Formation processes of ice body revealed by the internal structure of perennial snow patches in Japan
Formation processes of ice body revealed by the internal structure of perennial snow patches in Japan
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日本常年雪地内部结构揭示冰体形成过程
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
K. Kawashima
中科院分区：
文献类型：
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作者：
K. Kawashima
根据日本多年积雪内部结构的特点，阐明其从雪到冰的转化过程，在1995年和1996年的消融期间，对位于不同山区的8个多年积雪斑块进行了岩心钻探。包括地层、密度和液态水含量在内的岩心分析表明，冰体的存在是日本主要由飘雪滋养的常年雪片的共同特征。此外，水饱和的积雪层（积雪含水层）的上方形成的积雪-冰过渡在消融期间。在这种类型的雪斑，从积雪到冰的转变可能在一年内完成的水饱和的积雪，这是高度致密的积雪含水层的初冬冻结。在主要由雪崩滋养的常年积雪中，无法确定冰体的存在，因为雪中嵌入的碎片中断了钻探。然而，冰体的形成过程不太可能与由积雪滋养的雪块相同。雪崩形成的雪片存在于相对较低的海拔，在新的积雪堆积之前，空气温度并不低到足以冻结水饱和的积雪层。
To clarify the transformational processes from firn to ice of perennial snow patches in Japan on the basis of their characteristics of internal structure, core drillings were carried out during the ablation periods of 1995 and 1996 on eight perennial snow patches, located in different mountain areas. The core analyses including stratigraphy, density and liquid water content revealed that the existence of an ice body was a common feature of perennial snow patches nourished mainly by drifting snow in Japan. In addition, a water-saturated firn layer (firn aquifer) is formed just above the firn-ice transition during the ablation period. In this type of snow patch, the transformation from firn to ice may be completed in a single year by early-winter freezing of water-saturated firn which was highly densified in the firn aquifer. In perennial snow patches nourished mainly by snow avalanches, the existence of ice bodies could not be ascertained, because debris embedded in the snow interrupted the drilling. However, it is unlikely that an ice body can 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 enought to freeze the water-saturated firn layer.