Antarctic Science

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Antarctic Science (2010), 22:419-434 Cambridge University Press
Copyright © Antarctic Science Ltd 2010
doi:10.1017/S0954102010000234

Earth Sciences

A dynamic physical model for soil temperature and water in Taylor Valley, Antarctica


H.W. Hunta1 c1, A.G. Fountaina2, P.T. Dorana3 and H. Basagica2

a1 Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, USA
a2 Department of Geology, Portland State University, Portland, OR 97201, USA
a3 Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
Article author query
hunt hw [PubMed]  [Google Scholar]
fountain ag [PubMed]  [Google Scholar]
doran pt [PubMed]  [Google Scholar]
basagic h [PubMed]  [Google Scholar]

Abstract

We developed a simulation model for terrestrial sites including sensible heat exchange between the atmosphere and ground surface, inter- and intra-layer heat conduction by rock and soil, and shortwave and longwave radiation. Water fluxes included snowmelt, freezing/thawing of soil water, soil capillary flow, and vapour flows among atmosphere, soil, and snow. The model accounted for 96–99% of variation in soil temperature data. No long-term temporal trends in soil temperature were apparent. Soil water vapour concentration in thawed surface soil in summer often was higher than in frozen deeper soils, leading to downward vapour fluxes. Katabatic winds caused a reversal of the usual winter pattern of upward vapour fluxes. The model exhibited a steady state depth distribution of soil water due to vapour flows and in the absence of capillary flows below the top 0.5 cm soil layer. Beginning with a completely saturated soil profile, soil water was lost rapidly, and within a few hundred years approached a steady state characterized by dry soil (< 0.5% gravimetric) down to one metre depth and saturated soil below that. In contrast, it took 42 000 years to approach steady state beginning from a completely dry initial condition.

(Received August 11 2009)

(Accepted January 27 2010)

(Online publication May 13 2010)

Key wordscapillary water; longwave radiation; matric potential; permafrost; solar radiation; water vapour

Correspondence:

c1 billh@nrel.colostate.edu


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