Journal of the Oceanographical Society of Japan
Online ISSN : 2186-3113
Print ISSN : 0029-8131
ISSN-L : 0029-8131
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Volume 20, Issue 2
Displaying 1-5 of 5 articles from this issue
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  • Topography and Sediment in the Southern Part of Japan Trench
    Akio MOGI, Takahiro SATO
    1964 Volume 20 Issue 2 Pages 51-56
    Published: June 30, 1964
    Released on J-STAGE: June 17, 2011
    DOIhttps://doi.org/10.5928/kaiyou1942.20.51
    JOURNAL FREE ACCESS
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    In the twice surveyings of July and September of 1959, Takuyo a surveying vessel of Hydrographic Office found out the Second Kashima Seamount from the Japan Trench. Severall transverse profiles from the east coast of Japan to the Japan Trench, show three terraces on. the continental slope off the east coast of Japan. In these terraces, the flat plains at 1, 000 to 2, 000 meters in depth are very wide and continuous on the sea bottom off the east coast of Japan. Transverse profiles of the Japan Trench are commonly asymmetrical and bottoms of the trench are flat. By the operation in latter cruise, short core was obtained, which was so-called radiolarian ooze of deep sea type.
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  • Deformation of Temporal Pattern of Orbital Wave Velocity and Sediment Transport in Shoaling Water, in Breaker Zone and on Foreshore
    Yutaka NAGATA
    1964 Volume 20 Issue 2 Pages 57-70
    Published: June 30, 1964
    Released on J-STAGE: June 17, 2011
    DOIhttps://doi.org/10.5928/kaiyou1942.20.57
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    The horizontal velocities of orbital wave motion were measured by electromagnetic current meters. The deformations of temporal patterns of orbital wave velocity are discussed in respect to two typical beaches of gentle slope and steep slope. The results are examined together with the data on suspended sediments. A simple model on the mechanism of the balance of sediment transport in a cross-section perpendicular t o shoreline is proposed and an explanation is given to account for the occurrence of coarse sands along steeply sloping beach and fine sands along gradually sloping beach.
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  • An Electromagnetic Current Meter
    Yutaka NAGATA
    1964 Volume 20 Issue 2 Pages 71-80
    Published: June 30, 1964
    Released on J-STAGE: June 17, 2011
    DOIhttps://doi.org/10.5928/kaiyou1942.20.71
    JOURNAL FREE ACCESS
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    We have developed two types of electromagnetic current meters, one employing permanent magnet (P-type) and the other, using electromagnet (E-type). The P-type current meter is easy to operate. It is suitable for the measurements of rapidly varying flows such as orbital wave velocities. However, as the signals are contaminated with polarization potentials of the electrodes, the accuracy of the measurement is limited especially for steady flows. On the other hand, stable and accurate recording of flows is possible with the E-type current meter. Here we get the output of the alternating electromotive force which is amplitude-modulated in proportion to the flow speed. Since the polarization potentials vary slowly with time, only the A.C. components of the current meter output is amplified by the A.C. amplifier. This signal is demodulated and we obtain the final output signal.
    The directional response characteristics of the current meter depend on the shape of the meter. We examined several shapes in order to make the directional characteristic curve be of cosine shape.
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  • Oceanographic Investigation of Radioactive Contamination of Sea Water at the Mid Pacific Area
    Masaru SHIOZAKI, Yoshiro SETO, Ryoji HIGANO
    1964 Volume 20 Issue 2 Pages 81-88
    Published: June 30, 1964
    Released on J-STAGE: June 17, 2011
    DOIhttps://doi.org/10.5928/kaiyou1942.20.81
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    The nuclide analysis of sea water collected near Christmas Island has been carried out. The analyzed nuclides are Sr-90, Cs-137 and Ce-144. There are differences in the concentrations of these three nuclides among the South Equatorial Current, the Equatorial Counter Current and the North Equatorial Current areas. There are also differences in the aspects of vertical distribution of radioactivities between Sr-90 and Ce-144. These differences may be due to the chemical and biological stabilities of both nuclides in sea water.
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  • Relation of Silicate Concentration to Dissolved Oxygen Amount in Sea Water Collected in the Northern, Frontal Region of Kuroshio
    Yoshio SUGIURA, Suphachai CHAITIAMVONG
    1964 Volume 20 Issue 2 Pages 89-92
    Published: June 30, 1964
    Released on J-STAGE: June 17, 2011
    DOIhttps://doi.org/10.5928/kaiyou1942.20.89
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    Silicate was determined by a silicomolybdic acid method aboard the observation ship. The particular relation of silicate to apparent oxygen utilization (A. O. U.) is clarified, which is remarkably different from the relation of phosphate to A. O. U. In this connection, it is infered that some part of silicate is dissolved into water by non-biochemical process.
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