Frost boils and soil ice content: field observations


Contact
Paul.Overduin [ at ] awi.de

Abstract

Our aim is to measure and explain the seasonal changes in soil ice content in the frost boils of Galbraith Lake, Alaska. Instruments were installed in a frost boil to monitor the ground surface position and soil state over a period of 4 years. By comparing the subsidence and thaw rates, we calculate the soil ice content as a function of depth. Measured soil temperatures, liquid water contents and bulk apparent thermal conductivities are used to estimate latent heat production and release in the soil. The frost boil heaves during freezing and settles during thaw while the surrounding tundra heaves negligibly, but subsides measurably. Despite large changes in freezing rates from year to year, total heave and its distribution across the frost boil are similar between years. Winter air temperature and snow depth influence the freezing rate and ice distribution as a function of depth, but not the overall heave. This suggests that heave is controlled by water availability rather than the rate of heat removal from the soil. Areal ground subsidence rates between 2 and 5 cm/yr are due to the disappearance of ice at the base of the active layer, raising the possibility of ongoing thermokarst expansion around Galbraith Lake.



Item Type
Article
Authors
Divisions
Programs
Peer revision
ISI/Scopus peer-reviewed
Publication Status
Published
Eprint ID
16331
DOI 10.1002/ppp.567

Cite as
Overduin, P. P. and Kane, D. L. (2006): Frost boils and soil ice content: field observations , Permafrost and Periglacial Processes, 17 (4), pp. 291-307 . doi: 10.1002/ppp.567


Download
[img] PDF (Fulltext)
Ove2006b.pdf

Download (1MB)
Cite this document as:

Share


Citation

Research Platforms
N/A

Campaigns


Actions
Edit Item Edit Item