Cloud Chemistry Monitoring at Mt. Brocken, Germany - 1996@en

The liquid water content of clouds (LWC) has been continuously measured using forward scattering of laser beams by cloud droplets with a Particulate Volume Monitor PVM-100 (Gerber Scientific Inc.). This instrument was also used to control an automated „wet-only” sampling unit that opens up and moves a passive string collector (ASRC type) into sampling position when the LWC level exceeds a 25mg/m**3 threshold. The samples were analysed by ion chromatography (DIONEX suppressor, SYKAM pump and conductivity detector, JASCO sampler) for anions ([Cl]-, [NO3]-, [SO4]2-) and cations ([Na]+, [NH4]+, [K]+, [Ca]2+, [Mg]2+), pH and conductivity. The acceptance criteria for ion balance and for conductivity (measured/calculated), respectively, are defined in the Reports 85 (1992) and 102 (1994) of the WMO for all activities within the GAW program and also we did follow rigorously these standard practices. The whole measurement and analytical procedure was laid down in standard operating procedures. […]云液态水含量（Liquid Water Content, LWC）通过颗粒体积监测仪（Particulate Volume Monitor, PVM-100，Gerber Scientific公司出品），借助云滴对激光束的前向散射效应完成连续测量。该仪器同时用于管控一套自动化“纯湿”采样单元：当云液态水含量阈值超过25mg/m³时，该单元会启动并将被动式串式采样器（ASRC型）移至采样位置。采用离子色谱法（ion chromatography），配套DIONEX抑制器、SYKAM泵、电导检测器及JASCO进样器，对采集样品进行分析，检测指标涵盖阴离子（[Cl]⁻、[NO₃]⁻、[SO₄]²⁻）与阳离子（[Na]⁺、[NH₄]⁺、[K]⁺、[Ca]²⁺、[Mg]²⁺）、pH值及电导率。针对离子平衡与电导率（实测值/计算值）的合格判定准则，分别参照世界气象组织（World Meteorological Organization, WMO）1992年第85号报告及1994年第102号报告中针对全球大气监测（Global Atmosphere Watch, GAW）项目所有活动的相关规定，本研究严格遵循了这些标准操作规范。整套测量与分析流程均已在标准作业规程（Standard Operating Procedures）中作出明确规定。[…]