Journal of the Japanese Society of Snow and Ice
Online ISSN : 1883-6267
Print ISSN : 0373-1006
Volume 38, Issue 4
Displaying 1-6 of 6 articles from this issue
  • Masayuki NAKAGAWA, Kunio KAWADA, Toshio OKABE, Hiromu SHIMIZU, Eiji AK ...
    1976 Volume 38 Issue 4 Pages 157-164
    Published: December 30, 1976
    Released on J-STAGE: September 04, 2009
    JOURNAL FREE ACCESS
    Mt. Tateyama and its vicinity are in the region of heavy snowfall in Japan, but the snow cover of this mountainous area has not been investigated before. The purpose of the present work was to clarify the characteristics of snow cover on the Murodo flat (2450 m above sea level) in Mt. Tateyama. Vertical distributions of density, Kinoshita's hardness, temperature and texture of snow were observed once a month through 3 winters from 1972 to 1975.
    The Murodo flat was covered with snow from November to July and the water equivalent of snow cover reached a maximum of about 250 cm, in the last decade of April.
    From November to March a major portion of snow cover consisted of fine-grained compact snow. Maximum values of density and hardness were recorded in March as 0.51 g/cm3 and 25 kg/cm2, respectively. The relation between hardness R and density ρ is expressed roughly as R = 4004.6ρ kg/cm2. These values of hardness are about two times larger than those observed in Sapporo and Toikanbetsu of Hokkaido. The relation between density and compactive viscosity coefficient η derived from density distribution and accumulation rate is expressed by η =C exp (kρ) g·day/cm2. k is 20.2 for all snow covers, while C is in the range from 3.3 to 1.0, and the maximum and minimum correspond to the colder period (February) and warmer period (March) respectively.
    During the thawing season after April the average values of grain size and hardness of wet granular snow were about 2 mm in diameter and 5 kg/cm2 respectively and remained unchanged, while the density increased with time and reached 0.65 g/cm3 at the maximum early in July.
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  • Masao TAKEUCHI, Yoshibumi FUKUZAWA
    1976 Volume 38 Issue 4 Pages 165-170
    Published: December 30, 1976
    Released on J-STAGE: September 04, 2009
    JOURNAL FREE ACCESS
    Using transmissometers the study on the light attenuation and visibility in snow drift was made in the winter season of 1974 and 1975 in the Ishikari Plain, Hokkaido. The modulated visual light traversed through a path of 3 m long. Visibility observations by eye were carried out, using as targets 7 sheets of black boads installed at 150 m distant from observation point. The concentration of the snow particles was evaluated by the mass transportation of snow particles in drift traps at the same levels of the transmissometers.
    In general, the attenuation of light by airborne snow particles was explained by Mie's scattering theory. According to Mie's theory, it yields the scattering area ratio equal to 2. However, the size of airborne particles was large enough compared with the wavelength of light and the scattering area ratio of snow particles showed smaller than 1. Therefore, the light was attenuated not only by the scattering of snow particles but also mainly by their reflection.
    The relation between the concentration of airborne snow particles and the extinction coefficient of light was examined in the cases of drifting snow and falling snow. The result showed that when the extinction coefficient of light in drifting snow was about 5 times larger than that of falling snow under the condition of the same concentration of the particles, the particles of drifting snow are usually rounded and the size of them are smaller than the particles of falling snow. Therefore, it was considered that the extinction coefficient depended on the size and shape of the airborne snow particles.
    The visibilities in drifting snow and falling snow were measured under the condition of the same spatial mass concentration. The measurement showed that the visibility in drifting snow decreased 12 times less than that of falling snow and the visibility was determined by only the mass transportation of snow particles. Therefore, it was concluded that in the case of airborne particles having finite size such as snow particles was not explained by a homogeneous attenuation of light introduced by Koschmieder, but by the influence of visible particles themselves and their afterimages.
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  • Kohei TANAKA, Masatosi YAMAKI, Sigeru MASUDA
    1976 Volume 38 Issue 4 Pages 171-177
    Published: December 30, 1976
    Released on J-STAGE: September 04, 2009
    JOURNAL FREE ACCESS
    For hydroelectric power generation it is necessary to estimate the quantity of melt water flowing into the reservoir during the snow-thawing season. Up to this time the estimation was made with the snow gauge using radioactive isotope Co60, but this method required strict control over the preservation and handling of the radioactive substance. Therefore, a new method for snow detection, using photoelectric effect instead of Co60, was developed, and has been tested since 1973 in the area around Lake Towada.
    In the new method, cadmium sulfide photoelectric cells are placed in a transparent polymethyl-methacrylate pipe, and the depth of snow is estimated by the amplitide of light detected. The weight of the snow must be converted into the corresponding amount of water, and a little error may be caused by the conditions of snow. Nevertheless, this method has advantages in that the equipment is simpler, the reliability is higher, and it is free of troublesome maintenance or handling. The method can be applied to various types of robot snow gauge.
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  • Iwao TSUCHIYA
    1976 Volume 38 Issue 4 Pages 178-187
    Published: December 30, 1976
    Released on J-STAGE: September 04, 2009
    JOURNAL FREE ACCESS
    The abnomally heavy snowfalls in the Tohoku District, Japan during the 1973/74 winter season (November-March) produced some record-breaking snow depths at several meteorological stations, and unusually large amounts of snow in the Japan Sea side mountains were recognized by an airborne photogrametry which was carried out on 6 April 1974.
    An example of mean snow depth over a cirque of one kilometer in diameter was 17m, and many drift type snow covers reached 30-50m at niches of 1300-1900m above sea level on the eastern and southern slopes of Mt. Iide (Kitatamata-dake and Onishi-dake), Mt. Gassan and Mt. Chokai (40°N latitude).
    Some field surveys show the fact that the critical value of the one ablation season survival is about 30m at the above-mentioned places.
    A remnant drift type snow pack at the 1400m height on the southern slope of Mt. Chokai developed into a small niche type glacier after the heavy snowfalls of 1973/74 winter, and the glacier flowed at a rate of 20cm/day during the 1975 summer season.
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  • Daisuke FUKAZAWA
    1976 Volume 38 Issue 4 Pages 188-195
    Published: December 30, 1976
    Released on J-STAGE: January 22, 2010
    JOURNAL FREE ACCESS
    It is observed in Tochio City, Niigata District, that wet snow of about 0.1g/cm3 density on the roof of about 58-degree angle and roofed with galvanized long iron sheet breaks and slides down in small pieces when the snow on it is about 710 cm deep.
    The purpose of this report is to suggest an effective method of melting snow sliding down using river water.
    Arranged for the experiment were the following; a pool 1 m longer than eaves, 2 m wide and 0.6 m deep, a pipe pouring river water at 45-degree angle upward from holes at regular intervals, and a U-gutter along one brim of the pool to drain the snow broth.
    When river water of low temperature about 23°C is led into the pool which contains 176.1l/m2 water, at a rate of 0.8 l/m2 min, the snow of 0.36 g/cm3 density broken into pieces less than 10 cm diameter melts at a a rate of 2.41 kg/m2·h.
    This would be an effective method of melting the snow sliding down the roofs of houses in a heavy snow-region like the Hokuriku District, although sludge in the rive water to be used must be removed with a strainer for river waters today are badly polluted.
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  • [in Japanese], [in Japanese], [in Japanese]
    1976 Volume 38 Issue 4 Pages 196-197
    Published: December 30, 1976
    Released on J-STAGE: September 04, 2009
    JOURNAL FREE ACCESS
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