SGER: The Utility of the 227Ac and 228Ra Isotope Pair as Tracers of Upwelling Intensity and Lateral Transport

SGER：227Ac 和 228Ra 同位素对作为上升流强度和横向传输示踪剂​​的用途

• 批准号: 0120385
• 负责人: Timothy Shaw
• 金额: $ 5万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-15 至 2003-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0120385&HistoricalAwards=false
• 关键词: SGER; Utility; 227Ac; 228Ra; Isotope

AbstractOCE-0120385Obtaining a suitable tracer that can estimate lateral mixing of shelf waters into the open ocean or can determine the intensity of upwelling in response to ENSO forcing has been hindered by (1) the timescale of these processes (decadal), (2) the fact that simple mixing of radioisotopes with older water masses can result in an aging artifact, and (3) the effects of multiple endmembers. Based on some preliminary results, a PI from the University of South Carolina-Columbia has demonstrated that the activity ratio of 228Ra/227Ac shows great promise as a tracer of lateral mixing processes in the ocean. Because this proposed application is so novel, the PI will use SGER funds to improve the analytical technique for determining these radionuclides and the parent isotopes, as well as carry out additional field tests to verify the utility of this approach. The PI also plans to develop an in-line cartridge system that can be installed on ships of opportunity thereby increasing the spatial distribution of ex228Ra/ex227Ac activity ratios of surface waters to determine the stability of lateral mixing rates on timescales of years to decades.

摘要OCE-0120385获得一种合适的示踪剂来估计陆架沃茨进入公海的横向混合，或确定响应ENSO强迫的上升流强度，这受到以下因素的阻碍：（1）这些过程的时间尺度（十年），（2）放射性同位素与较老水团的简单混合可能导致老化假象，（3）多个端元的影响。 根据一些初步结果，南卡罗来纳大学哥伦比亚分校的一位PI已经证明，228 Ra/227 Ac的活度比作为海洋横向混合过程的示踪剂具有很大的前景。 由于这一拟议的应用是如此新颖，PI将使用SGER资金来改进用于确定这些放射性核素和母同位素的分析技术，并进行额外的现场测试以验证这种方法的实用性。 PI还计划开发一种可安装在机会船上的在线药筒系统，从而增加表面沃茨的ex 228 Ra/ex 227 Ac活性比的空间分布，以确定几年到几十年时间尺度上的横向混合速率的稳定性。