A sulfur hexafluoride section in the North Pacific Ocean: Application of a dual tracer approach

北太平洋在吸收和储存人为二氧化碳方面发挥着重要作用。根据过去使用化学示踪剂的研究，北太平洋已被确定为气候变化导致海洋二氧化碳通风率变化的关键区域。在以前的研究中使用的化学示踪剂所得到的数据仅描述了部分二氧化碳传输时间尺度，并且受到海洋混合的强烈影响。为了加强示踪剂结果的使用，来自华盛顿大学的两位海洋化学家计划利用双重化学示踪剂来提供更准确的温跃层通风、氧气利用和人为二氧化碳吸收率的测定。通过在双示踪剂方法中结合使用氟氯化碳（CFCs）和六氟化硫（SF6）作为示踪剂，本研究的结果将改进CO2传递时间分布（TTD），并在计算更准确的CO2通风率时隐含地考虑海洋混合。这些酸化率和通风率的估计对于理解全球气候变化的影响具有重要意义，包括海洋人为CO2吸收、海洋酸化、生物输出率和年代际气候变率。至于更广泛的影响，作为该项目的一部分，将支助和培训一名研究生。一名本科生将参加此次巡游，学习如何测量微量气体，所得数据将为其本科研究项目提供依据。

The North Pacific Ocean plays an important role in the uptake and storage of anthropogenic CO2. According to past research using chemical tracers, the North Pacific Ocean has been identified as a critical region where climate variability is causing changes in oceanic CO2 ventilation rates. Chemical tracers used in previous research, have resulted in data describing only a portion of CO2 transit timescales and were strongly affected by oceanic mixing. To enhance the use of tracer results, two ocean chemists from the University of Washington plan to utilize dual chemical tracers to provide more accurate determinations of thermocline ventilation, oxygen utilization, and anthropogenic CO2 uptake rates. By combining the use of chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF6) as the tracers in a dual tracer approach, the results from this research would refine CO2 transit time distributions (TTD) and implicitly account for ocean mixing while calculating more accurate CO2 ventilation rates. The estimations of these acidification and ventilation rates are of significance to the understanding of the implications of global climate change including anthropogenic CO2 uptake by the oceans, ocean acidification, biological export rates, and decadal climate variability.As regards broader impacts, one graduate student would be supported and trained as part of this project. One undergraduate student would participate in the cruise, learn how to measure trace gases, and the data would provide the basis for his/her undergraduate research project.