Statistical investigations have shown that the number of thundercloud occurrences in the surrounding district of Volcano Asama has a remarkable inverse relation to the eruptive activity of the volcano during the summer season, especially in August. The inverse relation between them has been analysed under the time scale of a month in the previous report. Here, the relation is analysed in the time scale of day. It is found that the thundercloud occurrences are remarkably decreased for a day following the eruption of Asama.
It became clear that during the rainy season the region considered here is a source region of kinetic energy, and a large surplus of kinetic energy is exported across the boundary to the central Pacific. The release of kinetic energy is directly associated with the processes of sinking of cold air over the northern Japan Sea and of ascending of warm air in the region where subtropical jet stream prevails. As for the available potential energy, however, the region in question is a sink region. The import of available potential energy is mainly accomplished by two prevailing wind systems, i.e., SW- and SE- monsoon.
Radar- and meso-analyses on the barometric oscillations are made which occurred on the stationary fronts near the Kyushu district, Japan. As a result, it is revealed that they are caused by the shearing waves on the internal boundary of the atmosphere, and that the precipitation area corresponds to a crest and the clear sky area to a trough. A theoretical consideration seems also to support the statements.
An absolute standard barometer recently installed at the Japan Meteorological Agency, Tokyo, is . described. It is essentially a syphon barometer made of glass tube 30mm in internal diameter. The two mercury meniscuses can be equally formed by operating the mercury reservoir hydrostatically connected with the mercury column. The vacuum in the space above the mercury is measured by a Geisler tube. The barometric height is read measuring the position difference of two meniscuses by means of a standard scale and a cathetometer. The average temperature of the mercury column is determined from the readings of two thermometers hung on the mercury column. It was intended that the accuracy of a single reading of the barometer should be in the order of 0.OlmmHg, while in practice, it is found that the standard deviation of errors included in the observed values is 0.03mmHg. The result of its comparison with the present DMA's standard barometer gives that the mean correction of the JMA's standard in relation to the new absolute standard barometer is -0.20mmHg.