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| Titel |
Predicting the response of the Amazon rainforest to persistent drought conditions under current and future climates: a major challenge for global land surface models |
| VerfasserIn |
E. Joetzjer, C. Delire, Hervé Douville, P. Ciais, B. Decharme, R. Fisher, B. Christoffersen, J. C. Calvet, A. C. L. da Costa, L. V. Ferreira, P. Meir |
| 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 ; 7, no. 6 ; Nr. 7, no. 6 (2014-12-10), S.2933-2950 |
| Datensatznummer |
250115793
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| Publikation (Nr.) |
 copernicus.org/gmd-7-2933-2014.pdf |
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| Zusammenfassung |
| While a majority of global climate models project drier and longer dry
seasons over the Amazon under higher CO2 levels, large uncertainties
surround the response of vegetation to persistent droughts in both
present-day and future climates. We propose a detailed evaluation of the
ability of the ISBACC (Interaction Soil–Biosphere–Atmosphere Carbon Cycle) land surface model to capture drought effects on
both water and carbon budgets, comparing fluxes and stocks at two recent
throughfall exclusion (TFE) experiments performed in the Amazon. We also
explore the model sensitivity to different water stress functions (WSFs) and
to an idealized increase in CO2 concentration and/or temperature. In
spite of a reasonable soil moisture simulation, ISBACC struggles to
correctly simulate the vegetation response to TFE whose amplitude and timing
is highly sensitive to the WSF. Under higher CO2 concentrations, the
increased water-use efficiency (WUE) mitigates the sensitivity of ISBACC
to drought. While one of the proposed WSF formulations improves the response
of most ISBACC fluxes, except respiration, a parameterization of
drought-induced tree mortality is missing for an accurate estimate of the
vegetation response. Also, a better mechanistic understanding of the forest
responses to drought under a warmer climate and higher CO2
concentration is clearly needed. |
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