| 翻訳と辞書 |
| Strudel (ice) ： ウィキペディア英語版 |
Strudel (ice)
A strudel (plural: strudel)〔https://en.wiktionary.org/wiki/Strudel.〕〔This plural form was recommended, and used, by E. Reimnitz and his colleagues.〕 is a vertical hole in sea ice through which downward jet-like, buoyancy-driven drainage of flood water is thought to occur.〔Reimnitz, E. and Bruder, K.F., 1972. River discharge into an ice-covered ocean and related sediment dispersal, Beaufort Sea, Coast of Alaska. Geological Society of America Bulletin, 83(3): 861-866.〕〔Walker, H.J., 1973. Salinity changes in the Colville River delta, Alaska, during breakup, International Symposia on the Role of Snow and Ice in Hydrology, Symposium on Properties and Processes, Banff, Canada, pp. 514-527.〕〔 This feature is less than a few tens of meters in size and typically occurs within 30 km from a river mouth, in the sea ice expanse that is fastened to the coastline (known as ''fast ice'').〔〔Reimnitz, E., Rodeick, C.A. and Wolf, S.C., 1974. Strudel scour: A unique marine geological phenomenon. Journal of Sedimentary Petrology, 44(2): 409-420.〕 Once the water that flooded the ice has completely drained off the ice surface, strudel become recognizable by a radial pattern of feeder channels that lead to the hole.〔〔〔Reimnitz, E., 2002. Interactions of river discharge with sea ice in proximity of Arctic Deltas: A Review. Polarforschung, 70: 123-134.〕 They are elongated and irregularly spaced, with the larger ones up to several kilometers apart.〔 Their distribution tends to be controlled by weak areas in the ice — in places, they line up along fractures or refrozen extensional cracks.〔 The ice sheet where they occur may be 2 m in thickness, at water depths (below the ice) in the order of a few meters.
The term ''strudel'' is German,〔 and designates a whirlpool, in reference to the water vortex that forms above these features during drainage. It has been suggested that this vortex could present a hazard for investigators wishing to study this phenomenon in the field, and that this would explain, at least partly, why little is known about strudel.〔, Section 7.3.〕
==Formation==
The formation of strudel is related to the break up of a frozen river during the melting season, where this river runs into a sea ice expanse.〔〔〔 At that time, fresh water flows onto the fast ice with a progression rate of about 2–3 m/s, extending up to a few tens of kilometers away from the river mouth. Water depths above the ice surface may be up to a few meters.〔〔〔 A strudel forms as a result of water carving its way through the ice sheet. Drainage is initiated through small openings or cracks in the ice resulting from the weight of the freshwater.〔 Some are reportedly enlarged seal-breathing holes.〔〔 Within a few days,〔Reimnitz, E., Kempema, E.W. 1982, Dynamic ice-wallow relief of northern Alaska’s nearshore. J. Sediment Petrol 52, 451-61.〕 the water drains off the ice. Drainage is driven by the buoyancy of the ice, not by the density difference between freshwater and sea water.〔〔 The pressure difference responsible for that flow is a function of the ice thickness and the difference in unit weight between the ice and the water.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Strudel (ice)」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|