Atmospheric Measurement Techniques Discussions www.atmos-meas-tech-discuss.net 1867-8610 2 2 2009 10.5194/amtd-2-659-2009 http://www.atmos-meas-tech-discuss.net/2/659/2009/ http://www.atmos-meas-tech-discuss.net/2/659/2009/amtd-2-659-2009.html http://www.atmos-meas-tech-discuss.net/2/659/2009/amtd-2-659-2009.pdf 659 688 2009-03-03 Cloud particle size distributions measured with an airborne digital in-line holographic instrument J. P. Fugal fugal@ucar.edu R. A. Shaw Physics Dept., Michigan Technological University, Houghton, MI 49931, USA now at: National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307, USA Holographic data from the prototype airborne digital holographic instrument HOLODEC (Holographic Detector for Clouds), taken during test flights are digitally reconstructed to obtain the size (equivalent diameters in the range 23 to 1000 μm), three-dimensional position, and two-dimensional profile of ice particles and then ice particle size distributions and number densities are calculated using an automated algorithm with minimal user intervention. The holographic method offers the advantages of a well-defined sample volume size that is not dependent on particle size or airspeed, and offers a unique method of detecting shattered particles. 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