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Direction‐finding of sources of atmospherics and South African Meteorology
Author(s) -
Schonland B. F. J.,
Hodges D. B.
Publication year - 1940
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49706628305
Subject(s) - thunderstorm , atmospherics , meteorology , storm , thunder , climatology , geography , lightning (connector) , environmental science , geology , power (physics) , physics , quantum mechanics
An account is given of investigations on the location of sources of atmospherics in South Africa with visually‐operated cathode‐ray direction‐finders, extending over a period of fifteen months and employing stations in Johannesburg, Durban and Bulawayo. The accuracy with which a thunderstorm source can be located by this method was found to be ±50 km. for storms at distances less than 750 km. At greater distances the accuracy decreases but is usually less than ±100 km. at 1,500 km. Of the land sources 76 per cent. were identified with thunder‐clouds and 18 per cent. with nimbus cloud. Sources over the oceans were found t o be closely associated with areas of low pressure, 89 per cent of such lows having associated sources. The progress of the lows could be followed by this method for several days. Their associated sources in the majority of cases lay in the warm sector from NNE. to ESE. of the centre of the low. The monthly and seasonal distributions of sources over the land agree with the distributions found by Brooks from thunderstorm data, except that over the Indian Ocean the number of atmospherics sources reaches a maximum in the winter. A discussion is given of the possibilities of the device in meteorology in Southern Africa and of difficulties encountered in the practical day‐by‐day use of the system. A commentary follows by three officers of the Rhodesia Meteorological Service.