M161 Continuous In-situ Water Vapor Isotopic Composition

A Picarro L2130-i cavity ring-down spectrometer was deployed aboard the Research Vessel Meteor during M161 cruise of the EUREC4A field campaign. Measurements were taken nearly continuously from Jan 18th – Feb 21st 2020 in an area of the North Atlantic typically a few hundred kilometers east of Barbados. Relatively undisturbed air was sampled via an inlet placed at ~25.8 m above the mean sea surface with a forward-facing fetch (above the bow). Air then passed through an inlet line of 505 cm length which was heated to prevent condensation. Periods with winds between 120 and 250 degrees relative to the bow were excluded (masked) to avoid contamination by ship emissions. Daily calibration runs were done throughout the cruise using a rotation of four reference standards. Post-processing included concentration dependence corrections and VSMOW-SLAP normalization. Missing data points due to instrument issues, calibration runs, wind mask are filled with value 9.969209968386869e+36.

本研究在EUREC4A野外试验计划（EUREC4A field campaign）的M161航次（M161 cruise）期间，将Picarro L2130-i型腔衰荡光谱仪（Picarro L2130-i cavity ring-down spectrometer）部署于流星号研究船（Research Vessel Meteor）上。测量工作于2020年1月18日至2月21日期间近乎连续完成，采样区域位于北大西洋巴巴多斯以东数百公里的海域。研究团队通过布置在平均海面以上约25.8米、位于船首上方的正向前方进气口采集相对未受干扰的空气。空气随后流经一段长度为505厘米的加热进气管路，以防止水汽凝结。本研究排除了相对船首方位角介于120度至250度之间的风向时段并进行掩膜处理，以规避船舶排放物带来的污染。整个航次期间，通过轮换使用4种参考标准开展每日校准作业。后处理流程包含浓度依赖性校正与VSMOW-SLAP归一化处理。因仪器故障、校准作业及风向掩膜导致的缺失数据点，均以9.969209968386869e+36进行填充。