Shipboard measurements of atmospheric oxygen using a vacuum-ultraviolet absorption technique
Shipboard measurements of atmospheric oxygen using a vacuum-ultraviolet absorption technique
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使用真空紫外线吸收技术进行船上大气氧测量
DOI：
10.3402/tellusb.v55i4.16386
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
W. Paplawsky
中科院分区：
文献类型：
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作者：
B. Stephens;R. Keeling;W. Paplawsky
我们开发了一种仪器，用于对大气氧浓度进行连续、实地、百万分之一（ppm）水平的测量，并在赤道太平洋和南大洋的研究航行中使用。该仪器通过吸收真空紫外线（VUV）辐射来检测氧气的变化，因为它通过流动的气流，并具有与现有实验室技术相当的精度。本文介绍了1998年4月和5月在赤道太平洋的NOAA船Ka'imimoana和NSF船Lawrence M. 1998年10月在南大洋的古尔德号。这些数据代表了第一个基于现场的大气O2测量，并在这些地区的O2数据集的显着增加。我们的北方春季赤道测量揭示了大气中O2的显着的短期变化，导致大气混合相对于强半球间梯度的变化。我们的南方春季南大洋观测证实了该地区烧瓶样本中的低O2浓度，允许单独识别海洋和工业对CO2的影响，并提供了每年这个时候南大洋CO2来源的证据。这些船载真空紫外观测没有提供任何证据来支持耦合海洋-大气模型预测的赤道和高南纬度之间的大气O2梯度大幅度下降。
We have developed an instrument for making continuous, field-based, part-per-million (ppm) level measurements of atmospheric oxygen concentration, and have implemented it on research cruises in the equatorial Pacific and Southern Oceans. The instrument detects changes in oxygen by the absorption of vacuum ultraviolet (VUV) radiation as it passes through a flowing gas stream, and has a precision comparable to existing laboratory techniques. Here we describe the VUV instrument and present atmospheric O2 and CO2data collected from the NOAA ship Ka’imimoana in the equatorial Pacific during April and May of 1998, and from the NSF ship Lawrence M. Gould in the Southern Ocean during October 1998. These data represent the first field-based measurements of atmospheric O2, and significant additions to the O2 datasets in these regions. Our boreal-springtime equatorial measurements reveal significant short-term variations in atmospheric O2, resulting from variations in atmospheric mixing relative to the strong interhemispheric gradient. Our austral-springtime Southern Ocean observations confirm the low O2 concentrations seen in flask samples from this region, allow the separate identification of oceanic and industrial influences on CO2, and provide evidence of a Southern Ocean source for CO2 at this time of year. These shipboard VUV observations do not provide any evidence to support coupled ocean—atmosphere model predictions of a large decreasing atmospheric O2 gradient between equatorial and high-southern latitudes.