Net Biological Oxygen Production Using O2 Measurements on Argo Floats

使用 Argo 浮标上的 O2 测量得出净生物产氧量

• 批准号: 1129112
• 负责人: Steven Emerson
• 金额: $ 78.6万
• 依托单位: University of Washington
• 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: 2011-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1129112&HistoricalAwards=false
• 关键词: Net; Biological; Oxygen; Production; Using

It is now possible to envision global-scale measurements of accurate, seasonal variations of oxygen concentrations in the upper 2000 meters of the ocean by improving the quality of in situ oxygen measurements. These measurements can presently be made remotely by floats, moorings, and gliders. Analysis of data returned so far from oxygen sensors on Argo floats indicates that accuracy of these measurements is presently not sufficient to solve the pressing problems of air-sea oxygen exchange and slow decadal-scale O2 change in the thermocline. However, recent work with oxygen measurements on moorings and gliders suggest that it is possible to determine oxygen concentrations using available sensors to better than +/- 0.5 % accuracy if calibration protocols are established, which would be sufficient to address these problems. In this project, researchers at the University of Washington hope to demonstrate this using float-based Aanderaa Optode sensors calibrated before and during float deployment in a location of strategic oceanographic interest -- the Northwest Pacific Kuroshio Extension. This is a region of intense pCO2 draw down in winter caused by a combination of physical and biological processes. The team will evaluate the relative importance of biological processes in creating the carbon sink by determining the net biological oxygen production from O2 data determined on floats and on a surface mooring in the area. The project thus has two main goals: (1) to test the procedures necessary to improve accuracy of in situ oxygen measurements on profiling floats so that a protocol for future expansion of O2 sensor deployment can be developed; and (2) to determine the role of biological production in controlling the dramatic wintertime draw-down of surface ocean pCO2 in the Northwest Pacific Ocean. The team will deploy 10 Argo floats (constructed at Argo expense) with oxygen sensors in the Kuroshio Extension region. An oxygen sensor and gas tension device will also be deployed on an existing surface mooring in the region to derive a much more detailed data time series to compare with the float measurements. The oxygen sensors will be calibrated both in the laboratory before deployment and in situ in the ocean after deployment by comparing their output to measurements by Winkler titration. The floats will be programmed to make measurements in the atmosphere when they surface to transmit data to shore via satellite as a means of in situ calibration. With this calibration redundancy they will be able to determine the protocol necessary to achieve accurate in situ O2 data on a much broader scale with less extensive calibration. Broader Impacts. Broader impacts to the marine research community include development of a protocol for calibration of O2 sensors so they can be used more broadly in situ on autonomous platforms. Broader impacts to education involve a "student cruise" on the University of Washington research vessel RV T.G. Thompson. This cruise will expose 10-15 undergraduate students to the experience of field oceanography and marine research, while fulfilling their required capstone research for the undergraduate oceanography degree. The University of Washington has committed twelve days of the ship time to accommodate the educational aspects of the study.

现在可以设想通过提高原位氧气测量的质量，对海洋上层 2000 米的氧气浓度进行精确的季节性变化测量。这些测量目前可以通过浮标、系泊装置和滑翔机远程进行。对迄今为止从Argo浮标上的氧气传感器返回的数据进行的分析表明，这些测量的准确性目前不足以解决空气-海洋氧气交换和温跃层中缓慢的十年尺度氧气变化的紧迫问题。然而，最近对系泊装置和滑翔机上氧气测量的研究表明，如果建立了校准协议，则可以使用可用的传感器确定氧气浓度，其精度优于 +/- 0.5%，这足以解决这些问题。在该项目中，华盛顿大学的研究人员希望使用基于浮标的 Aanderaa Optode 传感器来证明这一点，这些传感器在具有战略海洋学意义的地点（西北太平洋黑潮延伸区）的浮标部署之前和期间进行了校准。由于物理和生物过程的共同作用，该地区在冬季 pCO2 急剧下降。 该团队将通过根据浮标和该区域表面系泊处确定的氧气数据确定净生物氧气产量，来评估生物过程在创建碳汇方面的相对重要性。 因此，该项目有两个主要目标：(1) 测试提高剖面浮标原位氧气测量精度所需的程序，以便制定未来扩展 O2 传感器部署的协议； (2) 确定生物生产在控制西北太平洋冬季表层二氧化碳二氧化碳浓度急剧下降中的作用。该团队将在黑潮延伸区部署 10 个带有氧气传感器的 Argo 浮标（由 Argo 出资建造）。氧气传感器和气体张力装置也将部署在该地区现有的表面系泊处，以获得更详细的数据时间序列，以便与浮标测量结果进行比较。氧气传感器将在部署前在实验室中以及部署后在海洋中进行校准，将其输出与温克勒滴定的测量结果进行比较。这些浮标将被编程为在浮出水面时在大气中进行测量，并通过卫星将数据传输到岸上，作为现场校准的一种手段。有了这种校准冗余，他们将能够确定在更广泛的范围内以较少的校准获得准确的原位 O2 数据所需的协议。更广泛的影响。对海洋研究界更广泛的影响包括制定氧气传感器校准协议，以便它们可以在自主平台上更广泛地原位使用。对教育的更广泛影响包括华盛顿大学研究船 RV T.G. 的“学生巡游”。汤普森. 这次航行将使 10-15 名本科生体验实地海洋学和海洋研究的经验，同时完成本科海洋学学位所需的顶点研究。华盛顿大学投入了十二天的航行时间来满足该研究的教育方面的需要。