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  • Author or Editor: J. Hallett x
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B. A. Gardiner
and
J. Hallett

Abstract

Airborne measurements of cloud liquid water content derived from a formvar replicator, a Johnson-Williams probe and a forward scattering spectrometer probe (FSSP) are compared. These show that in the presence of ice crystals the FSSP droplet spectra may be artificially enhanced. Typically the ice produces a flat distribution superimposed on the actual droplet distribution. The concentrations measured by the FSSP in the presence of ice are found to be 2–3 orders of magnitude greater than the actual ice concentrations as measured by the formvar replicator and a 2D-C probe. Possible explanations for the abnormal behavior of the FSSP in the presence of ice particles are discussed.

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C. P. R. Saunders
,
R. L. Pitter
,
B. A. Gardiner
, and
J. Hallett

Abstract

A system is described for measurement and analysis of precipitation particle charge from an aircraft in the highly variable and harsh environment of a convective cloud. A compromise, practical instrument design enables particle charge and sign to be measured with concentrations up to 5 L−1. The system employs two induction rings in series; it is de-iced both on the electrostatic shield and internally. New techniques are described which enable rapid analysis of sequential charge data over a penetration period of 55 s, with rejection of spurious data pulses resulting from particle impaction.

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