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The Continuous Registraｔions of the Atmospheric Small-Ion Contents at Kakioka and Some Relations to the Meteorological Elements
Since the year 1951, the continuous registrations of the atmospheric small ions have been carried out using an Ebert-type ion counter and a Denshi-type long recorder. The former was made at this observatory and the later at the Yokogawa Electric Company.
Firstly the writer explains about the theory and the construction for the improvement of the recorder, whereby the leakage curves and calibrations of measuring system are automatically recorded every four hours. In the spring of 1953, it was completed at the Yokogawa Electric Company.
Next, the variations of small ions on both calm and disturbed days are described with respect to the observed data for the period 1951 to 1952. From the lack of enough observational data, we treat them qualitatively. The results are as follows;
1. On calm days, the annual mean values of small ion densities are 408 and 360 per unit volume of the air for positive and negative ions, respectively. The annual mean diurnal variation of small ion densities shows the double maximum type with two considerable sharp minima at early morning and evening，as generally observed at land stations. The seasonal changes of diurnal variation are indistinct.
2. The disturbance are frequently subsequent to ordinary rainfalls，snowfalls, thunderstorms, fogs, hazes and dust-storms etc.
During the ordinary rainfalls, the positive ions are not influenced by the changes of rainfall intensity, but the negative ions increase linearly. It seems that this increase is chiefly due to Lenard-effect.
On the occasions of the thunderstorms，both positive and negative ions increase remarkably.
We can not explain the increase in positive ions by Lenard-effect, and therefore we must consider some other possible causes.
On the foggy or hazy days, the small ion densities of both signs considerably decrease compared with the mean values of calm days. Particularly, these decreases on foggy days are more pronounced in winter than in summer. It seems that this seasonal difference is related to the mechanism of occurrence of those fogs. The decrease on hazy days may be explained with the increase of pollutions in the lower atmosphere.
Finally, we discussed about the problems on the construction of the ion-counter and the long-recorder, and on the methods of the observation.
Corrigenda is attached to this text.
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