WOCE AIMS: Analysis of Tracer Ages and Estimate of Isopycnal Mixing

[0136973] fine这个项目的目标是估计单个示踪剂年龄的不确定性，并将这些不确定性的大小差异与已知的环流现象联系起来。重点是温跃层和中间水团，使用最近获得的世界海洋环流实验（WOCE）氯氟烃和氚/氦-3数据。示踪剂年龄是衡量海洋将大气成分输送到内部的能力。在等环流混合能显著改变示踪剂年龄的副热带环流区域，将计算等环流混合率。示踪剂年龄的误差由分析、源函数和其他因素引起。这里将对示踪剂年龄和分布的误差进行区分。与海洋过程的影响相比，误差对示踪剂年龄分布的影响很小。根据混合的程度和途径，示踪剂可以在给定的水团中显示出广泛的年龄分布。因此，混合会降低解释示踪剂年龄的能力；也就是说，从一个水包与大气接触以来所经过的时间。混合历史将通过用公认的理论框架分析示踪剂年龄的分布来评估。将计算副热带环流子区域的等环流混合率和小波数。这些值将与示踪剂年龄分布和非线性混合项进行比较。这项工作将使用北大西洋的高分辨率数值模式进行扩展，该模式假定为静止环流。这将允许分析模拟CFC和理想年龄、它们的分布、与观测值的比较以及评估模式中的通风和混合。所提出的多重示踪剂方法的结果将有助于量化海洋吸收大气气体（例如二氧化碳）的速率。

0136973 FineThe goal of this project to estimate the uncertainties for individual tracer ages, and to associate differences in the magnitude of these uncertainties with known circulation phenomena. The focus is on thermocline and intermediate water masses, using World Ocean Circulation Experiment (WOCE) chlorofluorocarbon and tritium/helium-3 data that have recently become available. Tracer ages are a measure of the ocean's ability to transport atmospheric constituents into the interior. Isopycnal mixing rates will be calculated for regions of the subtropical gyres where isopycnal mixing can significantly alter tracer ages. Errors in tracer ages arise from analytical, source function, and other factors. Here a differentiation will be made between errors in tracer ages and distributions. The effect of errors on tracer age distributions is small compared with effects of oceanic processes. Depending on the extent and pathways of mixing, a tracer can exhibit a broad distribution of ages within a given water mass. Mixing, therefore, compromises the ability to interpret tracer ages; i.e., the elapsed time since a water parcel was in contact with the atmosphere. Mixing histories will be assessed by analyzing distributions of tracer ages with an accepted theoretical framework. Isopycnal mixing rates and Peclet numbers will be calculated for sub-regions of the subtropical gyres. These values will be compared to tracer age distributions and non-linear mixing terms. The work will be extended using a high resolution numerical model of the North Atlantic with an assumed stationary circulation. This will permit analysis of simulated CFC and ideal ages, their distributions, comparison with observations, and assessment of ventilation and mixing in the model. Results from the proposed multiple tracer approach will contribute toward quantifying the rate at which the ocean takes up atmospheric gases, for example, CO2.