Hydrological significance of soil frost for pre-alpine areas

Stähli, Manfred

doi:10.1016/j.jhydrol.2016.12.032

Cited by 14 publications

(15 citation statements)

References 45 publications

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“…6. The mod-CFGI frost depth also has some elevation dependence, but (WY 2006-2007), validation period (WY 2008, and overall (WY 2006(WY -2010 the spatial variation mainly follows land cover classification, which is similar to observations of frozen ground in the Swiss pre-Alpine zone (Stähli, 2017). This variation is partly due to the use of T rad and the increased heterogeneity in the snow depth.…”

Section: Snow Depth and Swe (Ti Vs Rti)supporting

confidence: 67%

“…Several plot-scale studies have shown that frozen ground can impede infiltration and thus enhance runoff (Bayard et al, 2005;Dunne and Black, 1971;Stähli et al, 1999). Several of these studies have also shown that frozen ground is highly variable temporally and spatially (Campbell et al, 2010;Shanley and Chalmers, 1999;Stähli, 2017), which affects the amount and type of runoff (Wilcox et al, 1997). The presence, spatial pattern, and depth of frozen ground are driven by mass (water) and energy balances.…”

Section: Introductionmentioning

confidence: 99%

“…The presence, spatial pattern, and depth of frozen ground are driven by mass (water) and energy balances. The energy available from the atmosphere to thaw the soil is subject to the insulation of the snowpack (Pearson, 1920;Willis et al, 1961) and ground cover, including any vegetation, woody debris, and leaf litter (Brown, 1966;Diebold, 1938;Fahey and Lang, 1975;Sartz, 1973;Stähli, 2017). MacKinney (1929) found that ground cover reduced the depth of frost penetration by 40 % at a test site in Connecticut.…”

Section: Introductionmentioning

confidence: 99%

“…Spatial variations of frozen ground within degree-day methods are typically based on variations in temperature (which are estimated from an elevation-temperature relationship) and variations in snowpack insulation (which are also typically inferred from an elevation-temperature relationship). Such reliance on elevation may lead to errors because Stähli (2017) found no clear connection between elevation and presence of frozen ground at test sites in the Swiss pre-Alpine zone.…”

Section: Introductionmentioning

confidence: 99%

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A simple temperature-based method to estimate heterogeneous frozen ground within a distributed watershed model

Follum

Niemann

Parno

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. Frozen ground can be important to flood production and is often heterogeneous within a watershed due to spatial variations in the available energy, insulation by snowpack and ground cover, and the thermal and moisture properties of the soil. The widely used continuous frozen ground index (CFGI) model is a degree-day approach and identifies frozen ground using a simple frost index, which varies mainly with elevation through an elevation-temperature relationship. Similarly, snow depth and its insulating effect are also estimated based on elevation. The objective of this paper is to develop a model for frozen ground that (1) captures the spatial variations of frozen ground within a watershed, (2) allows the frozen ground model to be incorporated into a variety of watershed models, and (3) allows application in data sparse environments. To do this, we modify the existing CFGI method within the gridded surface subsurface hydrologic analysis watershed model. Among the modifications, the snowpack and frost indices are simulated by replacing air temperature (a surrogate for the available energy) with a radiation-derived temperature that aims to better represent spatial variations in available energy. Ground cover is also included as an additional insulator of the soil. Furthermore, the modified Berggren equation, which accounts for soil thermal conductivity and soil moisture, is used to convert the frost index into frost depth. The modified CFGI model is tested by application at six test sites within the Sleepers River experimental watershed in Vermont. Compared to the CFGI model, the modified CFGI model more accurately captures the variations in frozen ground between the sites, inter-annual variations in frozen ground depths at a given site, and the occurrence of frozen ground.

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Section: Snow Depth and Swe (Ti Vs Rti)supporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A simple temperature-based method to estimate heterogeneous frozen ground within a distributed watershed model

Follum

Niemann

Parno

et al. 2018

Hydrol. Earth Syst. Sci.

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“…It is also important to discuss the effect of macropores on the infiltration into frozen soils, as found in our plot experiments, in the context of catchment‐scale reaction. The numerous connected and persistent air‐filled macropores created by flora and soil fauna combined with low frost depth (Watanabe and Kugisaki, 2016) seem to explain why many studies did not find an effect of frozen soils on catchment runoff responses in forests (Fuss et al, 2016; Lindström et al, 2002; Nyberg et al, 2001; Stähli, 2017). Therefore, surface runoff due to frozen soils seems to be more common in catchments with a deep frozen layer (>30 cm) or high water content in autumn and a low connected macroporosity by, for example, biopores.…”

Section: Discussionmentioning

confidence: 99%

Influences of Macropores on Infiltration into Seasonally Frozen Soil

Demand

Selker

Weiler

2019

Vadose Zone Journal

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Core Ideas Macropores allow water infiltration into a frozen soil close to 0°C and at high water saturation. Connected biopores channel water beneath the frozen layer. Frozen layer thickness in relation to connected macroporosity is a crucial factor. Infrared thermography can be used to measure frozen layer extent and variability. Water frozen in soil can reduce the soil infiltrability, depending on the water content. We hypothesize that air‐filled macropores control the infiltration of a seasonally frozen soil under high saturation degrees. Sprinkling experiments with different intensities on a seasonally frozen soil were conducted in two winters at high initial water contents. Brilliant Blue FCF (BB) was sprinkled on four plots equipped with soil moisture and temperature probes to mark flow paths. Frozen layer thickness was measured with infrared thermography of soil sections and overlaid with BB images. The frost depth of the experiments was 8 to 15 cm. Infiltration rates showed reduced infiltration compared with unfrozen conditions. By impeding refreezing of the infiltrating water with added NaCl, infiltration rates of 23 to 29 mm h−1 were measured. Without the addition of salt, the infiltration rates decreased to 5 to 10 mm h−1, attributed to pore blockage by refreezing water. Temperature measurements revealed that the frozen layer only thawed close to the soil surface during the experiments. Blue‐stained areas indicated that water was channeled through the frozen layer into the unfrozen soil. In addition, the soil moisture probes below the frozen layer measured an increase in unfrozen water content, whereas total water content in the frozen layer was constant. These observations were explained by a connected air‐filled porosity, such as biopores, which allowed water flow even under high initial water contents. These results illustrate the importance of macroporosity in relation to frost depth in controlling the infiltrability of seasonally frozen soils.

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