The land-atmosphere water flux in the tropics

Fisher Joshua B., Malhi Yadvinder, Bonal Damien, Da Rocha Humberto R., De Araujo Alessandro C., Gamo Minoru, Goulden Michaël L., Hirano Takashi, Huete Alfredo R., Kondo Hiroaki, Kumagai Tomo'Omi, Loescher Henry W., Miller Scott, Nobre Antonio, Nouvellon Yann, Oberbauer Steven F., Panuthai Samreong, Roupsard Olivier, Saleska Scott, Tanaka Katsunori, Tanaka Nobuaki, Tu Kevin P., Von Randow Celso. 2009. The land-atmosphere water flux in the tropics. Global Change Biology, 15 (11) : 2694-2714.

Quartile : Outlier, Sujet : ENVIRONMENTAL SCIENCES / Quartile : Q1, Sujet : BIODIVERSITY CONSERVATION / Quartile : Q1, Sujet : ECOLOGY

Résumé : Tropical vegetation is a major source of global land surface evapotranspiration, and can thus play a major role in global hydrological cycles and global atmospheric circulation. Accurate prediction of tropical evapotranspiration is critical to our understanding of these processes under changing climate. We examined the controls on evapotranspiration in tropical vegetation at 21 pan-tropical eddy covariance sites, conducted a comprehensive and systematic evaluation of 13 evapotranspiration models at these sites, and assessed the ability to scale up model estimates of evapotranspiration for the test region of Amazonia. Net radiation was the strongest determinant of evapotranspiration (mean evaporative fraction was 0.72) and explained 87% of the variance in monthly evapotranspiration across the sites. Vapor pressure deficit was the strongest residual predictor (14%), followed by normalized difference vegetation index (9%), precipitation (6%) and wind speed (4%). The radiation-based evapotranspiration models performed best overall for three reasons: (1) the vegetation was largely decoupled from atmospheric turbulent transfer (calculated from X decoupling factor), especially at the wetter sites; (2) the resistance-based models were hindered by difficulty in consistently characterizing canopy (and stomatal) resistance in the highly diverse vegetation; (3) the temperature-based models inadequately captured the variability in tropical evapotranspiration. We evaluated the potential to predict regional evapotranspiration for one test region: Amazonia. We estimated an Amazonia-wide evapotranspiration of 1370mmyr_1, but this value is dependent on assumptions about energy balance closure for the tropical eddy covariance sites; a lower value (1096mmyr_1) is considered in discussion on the use of flux data to validate and interpolate models.

Mots-clés Agrovoc : végétation, bilan hydrique, évapotranspiration

Mots-clés géographiques Agrovoc : Amérique du Sud, Asie du Sud-Est, Afrique, Océanie, Amazonie

Classification Agris : F62 - Physiologie végétale - Croissance et développement
P10 - Ressources en eau et leur gestion
U10 - Informatique, mathématiques et statistiques

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

Auteurs et affiliations

• Fisher Joshua B., OUCE (GBR)
• Malhi Yadvinder, OUCE (GBR)
• Bonal Damien, INRA (GUF)
• Da Rocha Humberto R., USP (BRA)
• De Araujo Alessandro C., INPA (BRA)
• Gamo Minoru, National Institute of Advanced Industrial Science and Technology (JPN)
• Goulden Michaël L., UC (USA)
• Hirano Takashi, Hokkaido University (JPN)
• Huete Alfredo R., University of Arizona (USA)
• Kondo Hiroaki, National Institute of Advanced Industrial Science and Technology (JPN)
• Kumagai Tomo'Omi, Kyushu University (JPN)
• Loescher Henry W., Oregon State University (USA)
• Miller Scott, State University of New York (USA)
• Nobre Antonio, INPA (BRA)
• Nouvellon Yann, CIRAD-PERSYST-UPR Ecosystèmes de plantations (BRA)
• Oberbauer Steven F., Florida International University (USA)
• Panuthai Samreong, National Parks-Wildlife and plant Conservation Department (THA)
• Roupsard Olivier, CIRAD-PERSYST-UPR Ecosystèmes de plantations (CRI)
• Saleska Scott, University of Arizona (USA)
• Tanaka Katsunori, Frontier Research Center for Global Change (JPN)
• Tanaka Nobuaki, University of Tokyo (JPN)
• Tu Kevin P., UC (USA)
• Von Randow Celso, INPE (BRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/551936/)

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