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| Titel |
Sand box experiments to evaluate the influence of subsurface temperature probe design on temperature based water flux calculation |
| VerfasserIn |
M. Munz, S. E. Oswald, C Schmidt |
| 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 ; 15, no. 11 ; Nr. 15, no. 11 (2011-11-18), S.3495-3510 |
| Datensatznummer |
250013027
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| Publikation (Nr.) |
 copernicus.org/hess-15-3495-2011.pdf |
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| Zusammenfassung |
| Quantification of subsurface water fluxes based on the one dimensional
solution to the heat transport equation depends on the accuracy of measured
subsurface temperatures. The influence of temperature probe setup on the
accuracy of vertical water flux calculation was systematically evaluated in
this experimental study. Four temperature probe setups were installed into a
sand box experiment to measure temporal highly resolved vertical temperature
profiles under controlled water fluxes in the range of ±1.3 m d−1.
Pass band filtering provided amplitude differences and phase shifts of the diurnal
temperature signal varying with depth depending on water flux. Amplitude
ratios of setups directly installed into the saturated sediment significantly
varied with sand box hydraulic gradients. Amplitude ratios provided an
accurate basis for the analytical calculation of water flow velocities, which
matched measured flow velocities. Calculated flow velocities were sensitive
to thermal properties of saturated sediment and to temperature sensor spacing, but
insensitive to thermal dispersivity equal to solute dispersivity. Amplitude
ratios of temperature probe setups indirectly installed into piezometer pipes
were influenced by thermal exchange processes within the pipes and
significantly varied with water flux direction only. Temperature time lags of
small sensor distances of all setups were found to be insensitive to vertical
water flux. |
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