Collaborative Research: Improving the accuracy and uncertainty associated with estimated pCO2 from pH sensors on autonomous profiling platforms

协作研究：提高自主分析平台上 pH 传感器估计 pCO2 的准确性和不确定性

• 批准号: 2049117
• 负责人: Yuichiro Takeshita
• 金额: $ 79.39万
• 依托单位: Monterey Bay Aquarium Research Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049117&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; accuracy; uncertainty; Collaborative; Research; Improving; accuracy; uncertainty

Understanding how much anthropogenic carbon dioxide the ocean is taking up from the atmosphere - and how this uptake changes over time - is critical for understanding the habitability of our planet. Uncertainties in the size of the ocean carbon sink remain large, mainly because of sparse measurements of surface water carbon dioxide (pCO2) measurements from ships. Profiling floats equipped with sensors for biogeochemical (BGC) measurements such as pH – which can be used to estimate pCO2 – have the potential to greatly improve the amount of surface carbon dioxide observations across the world’s ocean, particularly in regions and times of year where shipboard measurements are scarce. The number of BGC floats deployed worldwide is expected to rapidly increase in the coming years through programs like the Global Ocean Biogeochemistry Array (GO-BGC) and the Southern Ocean Carbon and Climate Observations and Modeling program (SOCCOM2). However, there are still fundamental issues that need to be resolved before we can take full advantage of this emerging, powerful global observational network to improve our estimates of how much anthropogenic carbon the ocean absorbs every year. The overarching aim of this project is to improve the accuracy and precision of pCO2 estimates that are derived from profiling float data. The project will support a postdoctoral researcher and three undergraduate summer interns.This project seeks to improve the accuracy and uncertainty associated with float-based estimates of pCO2 by addressing the outstanding questions and issues that could lead to systematic biases in these calculations. Specifically, the investigators aim to answer the following questions: 1) What causes the pressure-dependent discrepancy between bottle and float pH? 2) What is the source of the internal inconsistency of the thermodynamic marine inorganic carbon model, which affects the accuracy of pCO2 computed from pH measurements? 3) What are the global spatiotemporal patterns of acidification rate at 1500 m, and how do we model the patterns accurately? The team will conduct a series of laboratory studies to quantify key thermodynamic constants, test the hypothesis that organic compounds are a substantial contributor for the internal inconsistency, and determine a robust protocol to accurately calculate pCO2 from pH. Furthermore, an open-source, global algorithm will be made available that accurately predicts region-specific anthropogenic carbon estimates, which is necessary to accurately correct float pH sensor drift globally. Finally, to assess the improvement in accuracy of float based pCO2 estimates based on these efforts, the team will conduct a series of field validation experiments using Spray underwater gliders equipped with the same pH sensor as profiling floats, and a Wave Glider, an autonomous surface vehicle that is equipped with a pCO2 analyzer calibrated with gas standards with an accuracy of plus or minus two microatmospheres. Over the course of the project, the team will test 16 different pH sensors to better constrain the potential systematic biases for the float based pCO2 estimates. The activities outlined here will lead to more accurate estimates of pCO2 from floats, as well as better constrained uncertainties, and ultimately lead to better estimates for air-sea CO2 flux from the global network of BGC profiling floats.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.

了解人类二氧化碳从大气中占用了多少 - 这种吸收随着时间的变化对于理解我们星球的可居住性至关重要。海洋碳水槽大小的不确定性仍然很大，这主要是由于船舶的地表水二氧化碳（PCO2）测量很少。配备配备有生物地球化学（BGC）测量的传感器（可用于估算PCO2）的浮子有可能极大地改善全球海洋各地的二氧化碳观测量，尤其是在一年中的地区和一年中的时代，造船板测量很少。预计在未来几年中，通过全球海洋生物地球化学阵列（GO-BGC）以及南大洋碳和气候观察和建模计划（SOCCOMC2）等计划，全球部署的BGC浮子数量预计将在未来几年迅速增加。但是，在我们充分利用这个新兴，强大的全球观察网络以改善我们对每年海洋吸收多少人为碳吸收多少的估计之前，仍需要解决一些基本问题。该项目的总体目的是提高根据分析浮点数据得出的PCO2估计值的准确性和精度。该项目将支持一名博士后研究人员和三个本科夏季Inters。该项目旨在通过解决可能导致这些计算中系统性偏见的杰出问题和问题来提高与基于浮点的PCO2估计相关的准确性和不确定性。具体问题，研究人员旨在回答以下问题：什么会导致压力依赖的瓶子和弗洛（Flotep）之间的瓶装和弗洛（Floot）之间的压力和弗洛（Floot）之间的压力和浮花率之间的浮标和浮点（Floot）和弗洛特（Floot）和弗洛特（Floot）和弗洛特（Floot）之间的质量ph？ 2）热力学海洋无机碳模型的内部不一致性的来源是什么，这会影响从pH测量结果计算的PCO2的准确性？ 3）在1500 m处的酸化速率的全局空间时间模式是什么，我们如何准确地对模式进行建模？该团队将进行一系列实验室研究，以量化关键热力学常数，检验有机化合物是内部不一致的重要贡献的假设，并确定可靠的方案以准确地从pH中计算PCO2。此外，将提供一种开源的全局算法，该算法可以准确预测特定区域的人为碳估计值，这对于准确纠正浮动pH传感器在全球范围内漂移是必不可少的。最后，为了根据这些努力评估基于浮点的PCO2估计的准确性的提高，该团队将使用配备了与配置浮球的pH传感器相同的pH传感器的喷雾水下滑翔机进行一系列现场验证实验，以及一种自动层面的浮雕，一种自主表面工具，该工具与PCO2分析器配备了PCO2分析仪，并通过PCO2分析校准了与精度或MANUS的精确度校准的PCO2分析。在项目过程中，团队将测试16个不同的pH传感器，以更好地限制基于浮点的PCO2估计值的潜在系统偏见。此处概述的活动将导致从浮标中对PCO2进行更准确的估计，以及更好地限制的不确定性，并最终从BGC概况的全球网络中对空气SEA CO2通量进行更好的估计。这奖反映了NSF的立法任务，并通过使用基础的智力评估来评估支持NSF的立法任务，并被认为是诚实的。