A Continuous Flow Microfluidic Based Instrument for Measuring Ice Nucleating Particles

ETHAN EMERSON, Kate Patterson, Matt Freer, Ben Swanson, Andrew Metcalf, Russell Perkins, Jessie Creamean, Paul DeMott, Gavin McMeeking, Handix Scientific

     Abstract Number: 310
     Working Group: Instrumentation and Methods

Abstract
Ice nucleating particles (INP) affect climate and precipitation by impacting the formation of ice in clouds. Existing online or continuous measurements require large and power intensive instruments, which limits the number and location of high temporal resolution and long duration INP observations. We present a new approach for measuring INP in a liquid sample continuously using microfluidics. This approach allows for online analysis using a particle-into-liquid sampler (e.g., Liquid Spot Sampler) or offline sample analysis of filter samples extracted into liquid. The Continuously Operating System for Microfluidic Ice Counting (COSMIC) is capable of measuring INP concentrations as a function of temperature, ranging from approximately 0 to -30 C with minimal user intervention. The measurement system fits in a standard 19-inch rack and occupies 9 inches of vertical space. The current prototype uses a standard laboratory chiller operating on standard AC power, making the system more flexible than current online measurement techniques. We present instrument characterization, including measurements of freezing spectra of previously characterized INP, including minerals, dusts, and biological particles, as well as field samples. Results are compared to measurements from the Colorado State University Ice Spectrometer. We will also discuss the ongoing work to couple COSMIC to a particle-into-liquid sampling system that provides continuous measurements of INP in air.