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| Titel |
Some practical notes on the land surface modeling in the Tibetan Plateau |
| VerfasserIn |
K. Yang, Y.-Y. Chen, J. Qin |
| 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. 5 ; Nr. 13, no. 5 (2009-05-27), S.687-701 |
| Datensatznummer |
250011867
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| Publikation (Nr.) |
 copernicus.org/hess-13-687-2009.pdf |
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| Zusammenfassung |
The Tibetan Plateau is a key region of land-atmosphere interactions, as it
provides an elevated heat source to the middle-troposphere. The Plateau
surfaces are typically characterized by alpine meadows and grasslands in the
central and eastern part while by alpine deserts in the western part. This
study evaluates performance of three state-of-the-art land surface models
(LSMs) for the Plateau typical land surfaces. The LSMs of interest are SiB2
(the Simple Biosphere), CoLM (Common Land Model), and Noah. They are run at
typical alpine meadow sites in the central Plateau and typical alpine desert
sites in the western Plateau.
The identified key processes and modeling issues are as follows. First, soil
stratification is a typical phenomenon beneath the alpine meadows, with
dense roots and soil organic matters within the topsoil, and it controls the
profile of soil moisture in the central and eastern Plateau; all models,
when using default parameters, significantly under-estimate the soil
moisture within the topsoil. Second, a soil surface resistance controls the
surface evaporation from the alpine deserts but it has not been reasonably
modeled in LSMs; an advanced scheme for soil water flow is implemented in a
LSM, based on which the soil resistance is determined from soil water
content and meteorological conditions. Third, an excess resistance controls
sensible heat fluxes from dry bare-soil or sparsely vegetated surfaces, and
all LSMs significantly under-predict the ground-air temperature gradient,
which would result in higher net radiation, lower soil heat fluxes and thus
higher sensible heat fluxes in the models. A parameterization scheme for
this resistance has been shown to be effective to remove these
biases. |
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