Collaborative Research: Development of SF5CF3 for Ocean Tracer Experiments

合作研究：开发用于海洋示踪剂实验的 SF5CF3

• 批准号: 0425404
• 负责人: William Smethie
• 金额: $ 30.83万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0425404&HistoricalAwards=false
• 关键词: Collaborative; Research; Development; SF5CF3; Ocean

ABSTRACTOCE-0425197Tracer release experiments using sulfur hexafluoride (SF6) in the ocean have proven to be a powerful tool in the study of ocean mixing. An alternative to SF6 is desired because releases of SF6 can interfere with its very promising use as a transient tracer invading the ocean from the atmosphere. Only a small fraction of the ocean has been tainted with SF6 thus far, but in prospect is a tracer release experiment in the Southern Ocean, a region for which SF6 would be very useful as a transient tracer.In this study, researchers at the Woods Hole Oceanographic Institution and Columbia University will evaluate a promising new tracer, trifluoromethyl sulfur pentafluoride (SF5CF3). An important advantage of SF5CF3 is that its background concentration in the ocean is virtually undetectable, while that of SF6 limits the useful duration of prospective tracer release experiments. The researchers have already found that the minimum detectable level of SF5CF3 is as low as that of SF6. A concern about the new tracer is that it may interact with particles in the water strongly enough to not follow the water as well as SF6. Preliminary laboratory measurements of the affinity of SF6 and of SF5CF3 to 1-octanol, to calcium carbonate particles, and to silica particles have shown that transport on particles in the ocean should not be detectable for either compound. On the other hand, SF6 itself seems to have fallen 3 to 10 meters per year in the ocean experiments. Hence they plan to refine and to extend their laboratory measurements. They will also conduct a field test by releasing both tracers together in Santa Monica Basin and following the distributions of the tracers for two years to determine whether SF5CF3 is a viable substitute for SF6 for tracer release experiments. Broader Impacts: Both the study of mixing in the ocean with tracer release experiments and the study of water mass ages using transient tracers are important aspects of the overall study of the ocean circulation and of the ability of the ocean to take up the large amounts of carbon dioxide that are being released to the environment by the burning of fossil fuels. Adding a new tracer to the oceanographic toolkit would contribute significantly to technology, as was demonstrated to be the case when bomb tracers were added in the 1960s, when helium-3 and CFCs were added in the 1970s, and when SF6 was added in the 1980s. SF6 has also been used successfully in transport and dispersion studies in estuaries. The availability of a second tracer would add versatility and power to such experiments. Finally, as an educational component, the researchers will hire an undergraduate student to work each summer to participate in the cruises in Santa Monica Basin and in the laboratory work.

在海洋中使用六氟化硫(SF6)进行示踪释放实验已被证明是研究海洋混合的有力工具。人们需要一种SF6的替代品，因为SF6的释放会干扰其作为一种从大气入侵海洋的瞬时示踪剂的前景。到目前为止，只有一小部分海洋被SF6污染，但有可能在南大洋进行示踪剂释放实验，在该地区，SF6将是非常有用的瞬时示踪剂。在这项研究中，伍兹霍尔海洋研究所和哥伦比亚大学的研究人员将评估一种有前途的新示踪剂--三氟甲基五氟化硫(SF5CF3)。SF5CF3的一个重要优点是它在海洋中的背景浓度几乎是无法检测到的，而SF6的背景浓度限制了未来示踪剂释放实验的有效持续时间。研究人员已经发现，SF5CF3的最低可检测水平与SF6一样低。对这种新示踪剂的一个担忧是，它可能会与水中的颗粒发生足够强烈的相互作用，而不是像SF6那样跟随水。对SF6和SF5CF3对正辛醇、碳酸钙颗粒和二氧化硅颗粒亲和力的初步实验室测量表明，这两种化合物在海洋中的颗粒传输都不应被检测到。另一方面，在海洋实验中，SF6本身似乎每年下降3到10米。因此，他们计划改进和扩大他们的实验室测量。他们还将在圣莫尼卡盆地一起释放这两种示踪剂，并对示踪剂的分布进行两年的跟踪，以确定SF5CF3是否为示踪剂释放实验中可行的SF6替代品。更广泛的影响：利用示踪剂释放实验研究海洋中的混合，以及使用瞬变示踪剂研究水团年龄，都是对海洋环流和海洋吸收燃烧化石燃料向环境释放的大量二氧化碳的能力进行整体研究的重要方面。在海洋学工具包中添加一种新的示踪剂将大大促进技术，正如1960年代添加炸弹示踪剂、1970年代添加氦-3和氯氟化碳以及1980年代添加SF6时所证明的那样。SF6还被成功地用于河口输运和扩散的研究。第二种示踪剂的可获得性将增加此类实验的多功能性和威力。最后，作为教育的一部分，研究人员将雇佣一名本科生每年夏天工作，参加圣莫尼卡盆地的邮轮和实验室工作。