MRI: Development of an Ultra-High-Precision Gas Mass Spectrometer

这项重大研究仪器奖支持开发下一代气体质谱系统，该系统具有足够的精度来测量由于化石燃料燃烧而导致的海洋变暖速率。该方法的工作原理是测量大气中氪和氙的丰度随着时间的推移，这是上升，由于事实上，温水持有溶解气体比冷水少。这些测量补充了直接海洋温度观测从浮子和船舶与一个完全独立的方法，它利用大气的良好混合的性质，跟踪体积平均海洋热量在一个单一的位置。考虑到93%的温室气体产生的多余热量最终都进入了海洋，这种方法是一种具有成本效益的方法，可以增加社会对这一关键行星生命体征的信心。气体质谱系统还可以测量冰芯中被困空气中过去的大气氧浓度，这将提高对土壤变暖时温室气体释放的科学理解。这项工作的更广泛影响包括一名博士生的教育，以及两名将使用该工具的代表性不足的少数民族的研究职业发展。过量海洋热量的清单以一种相当直接的方式反映了由于人类辐射强迫而在大气层顶部累积的能量不平衡。原则上，如果能更好地了解过去半个世纪的海洋热含量，就能缩小敏感度估计值的不确定性，过去50年的敏感度估计值为3+-1.5摄氏度。斯克里普斯CO2计划在过去50年中采集的存档空气样本将使用拟议的设备测量氪和氙浓度，以查看是否有可能改善海洋热量的历史记录，从而降低灵敏度的不确定性。技术战略的基础是购买一台工厂改装的MAT 253 Ultra质谱仪，并结合斯克里普斯海洋研究所已在使用的定制压力稳定入口系统。一个平行的传统入口系统将使无摩擦共享使用的仪器用于其他目的，如气体测量，需要高质量分辨率，以分离干扰质量从感兴趣的物种，或研究稀有同位素和质量无关的分馏。该计划将在斯克里普斯建立一个共享的高级同位素地球化学设施，这将支持变革性的新发现并吸引年轻的研究人员。该奖项反映了NSF的法定使命，并通过使用基金会的知识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 Major Research Instrumentation award supports development of a next-generation gas mass spectrometry system with sufficient precision to measure the rate of ocean warming due to fossil fuel burning. The method works by measuring the atmosphere's krypton and xenon abundances over time, which are rising due to the fact that warm water holds less dissolved gas than cold water. These measurements complement the direct ocean temperature observations from floats and ships with a completely independent method, which takes advantage of the well-mixed nature of the atmosphere to track volume-average ocean heat at a single location. Given that 93% of the excess heat from greenhouse gases ends up in the ocean, this approach is a cost-effective way to add confidence to society's knowledge of this crucial planetary vital sign. The gas mass spectrometry system also enables measurement of past atmospheric oxygen concentrations from trapped air in ice cores, which will improve scientific understanding of release of greenhouse gases from soils as they warm. Broader impacts of the work include education of one PhD student, and the research career development of two under-represented minorities who will use the instrument. The inventory of excess ocean heat reflects in a rather direct way the cumulative energy imbalance at the top of the atmosphere due to human radiative forcing. In principle, a better knowledge of ocean heat content over the past half century would narrow the uncertainty on the estimate of sensitivity, which has been at 3+-1.5 degrees C for the last 50 years. Archived air samples taken by the Scripps CO2 program over the past 50 years will be measured for krypton and xenon concentration, using the proposed equipment, to see if it is possible to improve the historical record of ocean heat, and thereby reduce the uncertainty on the sensitivity. The technological strategy is based on purchase of a factory-modified MAT 253 Ultra mass spectrometer, combined with a custom pressure-stabilized inlet system already in use at the Scripps Institution of Oceanography. A parallel conventional inlet system will enable frictionless shared use of the instrument for other purposes, such as gas measurements that require high mass resolution to separate interfering masses from the species of interest, or studies of rare isotopologues and mass-independent fractionation. This proposal will establish a shared-use Facility for Advanced Isotope Geochemistry at Scripps, which will underpin transformative new discoveries and attract young researchers.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.