McManus J Barry, Nelson David D, Zahniser Mark S
Aerodyne Research, Inc, Billerica, MA, USA.
Isotopes Environ Health Stud. 2010 Mar;46(1):49-63. doi: 10.1080/10256011003661326.
A recently developed laser spectroscopic instrument allows real-time continuous measurements of the stable isotopologues of carbon dioxide at ambient concentrations. This compact instrument offers sufficient precision (0.2 per thousand in 1 s, 0.02 per thousand in 60 s) and stability (drift in 1 h of<0.2 per thousand), to allow isotopic studies on a variety of timescales and to study a variety of processes. During the development of the instrument, a prototype was set up to sample ambient air nearly continuously for more than 10 months, in a heterogeneous urban area northwest of Boston, MA. During this long sampling experiment, we continued to improve and modify the instrument and sampling system. In this paper, we present data collected during that long sampling experiment in order to demonstrate some of the possibilities provided by such real-time continuous monitoring. We have observed distinct isotopic signatures in CO(2) variations from timescales of seconds to seasons. We also present a method of performing continuous Keeling regressions on a cascade of timescales and show some results in application of that method to the continuous sampling data set.
一种最近开发的激光光谱仪器能够在环境浓度下对二氧化碳的稳定同位素进行实时连续测量。这种紧凑型仪器具有足够的精度（1秒内为0.2‰，60秒内为0.02‰）和稳定性（1小时内漂移<0.2‰），可用于在各种时间尺度上进行同位素研究，并研究各种过程。在仪器开发过程中，在马萨诸塞州波士顿西北部一个异质城区建立了一个原型，对环境空气进行了近10个月的几乎连续采样。在这个长时间的采样实验中，我们不断改进和修改仪器及采样系统。在本文中，我们展示了在那个长时间采样实验中收集的数据，以证明这种实时连续监测所提供的一些可能性。我们在从秒到季节的时间尺度上观察到了二氧化碳变化中明显的同位素特征。我们还提出了一种在一系列时间尺度上进行连续基林回归的方法，并展示了该方法应用于连续采样数据集的一些结果。
