Skip to main content

Microstructure-dependent densification of polar firn derived from X-ray microtomography

Buy Article:

$35.11 plus tax (Refund Policy)


The densification of dry polar snow and firn results in a continuous increase of density with depth accompanied by significant density fluctuations within seasonal layers. Density measurements of high spatial resolution reveal a persistent minimum of density fluctuations in the vicinity of the snow^firn transition (0.55–0.65 g cm−3) in firn-core records. In this study we give an explanation for the fluctuation minimum by applying a new method of X-ray microtomography to obtain three-dimensional (3-D) structural data of a Greenland firn core. At 13 different depths between 10 and 78 m a set of 16 samples of 40 cm total length for each depth interval was measured. A reconstructed firn segment of 40 cm covers 1–2 years of snow accumulation. Using digital image analysis techniques, different structural parameters are estimated including 3-D pore and particle sizes and specific surface areas. It is shown that the densification rates of snow and firn layers consisting of coarse particles are much higher than those consisting of fine particles within the same depth interval. This causes a density crossing of fine- and coarse-grained layers with a minimum of density variations at the crossover point. This crossing-over implies that formerly dense layers in the seasonal density signal are not of the same origin as dense layers in the deeper part of the firn column and that the seasonal density signal will totally change shape with depth. It is speculated that in coarse- and fine-grained firn the dominant mechanism of densification acts over different regimes of density.

Document Type: Research Article


Publication date: March 1, 2004

More about this publication?
  • The Journal of Glaciology is published six times per year. It accepts submissions from any discipline related to the study of snow and ice. All articles are peer reviewed. The Journal is included in the ISI Science Citation Index.
  • Editorial Board
  • Information for Authors
  • Ingenta Connect is not responsible for the content or availability of external websites

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more