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

WOCE 目标：示踪剂年龄分析和等密度混合估计

• 批准号: 0136973
• 负责人: Rana Fine
• 金额: $ 65.66万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0136973&HistoricalAwards=false
• 关键词: WOCE; AIMS; Analysis; Tracer; Ages

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.

0136973该项目的目标是估计单个示踪剂年龄的不确定性，并将这些不确定性大小的差异与已知循环现象相关联。重点是使用世界海洋循环实验（WOCE）氯氟化碳和tritium/helium-3数据，这些重点是热级和中间水质量。示踪剂年龄是海洋将大气成分传输到内部的能力的衡量标准。将计算出亚热带回旋区的区域的等法混合速率，在该区域中，等同接受混合可以显着改变示踪剂年龄。示踪剂年龄的错误是由分析，源函数和其他因素引起的。 这里将在示踪剂年龄和分布中之间的错误之间进行区分。与海洋过程的影响相比，错误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质量内表现出广泛的年龄分布。因此，混合损害了解释示踪剂年龄的能力。即，自从水包裹与大气接触以来的经过的时间。将通过公认的理论框架分析示踪剂年龄的分布来评估混合历史。 将针对亚热带回旋的子区域计算等同元混合速率和小子数量。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型进行扩展，并假定为固定循环。 这将允许分析模拟的CFC和理想年龄，它们的分布，与观测值的比较以及对模型中通风和混合的评估。提出的多个示踪剂方法的结果将有助于量化海洋占用大气气体的速率，例如二氧化碳。