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Volume 45 (1983)
- Issue 4 Pages 161-
- Issue 3 Pages 119-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 45, Issue 4
Displaying 1-6 of 6 articles from this issue
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Hiroshi NISHIMURA, Shigeo SUIZU, Kouichi NISHIMURA1983 Volume 45 Issue 4 Pages 161-168
Published: December 30, 1983
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSIn the summer of 1977, surface ablation and relevant meteorological parameters were measured on the bare ice and moraine-covered ice of the Biafo Glacier in the Karakorum. The ablation rate of the bare ice was 6.8 cm/d in water equivalent while it was 2.1 cm/d for the 6 cm thick moraine-covered ice. The total amount of ablation had a close correlation with the positive degree-days of air temperature. Ablation experiments on ice with different moraine cover from 2 to 18 cm showed a decrease in ablation with an increase of moraine thickness. This result was similar to that which was obtained in the Hidden Valley in Nepal Himalaya, but slightly different from results obtained in Europe and Japan. Ablation of bare ice under two plastic sheets, having 44% and 94% in transmittivities of solar radiation, showed that the ablation was due mainly to the solar radiation; this was confirmed by a heat balance calculation. It is concluded that short-wave radiation is the dominant factor in the ablation of the Biafo Glacier.View full abstractDownload PDF (4366K) -
Akeharu FUKUDA, Yoichi OGAWA, Masayoshi NAKAWO1983 Volume 45 Issue 4 Pages 169-176
Published: December 30, 1983
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSCrystal axes of minute subgrains in sea ice grown near Syowa Station, Antarctica were examined by X-ray Laue photographs. Subgrains which usually can not be distinguished by polarized light are bounded by subboundaries accompanied with brine pockets in a crystal grain of the polycrystals of sea ice. The misalignment angles of the crystal axes between adjacent subgrains were deduced from X-ray Laue photographs. Samples from 0.10 m and 0.17 m depths from the surface had the misalignment angles ranged from 0 to 10 degree or more. Those from 1.1 m and 1.5 m depths had the angles less than 7 degrees, and most of them were 0 degree. The average values of the misalignment angles were 7 and 3 degrees with the samples from 0.10 m and 0.17 m depths respectively, and 1 and 1.7 degrees with those from 1.1 m and 1.5 m depths respectively.
Subgrains are formed from cellular growth of ice into the constitutionally supercooled sea water. The misalignment between the adjacent subgrains could be caused by some disturbances associated with the growth of subgrains; intrinsically the thermal expansion force and extrinsically the effects of wave and underwater current.
The misalignment angle decreases with increase of the depth of sea ice partly because of the decrease of disturbances with increasing depth. Essential reason is to reduce the grain boundary energy in ice so that large misalignment angles disappear first, and misalignment angles are almost 0 degree near the bottom of sea ice although there occurs cellular growth.View full abstractDownload PDF (3077K) -
Hiroshi SUGIYAMA1983 Volume 45 Issue 4 Pages 177-187
Published: December 30, 1983
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSOn the Shinkansen train line to be operated in snowy regions, compacted snow is formed in the space, called the flangeway, beneath the wheel-glange. To examine the running stability on the flangeway compacted snow, fracture behavior of compacted snow was studied experimentally. Two types of experimental apparatus, which simulate the relation between the wheel-flange and the flangeway compacted snow, were manufactured : one was a falling weight type in which a penetrator having a shape and size similar to those of the wheel-flange collided against a specimen, and the other was a rotating disk type in which a specimen was pushed against a disk rotating at a peripheral speed of 2 to 60 m/s. The resistance of naturally deposited snow and artificially compacted snow against the penetrator was measured under the following parameters : impact speed, 4.8 to 17.5 m/s; density, 0.4 to 0.9 g/cm3; temperature of specimens, -2, -10 and -20°C; and four confinement conditions of specimens. The average of the snow resistance per unit length of the penetrator in each section of the penetrating distance was taken; here these values are called the snow resistance indices. The relation between the snow resistance indices F (kN/m) and the penetrating speed V (m/s) in the range of 4.8 to 15.8 m/s is given by the following formula : F=a+bV, where a (kN/m) and b (kNs/m2) are coefficients depending on the experimental parameters. F increases with increasing density of snow and also depends on the packing structure of compacted snow.View full abstractDownload PDF (4889K) -
Tsutomu TAKASHI, Takahiro OHRAI, Hideo YAMAMOTO, Jun OKAMOTO1983 Volume 45 Issue 4 Pages 189-196
Published: December 30, 1983
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSTo observe behaviors of ice lenses, extremely frost-susceptible and water-saturated clay sampled at Manaitabashi in Tokyo was used for frost-heaving experiment in an open system. Experimental conditions were : specimen size was 10 cm in diameter and 6 cm in height; no overburden pressure was applied; temperature at the top surface was kept at 4°C and the bottom -8°C; water was supplied from the top; and the freezing period was 6044 hours.
The frost-heave increased continuously and ice lenses grew during the experiment. The water supplied from the stop surface migrated through the unfrozen part and segregated on the high temperature side of the first ice lens which was nearest to the freezing front, meanwhile the fusion of ice occurred on the low temperature side of the ice lens. The first ice lens was transparent at first and became gradually white and opaque. The first ice lens disappeared after about 4000 hours. Water migrated through the frozen soil between the first and second ice lenses refroze on the high temperature side of the second ice lens. This phenomenon is defined as the “regelation”. It is revealed that ice lenses except the first one can grow in absorbing the water supplied by regelation under such condition that the ice lenses are unable to absorb water directly through unfrozen soil. Hydraulic conductivity of frozen Manaitabashi clay was estimated from the regelation rate, being 2×10-11 cm/s to 1.5×10-12 cm/s at the temperature range of -5°C to -2.2°C in the soil between the first and the second ice lens.View full abstractDownload PDF (3026K) -
Katutosi TUSIMA, Masayuki NAKAGAWA, Kunio KAWADA1983 Volume 45 Issue 4 Pages 197-200
Published: December 30, 1983
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSDownload PDF (7646K) -
Masami FUKUDA, Sadatoshi MIURA, Tadateru NISIMURA1983 Volume 45 Issue 4 Pages 201-204
Published: December 30, 1983
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSDownload PDF (3127K)
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