Atmospheric electricity during disturbed weather

Abstract

From October, 1942, to May, 1946, a special investigation of, atmospheric electricity during disturbed weather was undertaken at Kew Observatory, England, with special reference to the electricity carried on rain and snow. The results obtained have been discussed in detail in a paper which is to be published as Geophysical Memoir No. 84 by the London Meteorological Office. Owing to shortage of paper and other difficulties resulting from the war it may be some considerable time before the Memoir is printed and distributed. The Director of the Meteorological Office has therefore approved of the following summary of the conclusions reached in the work being made available in advance of the publication of the Memoir.

Charge transfer by precipitation between thundercloud and ground

“…For each case of polarity they indicated that the charges carried by the precipitation at the Earth surthce have the same sign as that of the space charge in the subcloud layer through which the raindrops have fallen. As given by Simpson [1949], they observed the nfirror image relation between the electric field and the rain current density', that is, the field is upward when the precipitation current carries dox•n positive charges. R,st and Moore [1974] and at the ground.…”

The Mirror Image Relation in the Vertical Distributions of Electric Field and Precipitation Charge in Winter Thunderclouds

“…According to this mechanism, the electrification of precipitation particles is a result of the electric field. However it is seen in a figure presented by Simpson (1949) that the change in the sign of precipitation current occurred earlier than that of electric field. Namely, the result seems to have preceded the cause.…”

“…About fourty years ago, Noto (1939) found that the sign of charge on raindrops and snowflakes was opposite to that of electric field at the ground, and Simpson (1949) reported that the sign of precipitation current changed inversely against that of the electric field. The sign of electric field is defined to be positive when a positive charge exists above the ground, and that of precipitation current is defined as positive when positively charged raindrops fall.…”

Surface Electric Field of "Wave Pattern" and Radar Echo Structure of Middle-Level Precipitating Clouds

“…Many investigators have reported various patterns of changes in the surface electric field during rainfall (for example, Simpson, 1949;Sivaramakrishnan, 1953;Whitlock and Chalmers , 1956;Magono and Orikasa, 1960;Huzita and Ogawa, 1976). These patterns can be roughly classified into two types.…”