Implementing the Portable Ice Nucleation Experiment (PINE) chamber for measuring atmospheric ice-nucleating particles at multiple Atmospheric Radiation Measurement (ARM) observatories

Description

We present our field test results of the newly developed Portable Ice Nucleation Experiment (PINE) chamber for its semi-autonomous measurements of atmospheric ice-nucleating particles (INPs). The PINE instrument is developed based on the design of the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud chamber (Möhler et al., 2003, Atmos. Chem. Phys.) 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 20A power outlet), susceptivity to the INP detection for 0.2 – 50K L^-1 STP of particles (aerosol, cloud droplets and ice crystals) in the ~0.7 – 220 mm size range (256 channels) with a ~8 min time resolution, liquid-free cryo-cooler-based automatic ramping-temperature operation, capability of quantifying INPs in different ice nucleation modes (e.g., immersion freezing and deposition nucleation 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, Atmos. Meas. Tech.). Further, we observe immersion freezing of Snomax and illite NX at approx. -7 °C and -20 °C, respectively, in PINE as seen by other online INP instruments (Wex et al., 2015, Atmos. Chem. Phys.; Hiranuma et al., 2015, Atmos. Chem. Phys.). These results validate PINE’s capability to detect INPs in a wide temperature range, where “clear and significant research issues remain” (DeMott et al., 2011, Bull. Amer. Meteorol. Soc.). Next, as for the first field test, we have performed a ground-based INP measurement with PINE at the ARM SGP (Southern Great Plains) observatory, where long-term measurements provide statistical context (Marinescu et al., 2019, Atmos. Chem. Phys.). Briefly, we have successfully operated PINE via a network for INP concentration measurements in various ambient conditions on a 24/7 basis for 45 consecutive days. Our first SGP INP results will be presented. Other meaningful findings from our field PINE deployment in the ENA (Eastern North Atlantic) site will also be presented.

Acknowledgement: I acknowledge the support from many individuals at the ARM stations (including but not limited to) Chris Martin, Mark Smith, Ken Teske, John Schatz, Michael Ritsche, Jody Martin, James Martin, George Sawyer, David Swank, Tim Grove, Rod Soper and all admin people at the stations.