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| Titel |
A qualitative description of shallow groundwater effect on surface temperature of bare soil |
| VerfasserIn |
F. Alkhaier, R. J. Schotting, Z. Su |
| 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 ; 13, no. 9 ; Nr. 13, no. 9 (2009-09-30), S.1749-1756 |
| Datensatznummer |
250012003
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| Publikation (Nr.) |
 copernicus.org/hess-13-1749-2009.pdf |
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| Zusammenfassung |
| Whether or not shallow groundwater affects skin temperature (the temperature
of soil surface) is important to detect depth and extent of shallow
groundwater by dint of remote sensing and important for land surface
modelling studies. Although few studies have been conducted to investigate
that effect, they have yielded contradicting conclusions and they stopped in
1982. To determine that shallow groundwater affects skin temperature, we
measured soil temperature at two different depths (5 and 10 cm) in seven
places with variable water table depths every ten minutes and for six days.
After that, we correlated the minimum, maximum and average daily
temperatures to average groundwater depth. We also built a simple numerical
model using a differential equations solver, Flex PDE, to simulate heat
transfer into soil profile and used it to simulate groundwater effect on
skin temperature. We found quite high negative correlation between the
maximum and average daily soil temperature and groundwater depth.
Contrarily, we could hardly find any correlation between the daily minimum
temperature and groundwater depth. Numerical simulations, though simple,
were useful in showing that groundwater shifted skin temperature curves up
in the winter and down in the summer without affecting the shape of the
curve. We conclude that shallow groundwater affects skin temperature
directly by its distinctive thermal properties in the soil profile and
indirectly by affecting soil moisture which in turn has many different and
contradictory effects on skin temperature. This study recommends building a
comprehensive numerical model that simulates the effect of shallow
groundwater on skin temperature and on the different energy fluxes at land
surface. |
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