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| Titel |
Comparison of algorithms and parameterisations for infiltration into organic-covered permafrost soils |
| VerfasserIn |
Y. Zhang, S. K. Carey, W. L. Quinton, J. R. Janowicz, J. W. Pomeroy, G. N. Flerchinger |
| 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. 5 ; Nr. 14, no. 5 (2010-05-11), S.729-750 |
| Datensatznummer |
250012298
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| Publikation (Nr.) |
 copernicus.org/hess-14-729-2010.pdf |
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| Zusammenfassung |
Infiltration into frozen and unfrozen soils is critical in hydrology,
controlling active layer soil water dynamics and influencing runoff. Few
Land Surface Models (LSMs) and Hydrological Models (HMs) have been
developed, adapted or tested for frozen conditions and permafrost soils.
Considering the vast geographical area influenced by freeze/thaw processes
and permafrost, and the rapid environmental change observed worldwide in
these regions, a need exists to improve models to better represent their
hydrology.
In this study, various infiltration algorithms and parameterisation methods,
which are commonly employed in current LSMs and HMs were tested against
detailed measurements at three sites in Canada's discontinuous permafrost
region with organic soil depths ranging from 0.02 to 3 m. Field data from
two consecutive years were used to calibrate and evaluate the infiltration
algorithms and parameterisations. Important conclusions include: (1) the
single most important factor that controls the infiltration at permafrost
sites is ground thaw depth, (2) differences among the simulated infiltration
by different algorithms and parameterisations were only found when the
ground was frozen or during the initial fast thawing stages, but not after
ground thaw reaches a critical depth of 15 to 30 cm, (3) despite
similarities in simulated total infiltration after ground thaw reaches the
critical depth, the choice of algorithm influenced the distribution of water
among the soil layers, and (4) the ice impedance factor for hydraulic
conductivity, which is commonly used in LSMs and HMs, may not be necessary
once the water potential driven frozen soil parameterisation is employed.
Results from this work provide guidelines that can be directly implemented
in LSMs and HMs to improve their application in organic covered permafrost
soils. |
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