The impact of accumulation rate on anisotropy and air permeability of polar firn at a high-accumulation site

被引：24

作者：

Hoerhold, Maria W. ^{[1
]}

Albert, Mary R. ^{[2
]}

Freitag, Johannes ^{[1
]}

机构：

[1] Alfred Wegener Inst Polar & Marine Res, D-27570 Bremerhaven, Germany

[2] USA, Cold Reg Res & Engn Lab, Hanover, NH 03755 USA

来源：

JOURNAL OF GLACIOLOGY | 2009年 / 55卷 / 192期

基金：

美国国家科学基金会;

关键词：

NEAR-SURFACE FIRN; SNOW; METAMORPHISM; ANTARCTICA; TRANSPORT;

D O I：

10.3189/002214309789471021

中图分类号：

P9 [自然地理学];

学科分类号：

0705 ; 070501 ;

摘要：

The first three-dimensional properties of polar firn obtained by X-ray microtomography are used to study the microstructure of snow on a 15 m deep firn core from West Antarctica. The snow is found to undergo coarsening down to approximately 2.5 m depth before grain growth and densification become the prevalent mechanisms of microstructure change. In contrast to previous assumptions, distinct anisotropy of the ice and pore geometry is observed throughout the profile, with a maximum at 2.5 m depth. The air permeability and the degree of anisotropy vary with depth and can be linked to short-term changes in accumulation rate via the residence time for which a certain snow layer stays in the uppermost 2.5 m. Patterns of the degree of anisotropy and air permeability of buried polar firn are relative indicators of past accumulation rates.

引用

页码：625 / 630

页数：6

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