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| Titel |
Biophysical Regulation of Carbon Fluxes over an Alpine Meadow Ecosystem in the Eastern Tibetan Plateau |
| VerfasserIn |
Shaoying Wang, Yu Zhang, Shihua Lü, Lunyu Shang |
| 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 |
250091019
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| Publikation (Nr.) |
 EGU/EGU2014-5284.pdf |
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| Zusammenfassung |
| We used the eddy covariance method to measure the CO2 exchange between the atmosphere
and an alpine meadow ecosystem in the eastern Tibetan Plateau, China in 2010. The
photosynthesis was depressed under low air temperature (Ta), high vapor pressure deficit
(VPD) and medium soil water content (SWC) conditions. Temperature was the most
dominant factor controlling ecosystem photosynthesis in this alpine meadow. Regardless of
photosynthetically active radiation (PAR), the relationship between net ecosystem
CO2 exchange (NEE) and Ta (VPD) showed positive correlation when Ta (VPD)
lower than optimal value 16.5 ° (0.55 kPa), whereas negative correlation when Ta
(VPD) higher than this value. The responses of NEE and ecosystem respiration
(Reco) to SWC can be described as a quadratic polynomial when SWC lower than
the threshold value 32.5%, however, both NEE and Reco were increased linearly
when SWC higher than this value. The optimal SWC for maximum NEE and Reco
was 24.6 % when SWC lower than 32.5%. The apparent temperature sensitivity of
ecosystem respiration (Q10) declined with the phenology progressed during the
growing season, and decreased with the increase in soil temperature (Ts) during the
non-growing. Peak daily sums of NEE, gross primary production (GPP), and Reco
were -5.27, 13.33, and 10.24 g C m-2 d-1, respectively. Integrated NEE, GPP, and
Reco over measured year were -156.4, 1164.3 and 1007.9 g C m-2, respectively.
The Zoige alpine meadow was a medium carbon sink in grassland ecosystems. |
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