Collaborative Research: Characterizing the evolving oceanic radiocarbon distribution: Sampling and analysis during GOSHIP and ships of opportunity cruises

该项目支持全球碳同位素示踪剂测量，作为全球海洋船基水文调查方案(GO-SHIP)的一部分。GO-SHIP的美国部分通常每年占据2到3个主要的海洋水文部分。该团队将对其中的一部分进行采样，以确定溶解无机碳(DIC)的14C和13C的变化。这些数据提供了气候和地球系统模型的关键指标，可供更广泛的研究界用于各种科学应用，如气候模型的开发和校准。这两个机构还将努力聘请由单独资助的博士后研究人员，帮助培训下一代科学家。碳同位素数据提供了任何其他测量方法无法获得的关于海洋过程的关键见解：14C提供了人为扰动通过温跃层底部进入深海的十年尺度渗透的高信号/噪声量化。它还通过记录南大洋中间水域向海面的回流，提供了对全球倾覆环流的关键见解。德尔塔14C对于量化海-气二氧化碳气体交换速率至关重要。对于13C，大气-海洋13C不平衡很容易测量，从而量化了海面对人为二氧化碳扰动的吸收。当与海洋内部人为13C变化的累积相结合时，仅通过观测就有可能量化海洋内部人为二氧化碳在盆地范围内的再分配。这些过程很难，如果不是不可能的话，用氯氟烃等人造示踪剂和传统的C系统测量来检查。碳同位素数据的提供将有助于广泛的研究，包括气候变化、海洋人为二氧化碳、温跃层通风、温盐倾覆率、气-海气体交换率、生物循环率以及模型评价或校准。随着航船巡航计划的制定，该团队将仔细评估哪些航段将从有限的分析能力中获得最好的科学回报。采样可能会集中在大西洋和太平洋预计会有强烈信号的长长的经向部分，以及任何其他缺乏测量的地区。水样将被运送到国家海洋科学加速器质谱仪(NOSAMS)进行分析。采样设计、最终质量控制以及向CLIVAR和碳水文数据办公室(CCHDO)和海洋碳数据系统(OCADS)提交数据的工作将在华盛顿大学进行。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project supports the global measurement of carbon isotope tracers as part of the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP). The US component of GO-SHIP typically occupies 2 or 3 major oceanic hydrographic sections per year. The team will sample a subset of these to determine changes in 14C and 13C of dissolved inorganic carbon (DIC). These data provide key metrics for climate and earth-system models and can be used by the broader research community for a diverse set of scientific applications, such as climate model development and calibration. Both institutions will also endeavor to engage postdoctoral researchers supported under separate funding, contributing to the training of the next generation of scientists.Carbon isotopic data affords key insights into ocean processes that are not available from any other measurements: 14C provides high signal/noise quantification of decadal-scale penetration of anthropogenic perturbation through the bottom of the thermocline and into the deep sea. It also provides key insights into the global overturning circulation by documenting return flow of Southern Ocean intermediate waters to the sea surface. Delta 14C is critical to quantifying the air-sea CO2 gas exchange rate. For 13C, the air-sea 13C disequilibrium is readily measured, thus quantifying the uptake of the anthropogenic CO2 perturbation at the sea surface. When combined with the accumulation of anthropogenic 13C changes in the ocean interior, it is possible to quantify basin-scale redistribution of anthropogenic CO2 in the ocean interior from observations alone. These processes are difficult, if not impossible to examine with synthetic anthropogenic tracers like Chlorofluorocarbon and with conventional C system measurements. The availability of carbon isotope data will aid a wide range of studies including climate change, oceanic anthropogenic CO2, thermocline ventilation, thermohaline overturning rates, air-sea gas exchange rates, biological cycling rates, and model evaluation or calibration. As GO-SHIP cruise schedules are planned, the team will carefully evaluate which legs would yield the best science return from the limited analytical capacity. Sampling will likely focus on long, meridional sections in the Atlantic and Pacific oceans where a strong signal is anticipated, and on any other areas where measurements have been lacking. The water samples will be transported to the National Ocean Sciences Accelerator Mass Spectrometry facility (NOSAMS) for analysis. The sampling design, final quality control, and submission of the data to the CLIVAR and Carbon Hydrographic Data Office (CCHDO) and to the Ocean Carbon Data System (OCADS) will be performed at the University of Washington.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.