Imamiti, S.
Magnetic Pulsations Observed by Induction Loops
Memoirs of Kakioka Magnetic Observatory, Vol. 7, No. 1, pp. 1-14, May, 1954
要旨
Studies of magnetic pulsatjons were made by many investigators. Among them Dr. T. Terada's investigation gives us most interest and many hints on the research of the phenomena. He used high sensitive variometers, namely, bifilars for H and D, and Watson type for Z, and the observed periods of pulsations were most frequent in the interval of 50s-60s. Notwithstanding high sensibility of his variometers, it was difficult to record the waves of shorter periods below 30 seconds, owing to the reason that the ampltudes of waves decrease with their periods, and moreover free period of an ordinary variometer is limited by the moment of inertia of the needle and consequently can not be much reduced.
Yoshimatsu, T.
The Local Characteristics of Earth－Currents
Memoirs of Kakioka Magnetic Observatory, Vol. 7, No. 1, pp. 15-26, May, 1954
要旨
In this chapter we dealt with their local characteristics as well as their world-wide natures of so-called universal earth-currents in respect to their spatial distributions and time variations. Since the very beginning of the history, many observations of this part of earth-currents have been carried out in various localities and in different epochs of the sunspot cycle. But owing to both defect of radical considerations of observational method and technique, and the complicated local natures of the earth's crust at the place where the observation is made, we are obliged yet to have little knowledge of thleir physical meanings, and even of the their morphological basic facts as a world-wide phenomena. Therefore, in order to promote quickly this slow progress, as it holds good for the cases of other branches of science developed recent1y, it is strongly desired to obsererve them by using more modern techniques and apparatus at more well distributed statjons al1 over the world. .And then should be estabiished their phenomenistic backbone of this branch of science. Unfortunately, it is a fact that even this self-evident requirement was not so easily realized. It is grateful, however, to have had recently many valuable material at several places in the world.
湯村哲男
磁気嵐急始部変化について
地磁気観測所要報, 第7巻, 第1号, pp. 27-48, 1954年5月
要旨
In order to clarify some points of the subject, a statistical investigation on the sudden commencement of geomagnetic storms is made in this paper, though similar investigations have been carried out morphologically or theoretically by many authors.
The results obtained are as follows;
(1) The geomagnetic latitudinal distribution of the direction angles of horizontal vector of the sudden commencement, reckoned from the magnetic meridian, is approximately symmetrical with respect to the magnetic equator (Fig,2).
(2) The hourly distribution of the direction angles depend upon the local time of each observatory, and the values between 12h and 24h L.T. are concentrated around nearly 0°, that is to say, around the direction of the magnetic north, but during 6h to 12h L.T. they fluctuate with a large amplitude on both sides of their mean values in high latitudes (Fig.3).
On the other hand, the inverted SC's are appearing more frequently in the same interval, 6h to 12h L.T., in high magnetic latitude.
(3) A conventional conception that the horizontal vector of SO. are nearly pointing to the geomagnetic north is roughly right in middle or low magnetic latitudes, but not so in high latitudes.
(4) The distribution of the magnitudes of horizontal vectors for the geomagnetic latitude, which are expressed by the ratios of the values at various observatories to those observed simultaneously at Huanaayo, shows a result similar to that already known, namely the W-type distribution with symmetry to the magnetic equator. The curve has a minimum value of about 0.4 near the magnetic latitude 30°, and increases from the minimum point monotonous1y with the increasing magnetic latitude (Fig.4).
By this method, however, the values of each observatory fluctuate in so wide a range around the mean value that the above result is not so accurate.
(5) The magnitude ratios of horizontal vectors at various observatories to those at Huancayo are distributed on a regular curve with the period of one day, where the minimum point of the curve appears around noon at Huancyo (Fig.5).
This result may be due to the large amplitude of SC. in the daytime at Huancayo compared with those at other observatories.
How can we interprete the fact the variation of the sudden commencement, which has been considered to be originated from without the earth's atmosphere, show the above-mentioned daily variation due to the sun's altitude?
(6) Next, it is tried to subtract the apparent influence of the sun's ultra violet light from the result given in (4). The result gives no essential difference, but will be useful for more reasonable interpretation of the geomagnetic latitudinal distribution of SC; tbe magnitudes obtained in this way are just half of that at ±30° and l.5 times as large as that at ±60° (Fig.7).
However. We must in future determine the distribution for each season by using more data.
(7) The ratio of the amplitude of the vertical component to that of the horizontal vector shows a regular distribution in respect to the geomagnetic latitude (Fig.8).
This distribution curve is approximately symmetrical to the magnetic equator, with the maxima at about ±20°-±30°(positive regions) and the minima at about +15° and -35° (negative regions) .
It may be difficult to interprete such distribution by Chapman's theory of the magnetic storm.
柳原一夫
柿岡における地電流の擾乱日変化
地磁気観測所要報, 第7巻, 第1号, pp. 49-54, 1954年5月
要旨
The daily variation on quiet days, Sq, of the earth-currents at Kakioka for a 11-year period, 1934-1944, were formerly summarized in the Report of the Kakioka Magmetic Observatory. In the present paper, some characteristics of the disturbance daily variation, SD , of the earth-currents for the same period are given, as follows:
ⅰ) In the mean values SD and SA=S-Sq computed for the whole period, there is remarkable secondary minimum at 10h (Fig.1). The 'two values are coincident each other in phase, but the amplitude of the latter is about 40% of the former.
ⅱ) The change of the amplitude of SA (or SD) with seasons and years is remarkable in the diurnal component, but not clear in the semi-diurnal component (Figs.2 and 4). The appearance of a secondary minimum at l0h may be uncertain at equinox and sunspot-maximum year, because of the predominant diurnal component in the same period.
ⅲ) Our result in (ⅰ) differs from the well-known conclusion that the SD in earth-currents is materially a single wave (diurnal one) as in earth-magnetism. Then the mean SA at Tuson for the period 1932-1942 is computed (Fig.3). As it is seen in the figure, especially in the vector diagram, departures from the diurnal variation in the hours 12h-18h and 3h－7h are remarkable. Again the result at Watheroo (after Rooney) shows some departures from diurnal variation.
Generally speaking the appearance of the secondary minimum is not a local phenomenon at Kakioka, but seems to be of world-wide character. It may be related to the disturbance short period or duration.
菊池繁雄
柿岡における大気小イオン数の連続自記観測並に気象要素との関係
地磁気観測所要報, 第7巻, 第1号, pp. 55-74, 1954年5月
長嶺亘
海霧の空中電気調査
地磁気観測所要報, 第7巻, 第1号, pp. 75-78, 1954年5月
Kakioka Magnetic Observatory
Geomagnetic Indices K and C for 1953 at Kakioka
Memoirs of Kakioka Magnetic Observatory, Vol. 7, No. 1, pp. 79-81, May, 1954
