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Titel |
Evapotranspiration of Kobresia pygmaea pastures under different stages of degradation |
VerfasserIn |
Wolfgang Babel, Heinz Coners, Tobias Biermann, Eva Falge, Yaoming Ma |
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 |
250093181
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Publikation (Nr.) |
EGU/EGU2014-7676.pdf |
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Zusammenfassung |
As part of the hydrological cycle, evapotranspiration plays an important role on the Tibetan
Plateau. Especially during the monsoon season feedbacks of evapotranspiration
on precipitation patterns are expected. The land cover on the Tibetan Plateau is
characterised by dense Kobresia pygmaea pastures and the alpine steppe with sparse
vegetation and large fractions of bare soil, as well as transition stages between
these extremes. These Kobresia pastures are likely subject to degradation due to
effects of climate change, livestock management, pica damage and other possible
influences.
We investigate the impact of potential degradation on summer evapotranspiration
magnitude and dynamics. Therefore eddy-covariance and lysimeter measurements
are conducted at Kema site, covered by Kobresia pastures with different stages of
degradation. Both methods show reasonable agreement. Two SVAT-type models
were adapted to the site-specific conditions and then serve to estimate potential
changes in land cover by changing the critical parameter. The model simulations
fit well to the eddy-covariance measurements. Finally the results were compared
with simulations adapted to Nam Co site as a representative of an alpine steppe
site.
We show that a fictive transition from Kobresia pastures to roughly bare soil
conditions slightly decreases daily evapotranspiration, but strongly increases its
variability. Such potential changes will exhibit a complex feedback on precipitation
patterns. |
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