文章基本信息

标题：A Firn Densification Process in the High Accumulation Dome of Southeastern Greenland
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作者：Yoshinori Iizuka ; Atsushi Miyamoto ; Akira Hori 等
期刊名称：Arctic, Antarctic, and Alpine Research
印刷版ISSN：1523-0430
电子版ISSN：1938-4246
出版年度：2017
卷号：49
期号：1
页码：13-27
DOI：10.1657/AAAR0016-034
摘要：We examine a firn core from a dome in southeast Greenland that exhibits distinct firn densification. The ice was −20.9 °C at 20 m depth, and the core gives an average accumulation rate of 1.0 m w.e. yr −1 in water equivalent. However, the close-off density of 830 kg m −3 occurs at 83.4–86.8 m depth, which is about 20-m shallower than that obtained from two empirical models. Where the density ρ > 750 kg m −3 , the densification appears faster than that from the empirical models. As a result, compared to the empirical coefficient, the actual compactive viscosity coefficient is nonlinear and decreases at ρ > 750 kg m −3 , indicating that the firn with a higher density is softer than that from the empirical result. We argue here that the high accumulation rate creates a high overburden pressure in a short time. Thus, the relative softness of the firn may arise from (1) there being not enough time to form bonds between grains as strong as those in a lower accumulation-rate area, and similarly, (2) the dislocation density in the firn being relatively high.