Data/hora: 03/06/2024 01:00:09

Biblioteca(s): | Embrapa Amazônia Oriental.
Data corrente: | 30/09/2014
Data da última atualização: | 19/10/2022
Autoria: | CHRISTOFFERSEN, B. O.; RESTREPO-COUPE, N.; ARAIN, M. A.; BAKER, I. T.; CESTARO, B. P.; CIAIS, P.; FISHER, J. B.; GALBRAITH, D.; GUAN, X.; GULDEN, L.; HURK, B. van den; ICHII, K.; IMBUZEIRO, H.; JAIN, A.; LEVINE, N.; MIGUEZ-MACHO, G.; POULTER, B.; ROBERTI, D. R.; SAKAGUCHI, K.; SAHOO, A.; SCHAEFER, K.; SHI, M.; VERBEECK, H.; YANG, Z.-L.; ARAUJO, A. C.; KRUIJT, B.; MANZI, A. O.; ROCHA, H. R. da; RANDOW, C. von; MUZA, M. N.; BORAK, J.; COSTA, M. H.; GONÇALVES, L. G. G. de; ZENG, X.; SALESKA, S. R.
Afiliação: | Bradley O. Christoffersen, University of Arizona; Natalia Restrepo-Coupe, University of Arizona / University of Technology, Sydney, Australia; M Altaf Arain, McMaster University; Ian T. Baker, Colorado State University; Bruno P. Cestaro, USP; Phillippe Ciais, LSCE CEA-CNRS-UVSQ, Orme des Merisiers; Joshua B. Fisher, California Institute of Technology; David Galbraith, University of Oxford / University of Leeds; Xiaodan Guan, The University of Texas at Austin; Lindsey Gulden, The University of Texas at Austin / ExxonMobil Upstream Research Company; Bart van den Hurk, Royal Netherlands Meteorological Institute (KNMI); Kazuhito Ichii, Fukushima University; Hewlley Imbuzeiro, UFV; Atul Jain, University of Illinois at Urbana-Champaign; Naomi Levine, Harvard University; Gonzalo Miguez-Macho, Universidade de Santiago de Compostela; Ben Poulter, Swiss Federal Research Institute WSL; Debora R. Roberti, UFSM; Koichi Sakaguchi, University of Arizona; Alok Sahoo, Center for Research on Environment and Water, IGES; Kevin Schaefer, University of Colorado at Boulder; Mingjie Shi, The University of Texas at Austin; Hans Verbeeck, Ghent University; Zong-Liang Yang, The University of Texas at Austin; ALESSANDRO CARIOCA DE ARAUJO, CPATU; Bart Kruijt, Wageningen University & Research Center; Antonio O. Manzi, INPA; Humberto R. da Rocha, USP; Celso von Randow, INPE; Michel N. Muza, University of Maryland, College Park, Hydrological Sciences Laboratory, NASA Goddard Space Flight Center; Jordan Borak, INPE; Marcos H. Costa, UFV; Luis Gustavo Gonçalves de Gonçalves, University of Maryland, College Park, Hydrological Sciences Laboratory, NASA Goddard Space Flight Center / INPE; Xubin Zeng, University of Arizona; Scott R. Saleska, University of Arizona.
Título: | Mechanisms of water supply and vegetation demand govern the seasonality and magnitude of evapotranspiration in Amazonia and Cerrado.
Ano de publicação: | 2014
Fonte/Imprenta: | Agricultural and Forest Meteorology, v. 191, p. 33-50, June 2014.
DOI: | 10.1016/j.agrformet.2014.02.008
Idioma: | Inglês
Conteúdo: | Evapotranspiration (E) in the Amazon connects forest function and regional climate via its role in precipitation recycling However, the mechanisms regulating water supply to vegetation and its demand for water remain poorly understood, especially during periods of seasonal water deficits In this study, we address two main questions: First, how do mechanisms of water supply (indicated by rooting depth and groundwater) and vegetation water demand (indicated by stomatal conductance and intrinsic water use efficiency) control evapotranspiration (E) along broad gradients of climate and vegetation from equatorial Amazonia to Cerrado, and second, how do these inferred mechanisms of supply and demand compare to those employed by a suite of ecosystem models? We used a network of eddy covariance towers in Brazil coupled with ancillary measurements to address these questions With respect to the magnitude and seasonality of E, models have much improved in equatorial tropical forests by eliminating most dry season water limitation, diverge in performance in transitional forests where seasonal water deficits are greater, and mostly capture the observed seasonal depressions in E at Cerrado However, many models depended universally on either deep roots or groundwater to mitigate dry season water deficits, the relative importance of which we found does not vary as a simple function of climate or vegetation In addition, canopy stomatal conductance (gs) regulates dry season vegetation demand for water at all except the wettest sites even as the seasonal cycle of E follows that of net radiation In contrast, some models simulated no seasonality in gs, even while matching the observed seasonal cycle of E. We suggest that canopy dynamics mediated by leaf phenology may play a significant role in such seasonality, a process poorly represented in models Model bias in gs and E, in turn, was related to biases arising from the simulated light response (gross primary productivity, GPP) or the intrinsic water use efficiency of photosynthesis (iWUE). We identified deficiencies in models which would not otherwise be apparent based on a simple comparison of simulated and observed rates of E. While some deficiencies can be remedied by parameter tuning, in most models they highlight the need for continued process development of belowground hydrology and in particular, the biological processes of root dynamics and leaf phenology, which via their controls on E, mediate vegetation-climate feedbacks in the tropics.
Thesagro: | Água; Cerrado; Evapotranspiração; Floresta Tropical.
Thesaurus Nal: | Amazonia.
Categoria do assunto: | P Recursos Naturais, Ciências Ambientais e da Terra
Registro original: | Embrapa Amazônia Oriental (CPATU)
Exemplares: | CPATU - (50190-1) - UPC - AP - DD - 4366 -  - 4366 - DIS