Journal of the Meteorological Society of Japan. Ser. II

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We made some improvement in the point of bearing accuracy of the cathoderay direction-finders.
We equipped them at three observation stations several hundred kilometres apart in the Japan Islands, and made simultaneous direction observation. With the internal consistency of the bearing taken on atmospherics, the errors in direction-finding are found to be less than ±1 degree in almost all cases. So within the radius of 3000km, we can locate atmospherics with the sufficient accuracy to correlate with the results of the synoptic weather analysis. The results newly obtained in the summer and the autumn in 1951 are as follows:
1. Over the tropical and subtropical region of the Pacific, especially in summer and autumn, a large number of atmospherics are produced by disturbances due to easterly waves, and their percentage is comparable to that of atmospherics produced by heat-thunderstorms in Southeast Asia, for instance, Philippine Islands, Indo-China, etc..
2. When the long frontal line is produced over the Pacific by the outbreak of the polar continental air, its lower-latitude part often becomes stationary. In such a condition atmospherics are usually observed to be associated with this stationary front rather than with the other part of the front.
3. Over the lower-latitude region of the Pacific, a young cyclone often produces atmospherics, occasionally accompanying violent lightning discharges in its center area and its warm front area.
4. As for typhoons, atmospherics are observed in certain sectors of almost all typhoons in their both stages of immaturity and maturity. When they enter the stage of decay or dissipation by the effect of landing, no more atmospheri_??_s are observed in their active area.

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In the summer of 1952, the weather of Japan was bad, and the number of rainy days was greater than in the normal year. The cause of this weather seems to the author to be that the frontal zone stagnated along the south coasts of Japan and was closely related to the cut-off cold vortex in the upper air over Manchuria. In the lower layer of the cold vortex the pressure was lower than in the surrounding pressure fields, so that the divergence in the lower layer was weak and the dissipation of the cold vortex was also not remarkable. Moreover, it was found as a result of aerological analysis that the strong westerly (Jet Stream) was stagnant over the stationary front and that the inverse meridional circulation was situated around the Jet.

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