宇宙線と颱風

新氣象要素としての宇宙線, IV

抄録

Using the results of cosmic-ray observations made at the Institute of Physical and Chemical Research in Tokyo, cosmic-ray intensities in different quadrants of typhoon are studied. The conclusions stated below are based on the examination of a number of similar examples which are not reproduced here.
As regards the upper air structure in the north quadrant of typhoon, the nature is quite the same with that of an ordinary extratropical cyclone. For example, a tropical disturbance appeared on September 11, 1939, in the southern sea far away from Japan proper. The center crossed the sea to the southeast of Tokyo on September 23. Later, on October 2, 1939, a typhoon crossed the sea to the southeast of Tokyo, following a path quite similar to the former one. The tracks are shown in Fig. 1, in which the thick full lines represent the observed paths of two typhoons and the attached marks give the morning positions of the centres respectively. In Fig. 2 are given the observed cosmic-ray intensities in Tokyo during the passages of typhoons. The materials observed show that the cosmic-ray intensities are fairly constant during the period.In the south quadrant of a typhoon fresh tropical air advances rapidly to the north under the influence of the typhoon. On September 11, 1937, a typhoon crossed the Sea of Japan northeastwards, the track being shown in Fig. 3. The cosmic-ray materials on that day illustrated in Fig. 4 show that the intensity decreased beyond doubt during the passage of the typhoon, though the intensities at the stage of full violence of typhoon were unfortunately uncertain.
Comparing Fig. 2 with Fig. 4, the cosmic-ray variations in the typhoon area are quite in accord with the facts which are obtained by aerological observations in the typhoon area⁽¹⁾; and such cosmic-ray variations can be safely attributed to the “Temperature Effects”.
The distributions of cosmic-ray intensities in cyclonic and anticyclonic areas are shown in Figs. 5 and 6 in their revised forms after elliminating the seasonal variation of the paths of barometric centres.