Abstract. Atmospheric ice-nucleating particles (INP) play an important role in determining the phase of clouds, which affects their albedo and lifetime. A lack of data on the spatial and temporal variation of INPs around the globe limits our predictive capacity and understanding of clouds containing ice. Automated instrumentation that can robustly measure INP concentrations across the full range of tropospheric temperatures is needed in order to address this knowledge gap. In this study, we demonstrate the functionality and capacity of the new Portable Ice Nucleation Experiment (PINE) to study ice nucleation processes and to measure INP concentrations under conditions pertinent for mixed-phase clouds, with temperatures from about −10 °C to about −38 °C. PINE is a cloud expansion chamber which avoids frost formation on the cold walls, and thereby omits frost fragmentation and related background ice signals during the operation. The development, working principle, and treatment of data for the PINE instrument is discussed in detail. We present extensive laboratory based tests where PINE measurements were compared with those from the established AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber. The results show good agreement of PINE with AIDA for homogeneous freezing of pure water droplets and the immersion freezing activity of mineral aerosols. Results from a first field campaign conducted at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) observatory in Oklahoma, USA, from October 1 to November 14, 2019 with the latest PINE design (a commercially available PINE chamber) are also shown, demonstrating PINE’s ability to make automated field measurements of INP concentrations at high time resolution of about 8 minutes with continuous wall temperature scans between −5 and −35 °C. During this field campaign, PINE was continuously operated for 45 days in a fully automated and semi-autonomous way, demonstrating the capability of this new instrument to be also used for longer term field measurements and INP monitoring activities in observatories.

中文翻译：

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便携式冰成核实验PINE：一种用于实验室研究和冰成核颗粒的自动长期野外观察的新型在线仪器

摘要。大气冰核颗粒（INP）在确定云的相位方面起着重要作用，这会影响云的反照率和寿命。缺乏关于全球INP时空变化的数据，限制了我们的预测能力和对含冰云的理解。为了解决这一知识鸿沟，需要一种能够在整个对流层温度范围内稳健地测量INP浓度的自动化仪器。在这项研究中，我们演示了新的便携式冰核实验（PINE）的功能和能力，该研究用于研究冰核化过程并在与混合相云有关的条件下，在大约-10°C到大约-的温度下测量INP浓度。 38℃。PINE是一个云扩展室，可避免在冷壁上形成霜，从而在操作过程中省去了霜冻碎裂和相关的背景冰信号。详细讨论了PINE仪器的开发，工作原理和数据处理。我们提供了广泛的基于实验室的测试，其中将PINE测量值与已建立的AIDA（大气中的气溶胶相互作用和动力学）云室的测量值进行了比较。结果表明，PINE与AIDA在纯水滴的均匀冻结和矿物气溶胶的浸没冻结活性方面具有良好的一致性。还显示了2019年10月1日至11月14日在美国俄克拉荷马州的大气辐射测量（ARM）南部大平原（SGP）天文台进行的首次野外活动的结果，该运动采用了最新的PINE设计（可商购的PINE腔）。 ，展示了PINE能够在大约8分钟的高时间分辨率下对壁上的温度进行连续的-5至-35°C的扫描，从而对INP浓度进行自动现场测量的能力。在此野外活动期间，PINE以全自动和半自动化的方式连续运行了45天，证明了这种新仪器也可用于观测站的长期野外测量和INP监测活动。