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| Titel |
Shallow groundwater effect on land surface temperature and surface energy balance under bare soil conditions: modeling and description |
| VerfasserIn |
F. Alkhaier, G. N. Flerchinger, 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 ; 16, no. 7 ; Nr. 16, no. 7 (2012-07-03), S.1817-1831 |
| Datensatznummer |
250013351
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| Publikation (Nr.) |
 copernicus.org/hess-16-1817-2012.pdf |
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| Zusammenfassung |
| Understanding when and how groundwater affects surface temperature and
energy fluxes is significant for utilizing remote sensing in groundwater
studies and for integrating aquifers within land surface models. To
investigate the shallow groundwater effect under bare soil conditions, we
numerically exposed two soil profiles to identical metrological forcing. One
of the profiles had shallow groundwater. The different responses that the
two profiles manifested were inspected regarding soil moisture, temperature
and energy balance at the land surface. The findings showed that the two
profiles differed in three aspects: the absorbed and emitted amounts of
energy, the portioning out of the available energy and the heat fluency in
the soil. We concluded that due to their lower albedo, shallow groundwater
areas reflect less shortwave radiation and consequently get a higher
magnitude of net radiation. When potential evaporation demand is
sufficiently high, a large portion of the energy received by these areas is
consumed for evaporation. This increases the latent heat flux and reduces
the energy that could have heated the soil. Consequently, lower magnitudes
of both sensible and ground heat fluxes are caused to occur. The higher soil
thermal conductivity in shallow groundwater areas facilitates heat transfer
between the top soil and the subsurface, i.e. soil subsurface is more
thermally connected to the atmosphere. For the reliability of remote sensors
in detecting shallow groundwater effect, it was concluded that this effect
can be sufficiently clear to be detected if at least one of the following
conditions occurs: high potential evaporation and high contrast between day
and night temperatures. Under these conditions, most day and night hours are
suitable for shallow groundwater depth detection. |
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