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| Titel |
A simple method for accurate reconstruction of istantaneous soil temperature profiles |
| VerfasserIn |
Marco Falocchi, Stefano Barontini, Roberto Ranzi |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098992
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| Publikation (Nr.) |
 EGU/EGU2014-14726.pdf |
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| Zusammenfassung |
| When assessing the energy and water balance of the hydrologically active soil layer, an
important role is played by the stored heat and by the heat flux at the bottom boundary of the
soil. Both these components are directly related to the istantaneous temperature profiles
which are usually described by integrating the Fourier equation. As a boundary
condition, the soil surface temperature or the temperature at a certain depth nearby the
soil surface can be used. The soil temperature signals show a typical asymmetrical
periodic–like pattern with a minimum in the morning and a maximum in the afternoon.
These characteristics suggest to solve the Fourier equation in terms of periodic
functions, which are often only roughly approximated by a single trigonometric
function.
In this framework we developed a simple method, based on the assessment of the
contribution of each harmonic to the solution, to estimate the Fourier coefficients of the
meaningful ones, knowing at least two temperature series at different depths.
Data of soil temperature at the depth of 5, 10, 15cm and soil heat flux at 7.5cm,
collected in Summer 2012 and Summer 2013 during the CividatEX experiment (Oglio
river basin, Central Italian Alps, 274ma.s.l.), were used to calibrate and test the
method.
The method allowed to estimate the apparent soil thermal diffusivity and to accurately
reproduce the temperature observations by means of the first three harmonics. The heat fluxes
and the soil heat storage were reconstructed both on the basis of calibration of thermal
conductivity and apparent soil thermal capacity, and on the basis of literature values. A
sensitivity analysis of the thermal soil properties to the soil water content is provided and
compared with the literature. |
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