Publication Date:
2022-05-26
Description:
A short critical review of possible methods for the measurement of the size of fog particles is
presented. It is concluded that the only suitable method of obtaining the distribution of drop sizes
present in a given fog consists in the microscopic measurement of large numbers of drops which
have been collected on a properly surfaced slide. A method for surfacing microscope slides with a
thin, uniform layer of petroleum grease is described. The important problem of obtaining a representative
sample of drops on a slide is next considered. Experimental results indicate that slides
no larger than 5 mm square will collect satisfactory samples if exposed facing the wind. Larger
slides are found to discriminate against the smaller drops. Special fog microscopes which have been
constructed for observing droplet samples are described, and typical results obtained in natural
fogs are presented. Although forty sets of data have been procured in sixteen different fogs, it has
not been possible to correlate the drop size data with any of the accompanying meteorological
conditions. There is no evidence of mass grouping, such as Köhler observed in clouds; however,
definite conclusions cannot be drawn from such a relatively small amount of data. The usefulness of fog water data is indicated and possible methods of procuring them are
reviewed. An investigation of the sampling problem encountered in the operation of most fog
measuring instruments is described. The method of avoiding sampling diffculties in a new fog
water instrument is explained and the constructional features and operation of the apparatus are
discussed.
Keywords:
Fog
;
Clouds
Repository Name:
Woods Hole Open Access Server
Type:
Book
Format:
3773038 bytes
Format:
application/pdf
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