Journal of the Japanese Society of Snow and Ice

An estimate of the steady flow field along a flow line of Shirase Glacier, Antarctica

Shuhei TAKAHASHI, Masayoshi NAKAWO

1982 Volume 44 Issue 4 Pages 189-195
Published: December 30, 1982
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.5331/seppyo.44.189

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Along a flow line located approximately in the centre of the Shirase drainage basin, various components in conjunction with its flow have been estimated. Major input data for the estimates are the topography of the top and bottom surface of the ice sheet, the width between two adjacent flow lines, and the surface net balance. They are assumed to be independent on time, and determined based on previous observations. Additional assumptions, that the flow is in a steady state and laminar with no basal sliding, allow the estimations of the surface velocities and the strain rates along the flow line. It is shown further that horizontal as well as vertical components of the flow velocity could be calculated by the use of the continuity equation for a given location in the ice sheet. Both the internal flow line and the isochronal line are obtained from the flow vector.

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Freezing process in sea water around Syowa Station, Antarctica, in 1980

Shun'ichi KOBAYASHI, Nobuyoshi ISHIKAWA, Yasuhiko NAITO, Sadao KAWAGUC ...

1982 Volume 44 Issue 4 Pages 197-203
Published: December 30, 1982
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.5331/seppyo.44.197

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Sea ice around Syowa Station (69°00'S, 39°35'E) on East Ongul Island was broken and disappeared, which was caused by a heavy blizzard on March 18, 1980. This report describes in situ observations of freezing process of the sea after that incidence. The frazil ice formed frequently under cold air and windy conditions. The occurrence of frazil ice and the formation of sea ice together with the data of sea water temperature, air temperature, wind speed and cloudiness are reported. On March 19, the surface water temperature was +0.5°C and it decreased. Ice crystals suspended in water were observed on March 22 when the water temperature was -1.7°C which was near the freezing point. The sea around Syowa Station froze in April and the ice thickness increased until October.

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An empirical representation of snow-control cost as a function of snow-disaster index, population and regional snow conditions

Tetsuro NAKATAO, Mitsuharu MIZUKOSHI

1982 Volume 44 Issue 4 Pages 205-210
Published: December 30, 1982
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.5331/seppyo.44.205

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The severity of snow disaster in Japan depends on the conditions of natural environment and human activities. This paper at first describes the past research of present authors : Nakatao (1968, 1976) proposed a snow-disaster index T based on the climatic and snow removal conditions; Nakatao and Mizukoshi (1978) gave an empirical expression for prefectural snow-control cost M=γNT, where N is the population which reflects (an index of) social and economic conditions. The constant γ for each prefecture had a mean error of ±47%; further, Nakatao and Mizukoshi (1979) introduced the distance x from the sea-coast to the weather station in the most populous city (usually the capital of the prefecture) into an improved empirical expression where the mean error of γ was 33%. The rest of the paper describes an analysis of the relation between the population distribution in each prefecture and the snow-control cost; a new empirical formula for M is introduced for sparsely populated prefectures. Combining two formulas for densely-populated and sparsely-populated prefectures, the snow-control cost M is given, and the constant γ is within an error of 22% except for Yamaguchi Prefecture.

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Introduction of disaster index for the labor of manual snow-removal in Hokuriku, Japan

Tetsuro NAKATAO

1982 Volume 44 Issue 4 Pages 211-216
Published: December 30, 1982
Released on J-STAGE: January 22, 2010

DOIhttps://doi.org/10.5331/seppyo.44.211

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This paper reviews several indices for describing the intensity of snow disaster, proposed by the present author (Nakatao, 1968 and 1976) : the three fundamental indices P_θ for this air temperature, P_W for the precipitation and P_H for the maximum snow cover depth; and applied indices in consideration of the snow-removal operation. Secondly, this paper introduces a new disaster index U, which corresponds to the personal labor in energy E, when a civilian removes manually the snow cover from the road. Personal labor E in the Hokuriku district is expressed in terms of new snowfall depth h. snow cover depth H, road width and so on. In the expression obtained, introducing an equivalent depth of snow removal by λ H, where λ depends on the road condition and snow condition, its value is about 1.7. Rewriting h and H in the expression for E in terms of P_W, and P_H the manual snow-removal labor index U= kλP_WP_HB is obtained where k is a certain constant and B is the area of road of personal removal. The index gives the local difference of daily or annual labor in different distracts along the Japan sea.

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[title in Japanese]

[in Japanese]

1982 Volume 44 Issue 4 Pages 217-221
Published: December 30, 1982
Released on J-STAGE: January 22, 2010

DOIhttps://doi.org/10.5331/seppyo.44.217

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