The Balloon-Borne Particle Size, Image, and Velocity (PASIV) Probe Used in the Deep Convective Clouds and Chemistry Experiment

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Sean Waugh (University of Oklahoma/National Severe Storms Laboratory)
Conrad Ziegler (National Severe Storms Laboratory)
Don MacGorman (National Severe Storms Laboratory)
Doug Kennedy (National Severe Storms Laboratory)
Sherman Fredrickson (National Severe Storms Laboratory)

During May-June 2012, a team from the National Severe Storms Laboratory flew a balloon-borne particle imager called the PASIV into severe thunderstorms during the Deep Convective Clouds and Chemistry (DC3) experiment. The objective of the PASIV was to measure drop-size distributions, particle concentrations, and particle habits in a vertical profile through severe weather on a spatial and temporal resolution not achievable by conventional disdrometers. Furthermore, being balloon-born, the PASIV is capable of traversing regions of severe weather generally deemed too hazardous for traditional aircraft flight. The PASIV was accompanied by a Vaisala RS92-SGP radiosonde to measure location and standard thermodynamic variables and an electric field meter (EFM) to measure the vector electric field to provide context for the microphysics information collected. The PASIV probe consists of an HD video camcorder (Panasonic Model HDC-SD9) and a PARSIVEL laser disdrometers to provide the size, shape, phase, velocity, and number density of sample particles.

Our goal in flying PASIV was to provide the vertical distribution of size spectra for various types of particles for use in verifying the microphysics modules of numerical cloud models and the hydrometeor classification schemes of polarimetric radars, as well as to help improve the understanding of storm electrification processes. This paper will present an overview of the PASIV and data collected during a multicell storm cluster sampled during the DC3 experiment, including particle distributions for various particles relative to the electric field structure of the case.

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