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| Titel |
Relationships between photosynthesis and formaldehyde as a probe of isoprene emission |
| VerfasserIn |
Y. Zheng, N. Unger, M. P. Barkley, X. Yue |
| 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. 15 ; Nr. 15, no. 15 (2015-08-03), S.8559-8576 |
| Datensatznummer |
250119942
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| Publikation (Nr.) |
 copernicus.org/acp-15-8559-2015.pdf |
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| Zusammenfassung |
| Atmospheric oxidation of isoprene emission from land plants affects
radiative forcing of global climate change. There is an urgent need to
understand the factors that control isoprene emission variability on large
spatiotemporal scales but such direct observations of isoprene emission do
not exist. Two readily available global-scale long-term observation-based
data sets hold information about surface isoprene activity: gross primary
productivity (GPP) and tropospheric formaldehyde column variability (HCHOv).
We analyze multi-year seasonal linear correlations between observed GPP and
HCHOv. The observed GPP–HCHOv correlation patterns are used to evaluate a
global Earth system model that embeds three alternative leaf-level isoprene
emission algorithms. GPP and HCHOv are decoupled in the summertime in the southeast
US (r=−0.03). In the Amazon, GPP and HCHOv are weakly correlated in
March-April-May (MAM), correlated in June-July-August (JJA) and weakly
anticorrelated in September-October-November (SON). Isoprene emission
algorithms that include soil moisture dependence demonstrate greater skill
in reproducing the observed interannual seasonal GPP–HCHOv correlations in
the southeast US and the Amazon. In isoprene emission models that include
soil moisture dependence, isoprene emission is correlated with
photosynthesis and anticorrelated with HCHOv. In an isoprene emission model
without soil moisture dependence, isoprene emission is anticorrelated with
photosynthesis and correlated with HCHOv. Long-term monitoring of isoprene
emission, soil moisture and meteorology is required in water-limited
ecosystems to improve understanding of the factors controlling isoprene
emission and its representation in global Earth system models. |
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