AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Studying Coarse-Mode Aerosol Particles with Digital Holography from a UAV
MATTHEW BERG, Osku Kemppinen, Jesse Laning, Ryan Mersmann, Kansas State University
Abstract Number: 19 Working Group: Instrumentation and Methods
Abstract Digital holography (DH) has proven a powerful method to study aerosol particles, particularly the relatively large coarse-mode particles. Such particles are abundant in the atmosphere in agricultural, desert, and urban environments. The accurate characterization of these particles’ morphology is an important need in many scientific and applied contexts, especially to advance our understanding for how such aerosols influence the solar radiative forcing of the atmosphere. In the DH method, a particle is illuminated by an expanded laser beam and the interference pattern produced by unscattered and forward-scattered light from the particle is recorded on a sensor, i.e. a CCD. This interference pattern is the hologram, and from it, an image of the particle can be unambiguously rendered. Particles freely flowing in the atmosphere that are nominally 5 microns to several millimeters in size can be imaged this way. The relative simplicity of digital holography makes it an ideal candidate for a portable instrument for aerosol science. In this presentation, we present the design, construction, and application of such an instrument, the Holographic Aerosol-Particle Imager, or HAPI, which is mounted to an unmanned aerial vehicle (UAV). We will then discuss our initial use of HAPI to perform in situ observations of coarse-mode aerosol particles in the atmosphere.