Hänninen, Pekka

Repo, Tapani

Sutinen, Raimo

Venäläinen, Ari

English

Jukuri

www.gtk.fiRoot-zone soil water content and temperature at snow covered and snow-free sites in southern boreal FinlandRaimo Sutinen 1, Pekka Hänninen 2, Tapani Repo 3, Ari Venäläinen 4 In cold climate of Fennoscandia soils experience ephemeral freezing and snow cover. Snowmelt impacts on run-off and solute transport, but also the presence of a snowpack governs the length of a growing season. Limited information, however, is available on the response of frozen soil to air temperature rise in spring in contrasting conditions, with and without snowpack. We studied time series of soil temperature and unfrozen soil water content during thawing of frozen soil in spring 2004 and 2006 at two sites differing in texture and hydraulic features in mid-boreal climate of Finland. We describe the changes in soil temperature and water content after constant rise of air temperature (Tair) above 0°C in spring (denoted as 0 in the x-axis of the graphs.GEOLOGICAL SURVEY OF FINLANDJaamankangas site, located on ice-marginal end-moraine and is composed of sandy stratified materials and covered by forest dominated by Norway spruce (Picea abies L. Karst.), was kept clean of snow through winter. The mid-boreal Multia site, located on a drumlin, i.e. elongated moraine ridge and composed of coarse-textured till and carries forest stand dominated by Norway spruce, got natural snow cover. Soil water content recorded with CS615 TDR-probes and soil temperature with T107-sensors and automatically controlled and stored with CR10X data-loggers (Campbell Scientific, Logan UT). The instrumentation was made at soil depths of 10, 30, 50, 70, and 90 cm and the timing of daily measurements was set as follows; 03, 06, 09, 12, 15, 18 and 21 UTC, respectively.We found that after constant rise of Tair above 0°C in spring, the soil was frozen for a month at all depths of the soil sequence at Jaamankangas site. Only T10 increased above 0°C after a month. After 20 days with constant rise of Tair above zero, the soil qv at 10-, 30- and 50-cm-depths showed an increase. At Multia site, the rise in Tair above 0°C resulted in unimpeded infiltration of meltwater released from snowpack into the frozen soil. Hence unfrozen soil water is available for roots concurrently with melting of snowpack. The lack of snow results in subzero soil temperature and lack of water for at least three weeks after the Tair has risen above 0°C. 1 Geological Survey of Finland, P.O. Box 77, Fin-96101 Rovaniemi2 Geological Survey of Finland, Betonimiehenkuja 4, FIN-02400 Espoo3 Finnish Forest Research Institute, P.O. Box 68, FIN-80101 Joensuu 4 Finnish Meteorological Institute P.O. Box 503, FIN-00101 HelsinkiE-mail raimo.sutinen@gtk.fi 

Root-zone soil water content and temperature at snow covered and snow-free sites in southern boreal Finland

https://jukuri.luke.fi/bitstream/10024/542611/2/2007_Sutinen%20et%20al%202007_Soil%20processes%20under%20extreme%20...%20Bayreuth_Root-zone%20soil%20water%20and%20soil%20frost.pdf

Root-zone soil water content and temperature at snow covered and snow-free sites in southern boreal Finland

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