Abstract. Capturing the vertical profiles and horizontal variations of atmospheric aerosols often requires accurate airborne measurements. With the advantage of avoiding health and safety concerns related to the use of butanol or other chemicals, a water-based condensation particle counter (wCPC) has emerged to provide measurements under various environments. However, the airborne deployment of wCPC is relatively rare due to the lack of characterization of wCPC performance. This study investigates the performance of a commercial "versatile" water CPC (vWCPC Model 3789, TSI) under low-pressure conditions. The effect of conditioner temperature on wCPC performance at low pressure is examined through numerical simulation and laboratory experiments. We show that the default instrument temperature setting of 30 °C for the conditioner is not suitable for airborne measurement and that the optimal conditioner temperature for low-pressure operation is 27 °C. Additionally, we show that insufficient droplet growth becomes more significant under the low-pressure operation. The variation in the chemical composition can contribute up to 20 % uncertainty in the counting efficiency of the wCPC, but this variation is independent of pressure.

中文翻译：

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用于大气空气传播研究的多功能水凝结粒子计数器的模拟辅助表征

摘要。捕捉大气气溶胶的垂直剖面和水平变化通常需要准确的空中测量。水基冷凝粒子计数器 (wCPC) 具有避免使用丁醇或其他化学品相关的健康和安全问题的优势，可在各种环境下进行测量。然而，由于缺乏 wCPC 性能的表征，wCPC 的机载部署相对较少。本研究调查了商业“多功能”水 CPC（vWCPC 型号 3789，TSI）在低压条件下的性能。通过数值模拟和实验室实验研究了调节剂温度对低压下 wCPC 性能的影响。我们表明，调节器的默认仪器温度设置为 30 °C，不适用于空气测量，而低压操作的最佳调节器温度为 27 °C。此外，我们表明在低压操作下液滴生长不足变得更加明显。化学成分的变化会对 wCPC 的计数效率造成高达 20% 的不确定性，但这种变化与压力无关。