The AquaVIT-1 intercomparison of atmospheric water vapor measurement techniques
The AquaVIT-1 intercomparison of atmospheric water vapor measurement techniques
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DOI：
10.5194/amt-7-3177-2014
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发表时间：
2014-01-01
影响因子：
3.8
通讯作者：
Wienhold, F. G.
中科院分区：
文献类型：
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作者：
Fahey, D. W.;Gao, R. -S.;Wienhold, F. G.
大气水蒸气测量技术的 AquaVIT-1 相互比较于 2007 年 10 月在德国卡尔斯鲁厄理工学院的气溶胶和云模拟室 AIDA（大气中的气溶胶相互作用和动力学）进行。总体目标是在受控条件下对最先进的大气湿度计和原型大气湿度计进行相互比较，并与独立的湿度标准进行比较。这项活动是在选定的裁判员的协调下以盲目比对的方式进行的。这项工作的动机是在大气测量中发现了持续的差异，涉及在研究飞机和气球平台上运行的多个仪器，特别是在对流层上层和平流层下层，那里的水蒸气达到最低大气值（低于 10 ppm）。 AIDA 腔室容积为 84 m(3)，多种仪器通过将空气抽取到仪器流量系统中、将仪器放置在腔室内部或通过对腔室体积进行光学采样来分析具有常见水蒸气混合比的空气。比对成功进行了 10 天，期间系统地改变了压力、温度和混合比（50 至 500 hPa、185 至 243 K 和 0.3 至 152 ppm）。在没有公认的参考仪器的情况下，无法确定仪器的绝对精度。为了评估相互比较，参考值被视为测量核心子集的整体平均值。对于这些核心仪器，10 和 150 ppm 水蒸气之间的一致性被认为是良好的，参考值的变化约为 +/- 10% (+/- 1 sigma)。在 1 和 10 ppm 之间最感兴趣的区域中，核心子集协议是公平的，参考值的变化为 +/- 20% (+/- 1 sigma)。每个仪器的精度上限也是从报告的数据中得出的。大气测量的含义是，在飞行中比较期间观察到的较大差异源于与移动平台或非实验室环境相关的其他因素。 AquaVIT-1 的成功为未来与水蒸气或其他物种的比对工作提供了一个模板，这些工作的重点是提高移动平台上大气测量的分析质量。
The AquaVIT-1 intercomparison of atmospheric water vapor measurement techniques was conducted at the aerosol and cloud simulation chamber AIDA (Aerosol Interaction and Dynamics in the Atmosphere) at the Karlsruhe Institute of Technology, Germany, in October 2007. The overall objective was to intercompare state-of-the-art and prototype atmospheric hygrometers with each other and with independent humidity standards under controlled conditions. This activity was conducted as a blind intercomparison with coordination by selected referees. The effort was motivated by persistent discrepancies found in atmospheric measurements involving multiple instruments operating on research aircraft and balloon platforms, particularly in the upper troposphere and lower stratosphere, where water vapor reaches its lowest atmospheric values (less than 10 ppm). With the AIDA chamber volume of 84 m(3), multiple instruments analyzed air with a common water vapor mixing ratio, by extracting air into instrument flow systems, by locating instruments inside the chamber, or by sampling the chamber volume optically. The intercomparison was successfully conducted over 10 days during which pressure, temperature, and mixing ratio were systematically varied (50 to 500 hPa, 185 to 243 K, and 0.3 to 152 ppm). In the absence of an accepted reference instrument, the absolute accuracy of the instruments was not established. To evaluate the intercomparison, the reference value was taken to be the ensemble mean of a core subset of the measurements. For these core instruments, the agreement between 10 and 150 ppm of water vapor is considered good with variation about the reference value of about +/- 10% (+/- 1 sigma). In the region of most interest between 1 and 10 ppm, the core subset agreement is fair with variation about the reference value of +/- 20% (+/- 1 sigma). The upper limit of precision was also derived for each instrument from the reported data. The implication for atmospheric measurements is that the substantially larger differences observed during in-flight intercomparisons stem from other factors associated with the moving platforms or the non-laboratory environment. The success of AquaVIT-1 provides a template for future intercomparison efforts with water vapor or other species that are focused on improving the analytical quality of atmospheric measurements on moving platforms.