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

这一重大研究仪器奖支持开发具有足够精度的下一代气体质谱仪系统，以测量由于化石燃料燃烧而导致的海洋变暖速度。这种方法的工作原理是测量大气中的氪和氙气的丰度，随着时间的推移，由于温水比冷水含有更少的溶解气体，这些丰度正在上升。这些测量用一种完全独立的方法补充了从浮标和船只上直接观测到的海洋温度，这种方法利用大气的良好混合性质在一个地点跟踪体积平均海洋热量。考虑到来自温室气体的93%的多余热量最终进入海洋，这种方法是一种经济高效的方式，可以增加社会对这一关键的地球生命迹象的认识。气体质谱仪系统还可以测量冰芯中滞留空气过去的大气氧浓度，这将提高对土壤变暖时温室气体排放的科学理解。这项工作的更广泛影响包括对一名博士生的教育，以及将使用该仪器的两个未被充分代表的少数民族的研究职业发展。海洋过剩热量清单以相当直接的方式反映了由于人类辐射强迫而导致的大气顶部的累积能量失衡。原则上，更好地了解过去半个世纪的海洋热含量将缩小灵敏度估计的不确定性，过去50年来，灵敏度一直保持在3+-1.5摄氏度。斯克里普斯二氧化碳计划在过去50年里采集的存档空气样本将使用拟议的设备测量氪和氙气的浓度，看看是否有可能改善海洋热的历史记录，从而减少灵敏度的不确定性。该技术战略基于购买工厂改装的MAT 253超质谱计，以及已经在斯克里普斯海洋研究所使用的定制稳压进气系统。平行的传统进气系统将使仪器能够无摩擦地共享用于其他目的，例如需要高质量分辨率以将干扰质量从感兴趣的物种中分离出来的气体测量，或稀有同位素和非质量独立分馏的研究。这项提议将在斯克里普斯建立高级同位素地球化学共用设施，这将支持变革性的新发现并吸引年轻研究人员。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.