Sensitivity analysis of simple global marine biogeochemical models
Sensitivity analysis of simple global marine biogeochemical models
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简单的全球海洋生物地球化学模型的敏感性分析
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发表时间：
2012
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通讯作者：
S. Khatiwala
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作者：
I. Kriest;A. Oschlies;S. Khatiwala
本研究展示了 46 项敏感性实验的结果，这些实验使用三个结构简单（分别为 2、3 和 6 个生物地球化学状态变量）的有机磷生产、输出和再矿化模型进行，并与全球海洋环流模型相结合，每个模型整合了 3000 年。模型的技能是通过相对于观察到的磷酸盐和氧气的全局分布的不同失配函数来评估的。在不同的模型中，发现观察到的磷酸盐和氧气分布的全局均方根失配对再矿化长度尺度的变化以及模拟初级生产的变化特别敏感。对于这个指标，溶解有机磷的产生和衰减以及浮游动物参数的变化不太重要。然而，对于解释上层海洋示踪剂失配的失配函数，生产参数和有机磷动态起着更大的作用。研究区域失配模式作为潜在模型缺陷的指标，例如缺少铁限制或下沉和再矿化长度尺度的缺陷。特别是，北太平洋北部和北大西洋北部的磷酸盐浓度之间的梯度主要由与颗粒通量相关的生物地球化学模型参数控制。对于这里进行的 46 项组合敏感性实验，观察到的氧和磷酸盐分布的全局失配表明，对于所采用的任一失配指标，与模拟的全球初级或出口产量没有明确的关系。然而，对于不同结构复杂性的不同模型，在氧和磷酸盐分布的模型数据与模拟中观和深海粒子通量的不匹配之间发现了一种相对紧密的关系，这种关系非常相似。对于模拟颗粒通量，获得了与观察到的示踪剂分布的最佳一致性，该通量与标称深度约为 1000 m 或更深的沉积物捕集器数据最接近。
This study presents results from 46 sensitivity experiments carried out with three structurally simple (2, 3, and 6 biogeochemical state variables, respectively) models of production, export and remineralization of organic phosphorus, coupled to a global ocean circulation model and integrated for 3000 years each. The models' skill is assessed via different misfit functions with respect to the observed global distributions of phosphate and oxygen. Across the different models, the global root‐mean square misfit with respect to observed phosphate and oxygen distributions is found to be particularly sensitive to changes in the remineralization length scale, and also to changes in simulated primary production. For this metric, changes in the production and decay of dissolved organic phosphorus as well as in zooplankton parameters are of lesser importance. For a misfit function accounting for the misfit of upper‐ocean tracers, however, production parameters and organic phosphorus dynamics play a larger role. Regional misfit patterns are investigated as indicators of potential model deficiencies, such as missing iron limitation, or deficiencies in the sinking and remineralization length scales. In particular, the gradient between phosphate concentrations in the northern North Pacific and the northern North Atlantic is controlled predominantly by the biogeochemical model parameters related to particle flux. For the combined 46 sensitivity experiments performed here, the global misfit to observed oxygen and phosphate distributions shows no clear relation to either simulated global primary or export production for either misfit metric employed. However, a relatively tight relationship that is very similar for the different model of different structural complexity is found between the model‐data misfit in oxygen and phosphate distributions to simulated meso‐ and bathypelagic particle flux. Best agreement with the observed tracer distributions is obtained for simulated particle fluxes that agree most closely with sediment trap data for a nominal depth of about 1000 m, or deeper.