| Summary: | 1969-03-30 The observation of VLF emissions have been carried out at Showa Base (geomagnetic lat. 69.7°S) in the Antarctic from April 1967 to January 1968, using crossed loop antenna of triangle type and vertical antenna. In this paper, the occurrence of emissions and correlation with other geophysical phenomena are discussed. VLF emissions at 12KHz occurred almost from 1800 to 0100 UT. in all seasons except for December and January, and the duration of the emissions was 10-20 minutes on average. VLF emissions at 12KHz showed a complicated dependence on geomagnetic disturbances, auroral displays and radio absorptions in the ionosphere. On the other hand, VLF emissions at 750Hz were seldom to occurr in the daytime, and the duration of such emissions at 750Hz were longer than that at 12KHz. The upper frequency of such emissions was found to be about 4KHz utmost. departmental bulletin paper
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