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Transformational processes from firn to ice in perennial snow patches of Japan and in the wet-snow zone of temperate glacier
http://hdl.handle.net/10191/23699
http://hdl.handle.net/10191/236999f5c50b8-6550-4e7f-93f1-215824798b93
| 名前 / ファイル | ライセンス | アクション |
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本文 (11.2 MB)
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| Item type | 学位論文 / Thesis or Dissertation(1) | |||||
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| 公開日 | 2013-10-09 | |||||
| タイトル | ||||||
| タイトル | Transformational processes from firn to ice in perennial snow patches of Japan and in the wet-snow zone of temperate glacier | |||||
| タイトル | ||||||
| タイトル | Transformational processes from firn to ice in perennial snow patches of Japan and in the wet-snow zone of temperate glacier | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源 | http://purl.org/coar/resource_type/c_46ec | |||||
| タイプ | thesis | |||||
| その他のタイトル | ||||||
| その他のタイトル | 多年性雪渓及び温暖氷河におけるフィルンの氷化過程に関する研究 | |||||
| 著者 |
Kawashima, Katsuhisa
× Kawashima, Katsuhisa |
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| 著者別名 | ||||||
| 識別子Scheme | WEKO | |||||
| 識別子 | 48464 | |||||
| 姓名 | 河島, 克久 | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | This study aims at clarifying transformational processes from firn to ice ill perennial snow patches of Japan and in the wet-snow zone of temperate glaciers. For this purpose, many core drillings on perennial snow patches in Japan and compression, experiments of water-saturated firn under constant pressures were made, with special attention to the mechanism for controlling the formation of ice body. Prior to the field observations, a portable calorimeter was developed to facilitate the measurement of liquid water content of wet firn in mountain fields. It is composed of a metal-coated container made of' insulating materials and a lid of the container with a small thermistor thermometer. Its strong points are its light weight, small size and easy fabrication. The total weight of the device is as light as 0.25 kg, which is less than 10% of the snow-water content meter widely used in Japan. The results of experiments revealed that the device is capable of measuring liquid water content in 2 minutes with an accuracy of 2%. The new device was used for determining the dry density of wet firn in perennial snow patches. Depending on the major source of nourishment, perennial snow patches in Japan can be classified into two major types; snow patches developed mainly from drifting snow and those from avalanches. The internal structure of perennial snow patches nourished mainly by drifting snow was characterized by a 1-2 m-thick water-saturated firn layer (firn aquifer) overlying an ice body during the ablation period. Such a firn aquifer has been found in the wet-snow zone of many temperate glaciers. In this type of snow patch, the snow can be transformed into ice in a single year so that 0.3-2.3 m of ice is added to the ice body each year when the mass budget is positive. A small part of the annual ice layer, less than 0.3 m thick, can be explained by the superimposed ice formed early in malt season. Although the densification of the water-saturated firn layer proceeded rapidly, the transformation from firn to ice could not be recognized during the ablation period because of a rapid decrease in overburden pressure. The model calculation strongly suggested that the cold wave penetration early in winter can transform the water-saturated and/or wet firn into ice by freezing of liquid water in firn to form continuous masses of ice in perennial snow parches in Japan. In avalanche-fed perennial snow patches, the existence of an ice body could not be ascertained, because debris embedded in the firn interrupted the drilling. However, it is unlikely that an ice body call be formed by the same processes as in snow patches nourished by drifting snow. Avalanche-fed snow patches exist at relatively low altitudes and air temperatures prior to new snow accumulation are not low enough to freeze the water-saturated and/or wet firn layer. If this type of snow patch has an ice body, the densification of water-saturated firn due to overburden pressure must dominate the ice formation like the wet-snow zone of temperate glaciers. Compression experiments of water-saturated firn revealed that the necessary time for ice formation in the firn aquifer decreases exponentially as the overburden pressure increases, showing that the transformation from firn to ice can be completed within the period when the firn aquifer exists if the overburden pressure is above 0.12-0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth-density curves in the wet-snow zone of temperate glaciers. It was concluded that the depth of firm-ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m. | |||||
| 内容記述 | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | 学位の種類: 博士（理学）. 報告番号: 乙第1627号. 学位記番号: 新大博（理）乙第29号. 学位授与年月日: 平成10年3月12日 | |||||
| 書誌情報 | p. 1-93, 発行日 1998-03-12 | |||||
| 出版者 | ||||||
| 出版者 | 新潟大学 | |||||
| 著者版フラグ | ||||||
| 値 | ETD | |||||
| 学位名 | ||||||
| 学位名 | 博士（理学） | |||||
| 学位授与機関 | ||||||
| 学位授与機関名 | 新潟大学 | |||||
| 学位授与年月日 | ||||||
| 学位授与年月日 | 1998-03-12 | |||||
| 学位授与番号 | ||||||
| 学位授与番号 | 13101B1627 | |||||
| 学位記番号 | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | 新大博（理）乙第29号 | |||||
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Cite as
Kawashima, Katsuhisa, 1998, Transformational processes from firn to ice in perennial snow patches of Japan and in the wet-snow zone of temperate glacier: 新潟大学, p. 1–93.
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