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| Titel |
Energy exchange of an alpine grassland on the northeastern Qinghai-Tibetan Plateau |
| VerfasserIn |
Lunyu Shang, Yu Zhang, Shihua Lv, Shaoying Wang |
| 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 |
250089003
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| Publikation (Nr.) |
 EGU/EGU2014-3184.pdf |
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| Zusammenfassung |
| The seasonal variability in the surface energy exchange of an alpine grassland on
the northeastern Qinghai-Tibetan Plateau was investigated using eddy covariance
measurements. Based on the change of air temperature and the seasonal distribution of
precipitation, a winter season and wet season were identified, which were separated by
transitional periods. For each period, the surface energy exchange exhibited distinct
patterns.
Daily mean net radiation (Rn) was almost always positive throughout the year. Sensible
heat flux (H) was almost always greater than latent heat flux (LE) during the winter season,
and LE was always greater than H during the wet season. Ground heat flux (G0) was
relatively low throughout the year. The annual mean net radiation was about 39% of the
annual mean solar radiation (Rs). Rn was relatively low during the winter season (21% of
Rs) compared to the wet season (55% of Rs), which can be explained by the difference in
surface albedo and moisture condition between the two seasons. H and LE had
different roles during different periods of the year. Annually, the main consumer
of net radiation was LE. During the winter season, H was dominant because of
the frozen soil condition and lack of precipitation. During the wet season LE was
dominant due to increased temperature and sufficient rainfall coupling with vegetation
development. LE was strongly controlled by Rn from June to August though surface
conductance (gc) and soil water content (θv) were high. During the transitional periods,
H and LE were nearly equally partitioned in the energy balance. The results also
suggested that the freeze-thaw condition of soil and the seasonal distribution of
precipitation had important impacts on the energy exchange in this alpine grassland. |
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