Characterization of a new Portable Ice Nucleation Experiment chamber
(PINE) and first field deployment in the Southern Great Plains
Abstract
We present our first laboratory calibration and field results of a newly
developed commercial ice nucleation chamber, the so-called PINE. The
PINE instrument is developed based on the design of the AIDA cloud
chamber (Möhler et al., 2003) to advance online atmospheric ice
nucleation research. A unique aspect of the PINE chamber includes its
plug-and-play feature (so it runs on a standard power outlet),
autonomous cryo-cooler-based temperature-ramping operation, capability
of quantifying INPs in different IN modes (e.g., immersion freezing and
deposition mode at >-60 °C), small particle loss through
the system (~5% for <5 m diameter
particles), and sensitive optical particle detection of INP
concentration (≤0.1 L-1 at T > -15 °C), promising
stand-alone operation at remote locations. To date, the PINE chamber has
been calibrated using test aerosol particles with known properties
(e.g., illite NX). Briefly, test particles were exposed to ice
supersaturation conditions, where a mixture of droplets and ice crystals
were formed during the ‘expansion’ experiment. A comparison of our
calibration test results to other techniques will be presented. Further,
the PINE instrument has been tested in field campaigns in the Southern
Great Plains. With a turnover time of ~6 minutes, PINE
ran continuously and scanned at different temperature intervals to
assess different INP episodes. We made sure to assess at least a few
degrees of common temperature interval in a series of scan. Our first
field results will be shown. Our results suggest that using this
autonomous instrument may be critical to minimize error sources in
high-temperature and supermicron INP research. 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.
References: • DeMott, P. J. et al. Resurgence in ice nuclei measurement
research. Bull. Amer. Meteorol. Soc. 92, 1623,
doi:10.1175/bams-d-10-3119.1 (2011). • Möhler, O. et al. Experimental
investigation of homogeneous freezing of sulphuric acid particles in the
aerosol chamber AIDA. Atmos. Chem. Phys. 3, 211-223 (2003).