Resurgence in Ice Nuclei Measurement Research

Abstract

Measuring systems for atmospheric ice nuclei are undergoing development anew and are beginning to meet the needs for studies of aerosol effects on ice-containing clouds. U nderstanding and predicting the formation of ice in clouds and its possible relation to the changing state of atmospheric composition (aerosols and gas phase) remain enigmatic. Such knowledge and capabilities are critical to quantifying the role of aerosols and their changing compositions on clouds, precipitation, and climate (Denman et al. 2007;Levin and Cotton 2009). This challenge is a major motivation for renewed attempts to measure ice nucleation processes in general, and to design and deploy new portable systems for measuring ice nuclei (IN), the particles that are considered the only means for initiation of the ice phase at temperatures warmer than about −36°C in the atmosphere. The fundamental desire to understand ice nucleation remains the same as when such research began in earnest more than 60 yr ago. The search to identify atmospheric ice nuclei lapsed during the 1970s-80s

A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of 17 ice nucleation measurement techniques

“…This reproducibility verified the performance of the IMCA-ZINC combination, which was not tested during ICIS-2007(DeMott et al, 2011, perhaps due to the similarity in the experimental conditions (i.e., particle generation) to the other two methods. We also note that the residence time in ZINC is about a factor of 3 longer than that in PINC.…”

“…The operation principle of this type of chamber does not involve water vapor diffusion from the ice walls, as in CFDC, but water vapor is available for ice growth from the humidified air within the chamber flow. This leads to an upper limit on INP concentrations that are observable with this methodology (DeMott et al, 2011). A flow tube (e.g., Leipzig Aerosol Cloud Interaction Simulator or LACIS, Hartmann et al, 2011) has also been developed in which a humidified stream containing aerosol particles is first cooled to activate droplets on the particles, which upon further cooling may then freeze.…”

“…Since the 1960s, four international workshops have been organized to compare the performance of IN measuring instruments that were emerging or available at the time (DeMott et al, 2011). In particular, effort was made during the fourth international ice nucleation workshop in 2007 (ICIS-2007) to assemble a total of nine laboratory and field IN instruments at the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) facility and compare them using identical test dust samples (e.g., Arizona Test Dust, or ATD, and Saharan dust) over similar thermodynamic conditions.…”

“…a high number of growing ice crystals (DeMott et al, 2011). A constant total concentration of particles continuously passing through the chamber was maintained at 1.07 ± 0.17 cm −3 (average ± standard deviation).…”

Single Particle Measurements of the Optical Properties of Small Ice Crystals and Heterogeneous Ice Nuclei

“…The CFDC is an instrument typically used to measure the ice nucleation potential of aerosol (Rogers et al 2001a,b;Prenni et al 2007Prenni et al , 2008DeMott et al 2011). The work conducted in this study is unique as this is the first time a CASPOL instrument has been coupled with a CFDC.…”