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Volume 37 (1975)
- Issue 4 Pages 41-
- Issue 3 Pages 107-
- Issue 2 Pages 55-
- Issue 1 Pages 1-
Volume 37, Issue 4
Displaying 1-6 of 6 articles from this issue
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[in Japanese]1975 Volume 37 Issue 4 Pages 41
Published: December 25, 1975
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSDownload PDF (2872K) -
Shinji MAE, Hisao WUSHIKI, Yutaka AGETA, Keiji HIGUCHI1975 Volume 37 Issue 4 Pages 161-169
Published: December 25, 1975
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSA thermal drilling was carried cut in August of 1974 on the Khumbu Glacier flowing from Mt. Sagarmatha (English name Everest) in the East Nepal Himalayas. The drilling site was set at 5, 360 m above sea-level in the upper part of the ablation area of the glacier.
The drilling was continued to a depth of 20.3 m where the drilling stopped due to the freezing of the drilled hole. Down to the depth, the relationship between the depth and the time of drilling was obtained, and the analysis of the results obtained showed that there were 7 layers down to a depth of 20 m. Three layers of them were ordinary glacier ice layers, three layers were blue ice layers or ice layers contaminated with dirt, and one layer corresponded to a vertically distributed ice layer containing air bubbles or a horizontally distributed ice layer containing water.
A simple calculation of the freezing rate of the drilled hole showed that the ice temperature at a depth of 2 m was below -2°C at the time of drilling. The measurement of the resistance of a thermister put into the hole showed the ice temperature at a depth of 2.7 m was -5.3°C on 23rd November. Therefore, it was concluded that the distribution of ice temperature in the ablation area of the glacier might be of the polar type.View full abstractDownload PDF (7380K) -
Tetsuro NAKATAO1975 Volume 37 Issue 4 Pages 170-173
Published: December 25, 1975
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSThe author previously reported (Nakatao, 1964) on a snowcover densimeter for continuous measurement of density distribution of complex layered snow structure observed in the Hokuriku district. In the meter the copper plummet electrically heated melts the snowcover and sinks from the surface toward the ground. The instantaneous subsidence rate of the plummet gives the local density of the snowcover.
The present paper reports that the practical design of the meter was improved so that the field operation can be carried out rapidly and even in the rainy or snowy weather. The subsidence rate of the plummet is of the order of 0.1 m/min. The meter is usable under high air temperature, for example 10°C, whereas the snowsampler is not. Lastly a snowcover with thin layers (510 mm thick) of remarkablly high or low density is observed.View full abstractDownload PDF (878K) -
Tetsuro NAKATAO, Shigeru KITAGAWA1975 Volume 37 Issue 4 Pages 174-181
Published: December 25, 1975
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSIn Fukui Prefecture, the snowcover depth, H, varies remarkably with meteorological factors. In the present paper, the distribution of H is discussed in terms of the distance from the seashore, x, and the altitude, z, that is
H=H0+Bx+Dz
where H0, B and D are constants.
The following facts are noticeable : (1) The above expression explains well the observed distribution in the greater part of Fukui Prefecture. (2) When the deviation of the present expression from the observed depth is illustrated in a contour map, the following rapid-melting zones appear : (i) first one along the seashore, as previously reported, (ii) second along the Kuzuryu River, that suggests the effect of the sea-wind, and (iii) another zone around Fukui City where the population is dense.View full abstractDownload PDF (1438K) -
Kazuo GOTO, Daisuke KUROIWA1975 Volume 37 Issue 4 Pages 182-191
Published: December 25, 1975
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSIt was found that quite heavy and hard snow accretion on transmission lines occurred in the Hokkaido district of Japan, and a preventive measure was conceived with the newly devised apparatus which produced wet snow storm artificially.
It has been accepted by many authors that in the Hokuriku district, the accretion of wet snow on electric wires occurs at the air temperature between -1.51.5°C, that its density is less than 0.2g/cm3, and that if the wind velocity exceeds 8 m/sec, the snow is blown off. In Hokkaido, however, it was found that the accretion of wet snow on the transmission lines occurred even when the wind velocity exceeded 10 m/sec and that it grew up to 1020 cm in diameter and its density attained to 0.60.8 g/cm3.
In order to study the mechanism of snow accretion on electric wires in detail, a wind tunnel equipped with a device that artificially produced wet snow was contrived. According to the experiments with this apparatus, a lump of wet snow deposited on the surface of the stranded wire began to rotate sliding along the strands of the wire, and then developed into a large cylindrical ice deposit. Therefore, if the sliding rotation along the strands is stopped, its cylindrical growth may be arrested. When plastic rings of 24 mm in thickness were attached to the surface of the stranded wire at intervals of 1.52 times the length of the stranding pitch, the glide and the rotation of the accreted snow along the strands could be stopped by the rings.
These techniques were very effective for the short spans, less than 100 m, of the practical transmission lines with ACSR (aluminium conductor steel reinforced) of 13.518 mm in diameter, but the de-icing effect of plastic rings was reduced for the long spans of the transmission lines because of the twists of wires themselves. In the latter case, the anti-torsion weights of 0.8 kg-m were attached at intervals less than 100 m to prevent the wires from twisting.View full abstractDownload PDF (13069K) -
Kou KUSUNOKI1975 Volume 37 Issue 4 Pages 192-200
Published: December 25, 1975
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSAs a preliminary step to elucidate the role of pack-ice in atmosphere-ocean interactions in the Antarctic Ocean, shipboard sea-ice observation data collected by the Japanese Antarctic Research Expedition in 1957-1975 and relevant meteorological satellite data collected in 1966-1970 are analysed in mesoscale. Changes in the position of pack-ice edge on the meridian of 40° East show an average retreat speed of 4 km/day in December-January period and 1.9 km/day in February-March, still leaving fast-ice fringe about 45 km in width. Morphological features and drift characteristics of the pack ice are described in parallel with the fast-ice, giving the drift to 250° (west) with a speed of 5 cm/sec near the shore and about 30 cm/sec at the offings. Satellite data supplemented with the shipboard data are also analysed in terms of advance and retreat of pack-ice edge along the 40° East in longitude. Due to the paucity of the satellite data in the winter, detailed vicissitude of the pack-ice is not deciphered, but the extreme ice-edge in the mid-winter was about 5557°S. Maneuverability of expedition ships in the pack-ice near Syowa Station is mentioned.View full abstractDownload PDF (1558K)
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