Shattering and particle interarrival times measured by optical array probes in ice clouds

AMS Citation:
Field, P. R., A. J. Heymsfield, and A. R. Bansemer, 2006: Shattering and particle interarrival times measured by optical array probes in ice clouds. Journal of Atmospheric and Oceanic Technology, 23, 1357-1371, doi:10.1175/JTECH1922.1.
Date:2006-10-01
Resource Type:article
Title:Shattering and particle interarrival times measured by optical array probes in ice clouds
Abstract: Optical array probes are one of the most important tools for determining the microphysical structure of clouds. It has been known for some time that the shattering of ice crystals on the housing of these probes can lead to incorrect measurements of particle size distributions and subsequently derived microphysical properties if the resulting spurious particles are not rejected. In this paper it is shown that the interarrival times of particles measured by these probes can be bimodal--the "cloud" probes are more affected than the "precipitation" probes. The long interarrival time mode represents real cloud structure while the short interarrival time mode results from fragments of shattered ice particles. It is demonstrated for the flights considered here that if the fragmented particles are filtered using an interarrival time threshold of 2 × 10⁻⁴ s in three of the four cases and 1 × 10⁻⁵ s in the other, then the measured total concentration can be affected by up to a factor of 4 in situations where large particles are present as determined by the mass-weighted mean size exceeding 1 mm, or the exponential slope parameter falling below 30 cm⁻¹. When the size distribution is narrow (mass weighted mean size <1 mm), ice water contents can be overestimated by 20%-30% for the cases presented here.
Subject(s):Aircraft observations, Icing
Peer Review:Refereed
Copyright Information:Copyright 2006 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work.
OpenSky citable URL: ark:/85065/d7cr5tm1
Publisher's Version: 10.1175/JTECH1922.1
Author(s):
  • P. Field - NCAR/UCAR
  • Andrew Heymsfield - NCAR/UCAR
  • Aaron Bansemer - NCAR/UCAR
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