The Portable Ice Nucleation Experiment chamber (PINE): laboratory characterization and field test for its semi-automated ice-nucleating particle measurements in the Southern Great Plains

We present our laboratory and field test results of a newly developed commercial ice nucleation chamber, the so-called PINE, for its semi-autonomous measurements of atmospheric ice-nucleating particles (INPs). The PINE instrument is developed based on the design of the AIDA cloud chamber (Möhler et al., 2003) to promote long-term ambient INP measurements even at a remote location. Unique features of the PINE instrument include its plug-and-play feature (so it runs on a standard power outlet), susceptivity to the INP detection for 0.2 – 50K L^-1 STP in the ~0.7 – 220 mm size range (256 channels) with ~8 min time resolution, cryo-cooler-based automatic ramping-temperature operation, capability of quantifying INPs in different IN modes (e.g., immersion freezing and deposition mode at >-60 °C), and small particle loss through the system (~5% for <3 mm diameter particles). Our laboratory test results show that ammonium sulfate homogeneously freezes at -33 °C in PINE, which is comparable to the previous homogeneous freezing AIDA result (Hiranuma et al., 2016). Further, we observe immersion freezing of Snomax and illite NX at approx. -7 °C and -20 °C in PINE as seen by other online INP instruments (Wex et al., 2015; Hiranuma et al., 2015). These results validate the PINE’s capability to detect INPs in a wide temperature range, where “clear and significant research issues remain” (DeMott et al., 2011). Next, as for the first field test, we have performed a ground-based INP measurement with PINE at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) observatory, where long-term measurements provide statistical context (Marinescu et al., 2019). Briefly, we have successfully operated PINE via network for INP concentration measurements on a 24/7 basis for 45 consecutive days. Other findings from our lab characterization of PINE and first field deployment in the Southern Great Plains (e.g., comparison to other INP techniques) will be presented.

Acknowledgement: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (DE-SC0018979) – work packages 1-2 of Implications of Aerosol Physicochemical Properties Including Ice Nucleation at ARM Mega Sites for Improved Understanding of Microphysical Atmospheric Cloud Processes.

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