The low-frequency conductivity of snow near the melting temperature
Abstract:Dielectric measurements of snow were carried out in the temperature range −15° to 0°C and in the frequency range 50 Hz to 5 MHz. The snow samples (about 400 kg m−3 density) used were stored snow (average particle size: 2 mm) and hoar-frost (particle size: <1 to 5 mm). The frequency characteristics of dielectric parameters showed a dielectric dispersion (Davidson–Cole type) around 30 kHz and a low-frequency dielectric dispersion (Cole–Cole circular law type). The a.c. conductivity showed a dielectric dispersion around 30kHz and two characteristic constant values in the frequency ranges above 1 MHz and below 100 Hz (the high-frequency conductivity ∞ and the low-frequency conductivity LOW). The low-frequency conductivity LOW showed a peak at about −2°C. This behavior has never been noted by previous researchers. The LOW showed an activation energy of about 1eV below −5°C. This means that the LOW is mainly caused by a surface conduction. The activation energy increased with increasing temperature above −5°C. This means that the LOW in this temperature range is affected by the quasi-liquid layer on ice surfaces. The LOW above −2°C decreased with increasing temperature. The apparently curious behavior near the melting temperature is attributed to the numerous free ice surfaces within the porous snow. This conclusion was reached because our measurements without the free ice surfaces showed no such conductivity peaks for solid polycrystalline ice samples and for snow samples soaked with kerosene in the cooling process.
Document Type: Research Article
Publication date: 2001-01-01
- The Annals of Glaciology is a peer-reviewed, thematic journal published 2 to 4 times a year by the International Glaciological Society (IGS). Publication frequency is determined and volume/issue numbers assigned by the IGS Council on a year-to-year basis and with a lead time of 3 to 4 years. The Annals of Glaciology is included in the ISI Science Citation Index from volume 50, number 50 onwards.
Themes can be on any aspect of the study of snow and ice. Individual members can make a suggestion for a theme for an Annals issue to the Secretary General, who will forward it to the IGS Publications Committee. The IGS Publication Committee will make a recommendation for an individual themed Annals issue, together with a potential Annals Chief Editor for that issue, to IGS Council. The IGS Council will make the decision whether to proceed, taking into account the spread of topics and the overall capacity for publication of pages in Annals.
- Editorial Board
- Information for Authors
- Ingenta Connect is not responsible for the content or availability of external websites