โ Scribed by B. F. J. Schonland; D. B. Hodges
No coin nor oath required. For personal study only.
An account is given of investigations on the location of sources of atmospherics in South Africa with visuallyโoperated cathodeโray directionโfinders, 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 ยฑ50 km. for storms at distances less than 750 km. At greater distances the accuracy decreases but is usually less than ยฑ100 km. at 1,500 km.
Of the land sources 76 per cent. were identified with thunderโclouds 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 dayโbyโday use of the system. A commentary follows by three officers of the Rhodesia Meteorological Service.
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