Manioc : Portail | resultats 1 - 20 pour la recherche: Richardson, Andrew D.

Éditeur(s) : HAL CCSD Wiley
Résumé : The intensification of the hydrological cycle, with an observed and modeled increase in drought incidence and severity, underscores the need to quantify drought effects on carbon cycling and the terrestrial sink. FLUXNET, a global network of eddy covariance towers, provides dense data streams of meteorological data, and through flux partitioning and gap filling algorithms, estimates of net ecosystem productivity (FNEP), gross ecosystem productivity (P), and ecosystem respiration (R). We analyzed the functional relationship of these three carbon fluxes relative to evaporative fraction (EF), an index of drought and site water status, using monthly data records from 238 micrometeorological tower sites distributed globally across 11 biomes. The analysis was based on relative anomalies of both EF and carbon fluxes and focused on drought episodes by biome and climatic season. Globally P was ≈50% more sensitive to a drought event than R. Network-wide drought-induced decreases in carbon flux averaged −16.6 and −9.3 g C m−2 month−1 for P and R, i.e., drought events induced a net decline in the terrestrial sink. However, in evergreen forests and wetlands drought was coincident with an increase in P or R during parts of the growing season. The most robust relationships between carbon flux and EF occurred during climatic spring for FNEP and in climatic summer for P and R. Upscaling flux sensitivities to a global map showed that spatial patterns for all three carbon fluxes were linked to the distribution of croplands. Agricultural areas exhibited the highest sensitivity whereas the tropical region had minimal sensitivity to drought. Combining gridded flux sensitivities with their uncertainties and the spatial grid of FLUXNET revealed that a more robust quantification of carbon flux response to drought requires additional towers in all biomes of Africa and Asia as well as in the cropland, shrubland, savannah, and wetland biomes globally.
ISSN: 1354-1013

hal-01032076
https://hal.archives-ouvertes.fr/hal-01032076
DOI : 10.1111/j.1365-2486.2009.01991.x

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Annuaire de la Guadeloupe et dépendances pour l'année 1904
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The English in the West Indies or the bow of Ulysses
Auteur(s) : Froude, James Anthony (1818-1894) Pearson, G.
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Annuaire de la Guadeloupe et dépendances. Année 1903
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La Méditerranée américaine : l'expansion des Etats-Unis dans la mer des Antilles
Auteur(s) : Crockaert, Jacques (1901-1949)
Auteurs secondaires : Jaspar, Henri (1870-1939)
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Personal narrative of travels to the equinoctial regions of America, during the years 1799-1804 / by Alexander von Humboldt and Aimé Bonpland ; translated from the French of Alexander von Humboldt and edited by Thomasina Ross. Volume 2
Auteur(s) : Bonpland, Aimé (1773-1858) Humboldt, Alexander von (1769-1859)
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The civil and natural History of Jamaica. In three parts. Containing, I. An accurate description of that island, its situation and soil ; with a brief account of its former and present State, Government, Revenues, Produce, and Trade. II. A history of the natural productions, including the various sorts of native fossils ; perfect and impercfect begetables ; quadrupedes, birds, fishes, reptiles and insects ; with their properties and uses in mechanics, diet, and physic. III. An account of the nature of climates in general, and their different effects upon the human body ; with a detail of the diseases arising from this source, particularly within the Tropics. In three dissertations. The whole illustrated with fifty copper-plates : in which the most curious productions are represented of the natural size, and delineated immediately from the objects
Auteur(s) : Browne, Patrick (1720-1790)
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Personal narrative of travels to the equinoctial regions of America, during the years 1799-1804 / by Alexander von Humboldt and Aimé Bonpland ; translated from the French of Alexander von Humboldt and edited by Thomasina Ross. Volume 1
Auteur(s) : Bonpland, Aimé (1773-1858) Humboldt, Alexander von (1769-1859)
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Géographie complète et universelle : illustrée de 50 gravures, 8 cartes, 5 planches et du portrait de l'auteur. Tome cinquième
Auteur(s) : Malte-Brun, Conrad (1775-1826)
Auteurs secondaires : Malte-Brun, Victor-Adolphe (1816-1889)
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