This study reports the results of field experiments carried out from June to October 1995 in the Levinson-Lessing Lake catchment on Taymyr Peninsula, Siberia (74o26.3'N, 98o46.4'E).
The objective is to study the solute distribution and movement for one continuous seasonal freeze-thaw cycle in the active layer under a variety of geomorphological settings within the lake watershed. Three slopes differing in parent material, aspect, inclination, vegetation and thaw depth of the active layer have been instrumented with suction lysimeters, wells, TDR and temperature probes in 1994. Weather was recorded on two automatic stations close to the measuring sites.
Time domain reflectometry (TDR) is used to determine in situ volumetric unfrozen moisture content of the frozen and unfrozen active layer. In addition, bulk electrical conductivities are calculated using the approach and computer program of Heimovaara and de Water (1993).
Soil water electrical conductivities for frozen and unfrozen soils are calculated using the approach of van Loon (1991) and compared to electrical conductivities of the soil suction lysimeters at the same sites. Suction cup measurements are 50-100% higher than TDR measurements of electrical conductivity. Solute concentrations determinded by suction cups and TDR measurements in the unfrozen active layer are relatively stable during the summer with concentrations increasing with soil depth. During thawing and freeze-back, electrical conductivity measurements calculated using TDR show a great deal of variability possibly suggesting the redistribution of solutes within the frozen active layer. In the frozen active layer before spring thaw solute concentrations have a maximum of up to 1800 mS/cm.
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Julia Boike Alfred Wegener Institute for Polar and Marine Research Telegrafenberg A43 14473 Potsdam, Germany Phone: +49-331-2882131 Fax: +49-331-2882137 e-mail: jboike@awi-potsdam.de Wilko K. P. van Loon Department of Agricultural Engineering and Physics AGROTECHNION University of Wageningen Bomenweg 4, 6703 HD Wageningen, The Netherlands e-mail: wilko.vanloon@user.aenf.wau.nl Pier P. Overduin (Paul) Overduin Department of Geography York University 4700 Keele St. North York, Ontario, M3J 1P3, CANADA pier@yorku.ca Hans W. Hubberten Alfred Wegener Institute for Polar and Marine Research 14473 Potsdam, Germany Phone: +49-331-2882131 e-mail: hubbert@awi-potsdam.de