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| Titel |
Distinguishing the drivers of trends in land carbon fluxes and plant volatile emissions over the past 3 decades |
| VerfasserIn |
X. Yue, N. Unger, Y. Zheng |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 20 ; Nr. 15, no. 20 (2015-10-27), S.11931-11948 |
| Datensatznummer |
250120124
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| Publikation (Nr.) |
 copernicus.org/acp-15-11931-2015.pdf |
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| Zusammenfassung |
| The terrestrial biosphere has experienced dramatic changes in recent decades.
Estimates of historical trends in land carbon fluxes remain uncertain because
long-term observations are limited on the global scale. Here, we use the Yale
Interactive terrestrial Biosphere (YIBs) model to estimate decadal trends in
land carbon fluxes and emissions of biogenic volatile organic compounds
(BVOCs) and to identify the key drivers for these changes during 1982–2011.
Driven by hourly meteorology from WFDEI (WATCH forcing data methodology
applied to ERA-Interim data), the model simulates an increasing trend of
297 Tg C a−2 in gross primary productivity (GPP) and 185 Tg
C a−2 in the net primary productivity (NPP). CO2 fertilization is
the main driver for the flux changes in forest ecosystems, while meteorology
dominates the changes in grasslands and shrublands. Warming boosts summer GPP
and NPP at high latitudes, while drought dampens carbon uptake in tropical
regions. North of 30° N, increasing temperatures induce a
substantial extension of 0.22 day a−1 for the growing season; however,
this phenological change alone does not promote regional carbon uptake and
BVOC emissions. Nevertheless, increases of leaf area index at peak season
accounts for ~ 25 % of the trends in GPP and isoprene emissions at
the northern lands. The net land sink shows statistically insignificant
increases of only 3 Tg C a−2 globally because of simultaneous
increases in soil respiration. Global BVOC emissions are calculated using two
schemes. With the photosynthesis-dependent scheme, the model predicts
increases of 0.4 Tg C a−2 in isoprene emissions, which are mainly
attributed to warming trends because CO2 fertilization and inhibition
effects offset each other. Using the MEGAN (Model of Emissions of Gases and
Aerosols from Nature) scheme, the YIBs model simulates global reductions of
1.1 Tg C a−2 in isoprene and 0.04 Tg C a−2 in monoterpene
emissions in response to the CO2 inhibition effects. Land use change
shows limited impacts on global carbon fluxes and BVOC emissions, but there
are regional contrasting impacts over Europe (afforestation) and China
(deforestation). |
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