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| Titel |
The Polar Vegetation Photosynthesis and Respiration Model: a parsimonious, satellite-data-driven model of high-latitude CO2 exchange |
| VerfasserIn |
K. A. Luus, J. C. Lin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 8, no. 8 ; Nr. 8, no. 8 (2015-08-27), S.2655-2674 |
| Datensatznummer |
250116512
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| Publikation (Nr.) |
 copernicus.org/gmd-8-2655-2015.pdf |
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| Zusammenfassung |
| We introduce the Polar Vegetation Photosynthesis and Respiration
Model (PolarVPRM), a remote-sensing-based approach for generating accurate, high-resolution (≥ 1 km2, 3 hourly) estimates of net ecosystem CO2 exchange
(NEE). PolarVPRM simulates NEE using polar-specific vegetation
classes, and by representing high-latitude influences on NEE, such as the influence of
soil temperature on subnivean respiration. We present
a description, validation and error analysis (first-order Taylor expansion)
of PolarVPRM, followed by an
examination of per-pixel trends (2001–2012) in model output
for the North American terrestrial region north of 55° N. PolarVPRM was
validated against eddy covariance (EC) observations from nine North American sites,
of which three were used in model calibration. Comparisons of EC NEE to NEE from
three models indicated that PolarVPRM displayed similar or better statistical
agreement with eddy covariance observations than existing models showed.
Trend analysis (2001–2012) indicated that warming air temperatures and drought
stress in forests increased growing season rates of respiration, and
decreased rates of net carbon uptake by vegetation when air temperatures exceeded
optimal temperatures for
photosynthesis. Concurrent increases in growing season length at Arctic
tundra sites allowed for increases in photosynthetic uptake over time by tundra
vegetation. PolarVPRM estimated that the North American high-latitude
region changed from a carbon source (2001–2004) to a carbon
sink (2005–2010) to again a source (2011–2012) in response
to changing environmental conditions. |
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