The age of iron and iron source attribution in the ocean
The age of iron and iron source attribution in the ocean
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DOI：
10.1002/2016gb005418
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发表时间：
2016-10-01
影响因子：
5.2
通讯作者：
Pasquier, Benoit
中科院分区：
文献类型：
--
作者：
Holzer, Mark;Frants, Marina;Pasquier, Benoit
我们使用示踪剂分区溶解铁（dFe）的贡献，从每个来源内的铁循环的数值模型，而不扰动系统。这些贡献根据注入海洋以来的时间进一步划分，这定义了它们的铁龄谱和平均铁龄。这些诊断的效用示出了一个家庭的逆模型估计的铁循环，约束的数据同化的流通和可用的dFe测量。源的贡献进行了比较与源异常定义为解决方案之间的差异和没有源的问题。我们发现，在南大洋真光区，热液和沉积物的贡献范围从15%到30%的总的每一个，异常低估了一个类似于2的因素，因为清除的非线性。铁的年龄只有重置清除，并达到几百年的平均值在南大洋透光带，揭示风成铁有主要是从深度再生dFe。根据源区和路径标记铁表明，70-80%的风成dFe在南极附近的真光层来自46 ° S以北的路径，达到不到1公里的深度。热液铁具有最古老的表面平均年龄的顺序中层通风时间。不确定性的措施是由我们的诊断在家庭的铁循环估计，其中每个成员有不同的风源强度的系统变化。
We use tracers to partition dissolved iron (dFe) into the contributions from each source within a numerical model of the iron cycle without perturbing the system. These contributions are further partitioned according to the time since injection into the ocean, which defines their iron-age spectrum and mean iron age. The utility of these diagnostics is illustrated for a family of inverse model estimates of the iron cycle, constrained by a data-assimilated circulation and available dFe measurements. The source contributions are compared with source anomalies defined as the differences between solutions with and without the source in question. We find that in the Southern Ocean euphotic zone, the hydrothermal and sediment contributions range from 15% to 30% of the total each, which the anomalies underestimate by a factor of similar to 2 because of the nonlinearity of scavenging. The iron age is only reset by scavenging and attains a mean of several hundred years in the Southern Ocean euphotic zone, revealing that aeolian iron there is supplied primarily from depth as regenerated dFe. Tagging iron according to source region and pathways shows that 70-80% of the aeolian dFe in the euphotic zone near Antarctica is supplied from north of 46 degrees S via paths that reach below 1 km depth. Hydrothermal iron has the oldest surface mean ages on the order of middepth ventilation times. A measure of uncertainty is provided by the systematic variations of our diagnostics across the family of iron cycle estimates, each member of which has a different aeolian source strength.