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| Titel |
Laboratory evidence for enhanced infiltration of ion load during snowmelt |
| VerfasserIn |
G. Lilbæk, J. W. Pomeroy |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 14, no. 7 ; Nr. 14, no. 7 (2010-07-29), S.1365-1374 |
| Datensatznummer |
250012376
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| Publikation (Nr.) |
 copernicus.org/hess-14-1365-2010.pdf |
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| Zusammenfassung |
| Meltwater ion concentration and infiltration rate into frozen soil both
decline rapidly as snowmelt progresses. Their temporal association is highly
non-linear and a covariance term must be added in order to use time-averaged
values of snowmelt ion concentration and infiltration rate to calculate
chemical infiltration. The covariance is labelled enhanced ion infiltration and represents the
additional ion load that infiltrates due to the timing of high meltwater
concentration and infiltration rate. Previous assessment of the impact of
enhanced ion infiltration has been theoretical; thus, experiments were
carried out to examine whether enhanced infiltration can be recognized in
controlled laboratory settings and to what extent its magnitude varies with
soil moisture. Three experiments were carried out: dry soil conditions,
unsaturated soil conditions, and saturated soil conditions. Chloride
solutions were added to the surface of frozen soil columns; the
concentration decreased exponentially over time to simulate snow meltwater.
Infiltration excess water was collected and its chloride concentration and
volume determined. Ion load infiltrating the frozen soil was specified by
mass conservation. Results showed that infiltrating ion load increased with
decreasing soil moisture as expected; however, the impact of enhanced ion
infiltration increased considerably with increasing soil moisture. Enhanced
infiltration caused 2.5 times more ion load to infiltrate during saturated
conditions than that estimated using time-averaged ion concentrations and
infiltration rates alone. For unsaturated conditions, enhanced ion
infiltration was reduced to 1.45 and for dry soils to 1.3. Reduction in
infiltration excess ion load due to enhanced infiltration increased slightly
(2–5%) over time, being greatest for the dry soil (45%) and least for
the saturated soil (6%). The importance of timing between high ion
concentrations and high infiltration rates was best illustrated in the
unsaturated experiment, which showed large inter-column variation in
enhanced ion infiltration due to variation in this temporal covariance. |
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