Abstract
Directional observations of the radio-atmospheric disturbance were commenced in July 1926. A preliminary account on the apparent direction of arrival of atmospherics at Tôkyô has been published in this Journal in April 1927. The observations are thenceforth being continued and from the results so far obtained, the following conclusions may be arrived at relating to the sources of atmospherics in Japan, with special reference to their relation with the meteorological environment.
(1) The apparent direction of arrival of most clicks is often very definite and can easily be determined; still in no less cases the direction is almost indefinite, i. e. almost equal number of atmospherics arrives from every direction.
(2) It is also often the case, especially in summer and autumn when the atmospherics are most prevalent, that there are more than one direction, at which the number of atmospherics shows a maximum.
(3) A permanent source of atmospherics seems to exist at the bearing 300°to 330° from Tôkyô; in all seasons except winter many atmospherics seem to arrive from these directions.
(4) Besides this permanent one, sources of atmospherics are produced in and in the vicinity of Japan, according to the meteorogical environment. Several examples are given, showing thunderstorms and lines of discontinuity as the sources of disturbances.
(5) There are still evidences to show that many atmospherics come from the S-W direction, presumably from the troplcs. These disturbances can easily be distinguished from the short-range ones, when in winter the latter are stamped out.
Full details will shortly be published in English in the Report of the Aeronautical Research Institute, Tôkyô Imperial University.
