GEOTRACES Atlantic Section: Measurement of Helium Isotopes and Tritium

GEOTRACES 大西洋部分：氦同位素和氚的测量

• 批准号: 1132522
• 负责人: William Jenkins
• 金额: $ 1.77万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-15 至 2012-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1132522&HistoricalAwards=false
• 关键词: GEOTRACES; Atlantic; Section; Measurement; Helium

This Grant for Rapid Response Research (RAPID) will provide funding to a research team at the Woods Hole Oceanographic Institution to continue their collection of tritium and helium isotope samples on the interrupted GEOTRACES North Atlantic Zonal Section originally funded through an NSF ARRA award. Due to the mechanical failure of the research vessel KNORR's propulsion system, the original cruise was cut short about one third of the way through, and most of the scientific party was obliged to disembark in Cape Verde Islands. Extra effort is required to refurbish sampling vessels and re-stage the sampling effort for the second cruise set for October, 2011. The research team will make helium isotope and tritium measurements to provide useful biogeochemical rate information for the more centrally important TEI measurements made on the continuation of the first U.S. GEOTRACES global survey section. The primary contributions that tritium and 3He measurements can make to the program include: (1) Quantifying transit timescales and TEI dilution in the MOC: 3H and 3He are useful tracers for determining deep western boundary current tracer transport rates and interior mixing dilution scales, an important issue for many TEIs.(2) As a shallow water chronometer: using the tritium-3He clock, we can determine the time elapsed since fluid parcels have been subducted on timescales ranging from 6 months to several decades. We can also combine 3H - 3He ages and evolving 3H and 3He distributions with geostrophy, T,S, O2, nutrient, and TEI distributions to estimate transformation rates. (3) A TEI thermocline reflux gauge: 3He e is a unique ?nutrient-like? transient tracer that can be used as a so-called flux gauge to determine the rates at which thermocline-remineralized TEIs are returned to the upper ocean. This is important for biogeochemical models. (4) Gauging TEI hydrothermal dilution scales: Volcanic 3He injected during hydrothermal activity is a powerful conservative tracer of dilution in these plumes, allowing diagnosis of non-conservative behavior in some TEIs, and permitting flux estimates associated with hydrothermal activity on basin and global scale. The P.I. will be responsible for the acquisition, measurement, interpretation and modeling of the tritium and 3He to achieve the above objectives. Broader Impacts: The proposed work is in support of the GEOTRACES program, as such contributes to the broader societal goals and intellectual objectives espoused by that program. The primary issues related to this are pertinent to understanding the carbon cycle and predicting/mitigating climate change, as well as the marine food web and anthropogenic impacts on the oceans.

这项快速响应研究拨款 (RAPID) 将为伍兹霍尔海洋研究所的一个研究团队提供资金，以继续在中断的 GEOTRACES 北大西洋分区上收集氚和氦同位素样本，这些样本最初是通过 NSF ARRA 奖项资助的。由于克诺尔号科考船推进系统出现机械故障，原定巡航行程缩短了约三分之一，大部分科考队被迫在佛得角群岛下船。需要付出额外的努力来翻新采样船，并为 2011 年 10 月的第二次巡航重新安排采样工作。研究小组将进行氦同位素和氚测量，为在首次美国 GEOTRACES 全球调查部分的延续。氚和 3He 测量对该计划的主要贡献包括： (1) 量化 MOC 中的渡越时间尺度和 TEI 稀释： 3H 和 3He 是有用的示踪剂，可用于确定深部西边界电流示踪剂输运速率和内部混合稀释尺度，对于许多 TEI 来说，这是一个重要的问题。(2) 作为浅水计时器：使用氚-3He 时钟，我们可以确定自流体团在时间尺度上俯冲以来所经过的时间时间从6个月到几十年不等。我们还可以将 3H - 3He 年龄以及不断演变的 3H 和 3He 分布与地转、T、S、O2、营养物和 TEI 分布相结合来估计转化率。 (3) TEI 温跃层回流计：3He e 是一种独特的“类营养物”。瞬态示踪剂，可用作所谓的通量计，以确定温跃层再矿化的 TEI 返回上层海洋的速率。这对于生物地球化学模型很重要。 (4) 测量 TEI 热液稀释规模：热液活动期间注入的火山 3He 是这些羽流中稀释的强大保守示踪剂，允许诊断某些 TEI 中的非保守行为，并允许对盆地和全球范围内的热液活动进行通量估计。 P.I.将负责氚和 3He 的采集、测量、解释和建模，以实现上述目标。更广泛的影响：拟议的工作是为了支持 GEOTRACES 计划，因为这有助于实现该计划所支持的更广泛的社会目标和知识目标。与此相关的主要问题涉及了解碳循环和预测/缓解气候变化，以及海洋食物网和人为对海洋的影响。