean nutrient concentration by using an ocean general circulation model
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DOI：
10.1029/2007gb003067
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发表时间：
2008-09
影响因子：
5.2
通讯作者：
A. Oka;Seiya Kato;H. Hasumi
中科院分区：
文献类型：
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作者：
A. Oka;Seiya Kato;H. Hasumi
压载水参数化将沉水有机通量分为两部分：与压载矿物相关的通量和与矿物无关的通量。压载参数化开始被纳入全球海洋生态地球化学模式。然而，在这种参数化中使用的参数，如碳酸钙通量的参数没有足够的约束，并且难以定量评估压载引起的通量对深海营养盐浓度的影响程度。在这项研究中，我们通过使用卫星观测估计的出口产量和最先进的海洋环流模型模拟的海洋环流场进行64次敏感性模拟，获得碳酸钙通量的优化参数。通过比较有无压载通量和优化参数的模拟，估计太平洋深部6%的营养盐通过压载通量输送。由于这占总生物泵效应的30%，这表明生物泵将营养物质输送到深海的能力显著取决于压载诱导通量。额外的敏感性模拟的结果表明，与碳酸钙通量的模型参数的选择强烈影响其估计。虽然压载参数化的实施具有潜在的能力，以提高模拟的营养物浓度，这是可能的，只有当碳酸钙通量的模型参数被设置得适当。
The ballast parameterization separates sinking organic flux into two parts: the flux associated with ballast minerals and the flux independent of minerals. The ballast parameterization begins to be incorporated into global ocean biogeochemical models. However, parameters used in this parameterization such as those of calcium carbonate flux are not constrained enough and it has been difficult to evaluate quantitatively how much the ballast‐induced flux affects nutrient concentration in deep ocean. In this study, we obtain optimized parameters of calcium carbonate flux by conducting 64 sensitivity simulations using export production estimated from satellite observation and an ocean circulation field simulated by a state‐of‐the‐art ocean general circulation model. By comparing simulations with and without the ballast‐induced flux with the optimized parameters, 6% of nutrient of the deep Pacific is estimated to be transported by the ballast‐induced flux. Because this accounts for 30% of effects of the total biological pump, it indicates that the ability of the biological pump to carry nutrients to deep ocean significantly depends on the ballast‐induced flux. Results of additional sensitivity simulations suggest that choice of model parameters associated with calcium carbonate flux strongly affects its estimation. Although the implementation of the ballast parameterization has potential ability to improve simulation of nutrient concentration, it is possible only when the model parameters of calcium carbonate flux are set appropriately.