Oxygen Utilization and Nutrient Remineralization Rates in the Pacific Ocean (Supplement to Continuation of Models of the Pacific Basin Circulation Based on WOCE-era Observations)

生物地球化学循环将在太平洋的多箱逆模式中进行研究，重点是氧气利用和营养物质再矿化速率。该反模式是在以前的赠款下开发的，首次纳入了在太平洋收集的所有主要WOCE水文断面，以确定密度层内的纬向和经向输送，以及昼夜通量和海-气交换通量。生物地球化学通量将被添加到模型中，以在盆地尺度上调查氧气消耗的深度相关速率以及真光带以下产生的硝酸盐、磷酸盐、硅酸盐和总碱度(TA)。这一逆模型的表述不同于以前的模型，因为生物地球化学源/汇项被明确地作为未知数包括在内。通过合并这些术语，有可能对生物地球化学速率施加限制。我们建议进行一系列模型实验来探索这一方法，包括通过Redfield比率耦合氧气利用和磷酸盐和硝酸盐的再矿化速率，引入对生物地球化学速率的非零初始猜测，以及施加正/负约束。此外，实验将改变模型方程的权重，预定义垂直扩散系数，并唤起自上而下的养分守恒。氧气利用率和养分/TA的最佳估计值。再矿化率将与基于示踪剂年龄的方法和文献中其他研究的结果进行比较，从中可以推断出有机物、蛋白石和碳酸钙(CaCO3)的出口率。更广泛的影响：这项工作形成了正在进行的国际WOCE计划期间收集的数据综合的跨学科组成部分。它还代表了反方法(在物理海洋学中广泛使用)在生物地球化学速率推断中的一种新应用。由此得出的有机碳和CaCO3再矿化率的估计将有助于研究全球碳循环中的海洋部分。这笔资金将支持一名博士后研究员，她正在跨学科研究领域建立自己的地位，并对进一步结合物理和生物地球化学方法感兴趣。

ABSTRACTOCE-0326162Biogeochemical cycling will be studied in a multi-box inverse model of the Pacific Ocean with focus on oxygen utilization and nutrient remineralization rates. The inverse model was developed under previous grants incorporating for the first time all the main WOCE hydrographic sections collected in the Pacific Ocean to determine zonal and meridional transports within density layers as well as diapycnal fluxes and air-sea exchange fluxes. Biogeochemical fluxes will be added in the model to investigate, on basin-scale, the depth-dependent rates at which oxygen is consumed and nitrate, phosphate, silicate, and total alkalinity (TA) are produced below the euphotic zone. The formulation of this inverse model differs from previous models in that the biogeochemical source/sink terms are explicitly included as unknowns. Through the incorporation of these terms, it is possible to put constraints on the biogeochemical rates. We propose to perform a set of model experiments to explore this approach including coupling of oxygen utilization and phosphate and nitrate remineralization rates through Redfield ratios, introducing non-zero initial guesses for the biogeochemical rates, and imposing positivity/negativity constraints. In addition, experiments will be conducted with varying the weights of the model equations, predefining the vertical diffusivities, and evoking top-to-bottom nutrient conservation. The best estimates of oxygen utilization and nutrient/TA. remineralization rates, from which organic matter, opal, and calcium carbonate (CaCO3) export rates can be inferred, will be compared to results from tracer age based approaches and other studies in the literature. Broader Impacts: This work forms an interdisciplinary component of the ongoing synthesis of the data collected during the international WOCE program. It also represents a novel application of inverse methods (widely used in physical oceanography) to the inference of biogeochemical rates. The resulting estimates of organic carbon and CaCO3 remineralization rates will benefit the study of the oceanic component of the global carbon cycle. The funds will support a postdoctoral investigator who is in the process of establishing herself in interdisciplinary research and is interested in further combining physical and biogeochemical approaches.