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Vegetation dynamics and rainfall sensitivity of the Amazon.
Hilker, Thomas; Lyapustin, Alexei I; Tucker, Compton J; Hall, Forrest G; Myneni, Ranga B; Wang, Yujie; Bi, Jian; Mendes de Moura, Yhasmin; Sellers, Piers J.
Afiliação
  • Hilker T; College of Forestry, Corvallis, OR 97331; thomas.hilker@oregonstate.edu.
  • Lyapustin AI; Goddard Space Flight Center, NASA, Greenbelt, MD 20771;
  • Tucker CJ; Goddard Space Flight Center, NASA, Greenbelt, MD 20771;
  • Hall FG; Goddard Space Flight Center, NASA, Greenbelt, MD 20771; Joint Center for Earth System Technology, University of Maryland Baltimore County, Baltimore, MD 21228;
  • Myneni RB; Department of Earth and Environment, Boston University, Boston, MA 02215; and.
  • Wang Y; Goddard Space Flight Center, NASA, Greenbelt, MD 20771; Joint Center for Earth System Technology, University of Maryland Baltimore County, Baltimore, MD 21228;
  • Bi J; Department of Earth and Environment, Boston University, Boston, MA 02215; and.
  • Mendes de Moura Y; Divisão de Sensoriamento Remoto, Instituto Nacional de Pesquisas Espaciais, São José dos Campos, 12245-970 São Paulo State, Brazil.
  • Sellers PJ; Goddard Space Flight Center, NASA, Greenbelt, MD 20771;
Proc Natl Acad Sci U S A ; 111(45): 16041-6, 2014 Nov 11.
Article em En | MEDLINE | ID: mdl-25349419
We show that the vegetation canopy of the Amazon rainforest is highly sensitive to changes in precipitation patterns and that reduction in rainfall since 2000 has diminished vegetation greenness across large parts of Amazonia. Large-scale directional declines in vegetation greenness may indicate decreases in carbon uptake and substantial changes in the energy balance of the Amazon. We use improved estimates of surface reflectance from satellite data to show a close link between reductions in annual precipitation, El Niño southern oscillation events, and photosynthetic activity across tropical and subtropical Amazonia. We report that, since the year 2000, precipitation has declined across 69% of the tropical evergreen forest (5.4 million km(2)) and across 80% of the subtropical grasslands (3.3 million km(2)). These reductions, which coincided with a decline in terrestrial water storage, account for about 55% of a satellite-observed widespread decline in the normalized difference vegetation index (NDVI). During El Niño events, NDVI was reduced about 16.6% across an area of up to 1.6 million km(2) compared with average conditions. Several global circulation models suggest that a rise in equatorial sea surface temperature and related displacement of the intertropical convergence zone could lead to considerable drying of tropical forests in the 21st century. Our results provide evidence that persistent drying could degrade Amazonian forest canopies, which would have cascading effects on global carbon and climate dynamics.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Chuva / Mudança Climática / Pradaria / Floresta Úmida / Modelos Biológicos Tipo de estudo: Diagnostic_studies País/Região como assunto: America do sul / Brasil Idioma: En Revista: Proc Natl Acad Sci U S A Ano de publicação: 2014 Tipo de documento: Article País de publicação: Estados Unidos
Texto completo
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XML
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Chuva / Mudança Climática / Pradaria / Floresta Úmida / Modelos Biológicos Tipo de estudo: Diagnostic_studies País/Região como assunto: America do sul / Brasil Idioma: En Revista: Proc Natl Acad Sci U S A Ano de publicação: 2014 Tipo de documento: Article País de publicação: Estados Unidos