|
|
Registro Completo |
Biblioteca(s): |
Embrapa Territorial. |
Data corrente: |
10/06/2016 |
Data da última atualização: |
13/06/2016 |
Tipo da produção científica: |
Artigo em Periódico Indexado |
Autoria: |
MORTON, D. C.; RUBIO, J.; COOK, B. D.; GASTELLU-ETCHEGORRY, J-P; LONGO, M.; CHOI, H.; HUNTER, M.; KELLER, M. |
Afiliação: |
DOUGLAS C. MORTON, NASA; JEREMY RUBIO, NASA - Université de Toulouse; BRUCE D. COOK, NASA; JEAN-PHILIPPE GASTELLU-ETCHEGORRY, Université de Toulouse; MARCOS LONGO, BOLSISTA CNPM; HYEUNGU CHOI, Global Science & Technology Inc.; MARIA HUNTER, University of New Hampshire; MICHAEL KELLER, USDA Forest Service/ Pesquisador visitante CNPM. |
Título: |
Amazon forest structure generates diurnal and seasonal variability in light utilization. |
Ano de publicação: |
2016 |
Fonte/Imprenta: |
Biogeosciences, v. 13, p. 2195?2206, 2016. |
DOI: |
10.5194/bg-13-2195-2016 |
Idioma: |
Português |
Conteúdo: |
The complex three-dimensional (3-D) structure of tropical forests generates a diversity of light environments for canopy and understory trees. Understanding diurnal and seasonal changes in light availability is critical for interpreting measurements of net ecosystem exchange and improving ecosystem models. Here, we used the Discrete Anisotropic Radiative Transfer (DART) model to simulate leaf absorption of photosynthetically active radiation (lAPAR) for an Amazon forest. The 3-D model scene was developed from airborne lidar data, and local measurements of leaf reflectance, aerosols, and PAR were used to model lAPAR under direct and diffuse illumination conditions. Simulated lAPAR under clear-sky and cloudy conditions was corrected for light saturation effects to estimate light utilization, the fraction of lAPAR available for photosynthesis. Although the fraction of incoming PAR absorbed by leaves was consistent throughout the year (0.80?0.82), light utilization varied seasonally (0.67?0.74), with minimum values during the Amazon dry season. Shadowing and light saturation effects moderated potential gains in forest productivity from increasing PAR during dry-season months when the diffuse fraction from clouds and aerosols was low. Comparisons between DART and other models highlighted the role of 3-D forest structure to account for seasonal changes in light utilization. Our findings highlight how directional illumination and forest 3-D structure combine to influence diurnal and seasonal variability in light utilization, independent of further changes in leaf area, leaf age, or environmental controls on canopy photosynthesis. Changing illumination geometry constitutes an alternative biophysical explanation for observed seasonality in Amazon forest productivity without changes in canopy phenology. MenosThe complex three-dimensional (3-D) structure of tropical forests generates a diversity of light environments for canopy and understory trees. Understanding diurnal and seasonal changes in light availability is critical for interpreting measurements of net ecosystem exchange and improving ecosystem models. Here, we used the Discrete Anisotropic Radiative Transfer (DART) model to simulate leaf absorption of photosynthetically active radiation (lAPAR) for an Amazon forest. The 3-D model scene was developed from airborne lidar data, and local measurements of leaf reflectance, aerosols, and PAR were used to model lAPAR under direct and diffuse illumination conditions. Simulated lAPAR under clear-sky and cloudy conditions was corrected for light saturation effects to estimate light utilization, the fraction of lAPAR available for photosynthesis. Although the fraction of incoming PAR absorbed by leaves was consistent throughout the year (0.80?0.82), light utilization varied seasonally (0.67?0.74), with minimum values during the Amazon dry season. Shadowing and light saturation effects moderated potential gains in forest productivity from increasing PAR during dry-season months when the diffuse fraction from clouds and aerosols was low. Comparisons between DART and other models highlighted the role of 3-D forest structure to account for seasonal changes in light utilization. Our findings highlight how directional illumination and forest 3-D structure combine to influence diurnal an... Mostrar Tudo |
Thesaurus Nal: |
Tropical forests. |
Categoria do assunto: |
P Recursos Naturais, Ciências Ambientais e da Terra |
URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/144318/1/4729.pdf
|
Marc: |
LEADER 02479naa a2200229 a 4500 001 2046806 005 2016-06-13 008 2016 bl uuuu u00u1 u #d 024 7 $a10.5194/bg-13-2195-2016$2DOI 100 1 $aMORTON, D. C. 245 $aAmazon forest structure generates diurnal and seasonal variability in light utilization.$h[electronic resource] 260 $c2016 520 $aThe complex three-dimensional (3-D) structure of tropical forests generates a diversity of light environments for canopy and understory trees. Understanding diurnal and seasonal changes in light availability is critical for interpreting measurements of net ecosystem exchange and improving ecosystem models. Here, we used the Discrete Anisotropic Radiative Transfer (DART) model to simulate leaf absorption of photosynthetically active radiation (lAPAR) for an Amazon forest. The 3-D model scene was developed from airborne lidar data, and local measurements of leaf reflectance, aerosols, and PAR were used to model lAPAR under direct and diffuse illumination conditions. Simulated lAPAR under clear-sky and cloudy conditions was corrected for light saturation effects to estimate light utilization, the fraction of lAPAR available for photosynthesis. Although the fraction of incoming PAR absorbed by leaves was consistent throughout the year (0.80?0.82), light utilization varied seasonally (0.67?0.74), with minimum values during the Amazon dry season. Shadowing and light saturation effects moderated potential gains in forest productivity from increasing PAR during dry-season months when the diffuse fraction from clouds and aerosols was low. Comparisons between DART and other models highlighted the role of 3-D forest structure to account for seasonal changes in light utilization. Our findings highlight how directional illumination and forest 3-D structure combine to influence diurnal and seasonal variability in light utilization, independent of further changes in leaf area, leaf age, or environmental controls on canopy photosynthesis. Changing illumination geometry constitutes an alternative biophysical explanation for observed seasonality in Amazon forest productivity without changes in canopy phenology. 650 $aTropical forests 700 1 $aRUBIO, J. 700 1 $aCOOK, B. D. 700 1 $aGASTELLU-ETCHEGORRY, J-P 700 1 $aLONGO, M. 700 1 $aCHOI, H. 700 1 $aHUNTER, M. 700 1 $aKELLER, M. 773 $tBiogeosciences$gv. 13, p. 2195?2206, 2016.
Download
Esconder MarcMostrar Marc Completo |
Registro original: |
Embrapa Territorial (CNPM) |
|
Biblioteca |
ID |
Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
URL |
Voltar
|
|
Registro Completo
Biblioteca(s): |
Embrapa Amazônia Oriental. |
Data corrente: |
13/03/2008 |
Data da última atualização: |
10/02/2023 |
Tipo da produção científica: |
Artigo em Anais de Congresso / Nota Técnica |
Autoria: |
CARVALHO, E. J. M.; FREITAS, L. S.; VELOSO, C. A. C.; SOUZA, A. S.; EL-HUSNY, J. C.; VALENTE, M. A.; SOUZA, F. R. S. de; SILVEIRA FILHO, A.; LIRA, R. S. |
Afiliação: |
EDUARDO JORGE MAKLOUF CARVALHO, CPATU; L. S. FREITAS, pós-graduando UFRA; CARLOS ALBERTO COSTA VELOSO, CPATU; A. S. SOUZA, pós-graduando UFRA; JAMIL CHAAR EL HUSNY, CPATU; MOACIR AZEVEDO VALENTE, CPATU; F. R. S. SOUZA, pós-graduando UFRA; AUSTRELINO SILVEIRA FILHO, CPATU; ROBERTO SERTÃO LIRA, graduando UFRA. |
Título: |
Efeito de sistemas de manejo sobre o fósforo e o potássio em Latossolo vermelho amarelo do sudeste paraense. |
Ano de publicação: |
2007 |
Fonte/Imprenta: |
In: CONGRESSO BRASILEIRO DE CIÊNCIA DO SOLO, 31., 2007, Gramado. Conquistas e desafios da ciência do solo brasileira: anais. Porto Alegre: SBCS, 2007. |
Descrição Física: |
1 CD-ROM. |
Idioma: |
Português |
Palavras-Chave: |
Brasil; Pará; Redenção; Sudeste paraense. |
Thesagro: |
Cerrado; Fósforo; Latossolo Vermelho Amarelo; Manejo; Potássio; Solo. |
Thesaurus NAL: |
Amazonia. |
Categoria do assunto: |
-- |
URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/83967/1/trab-3134-2203.pdf
|
Marc: |
LEADER 01024nam a2200337 a 4500 001 1409044 005 2023-02-10 008 2007 bl uuuu u00u1 u #d 100 1 $aCARVALHO, E. J. M. 245 $aEfeito de sistemas de manejo sobre o fósforo e o potássio em Latossolo vermelho amarelo do sudeste paraense. 260 $aIn: CONGRESSO BRASILEIRO DE CIÊNCIA DO SOLO, 31., 2007, Gramado. Conquistas e desafios da ciência do solo brasileira: anais. Porto Alegre: SBCS$c2007 300 $c1 CD-ROM. 650 $aAmazonia 650 $aCerrado 650 $aFósforo 650 $aLatossolo Vermelho Amarelo 650 $aManejo 650 $aPotássio 650 $aSolo 653 $aBrasil 653 $aPará 653 $aRedenção 653 $aSudeste paraense 700 1 $aFREITAS, L. S. 700 1 $aVELOSO, C. A. C. 700 1 $aSOUZA, A. S. 700 1 $aEL-HUSNY, J. C. 700 1 $aVALENTE, M. A. 700 1 $aSOUZA, F. R. S. de 700 1 $aSILVEIRA FILHO, A. 700 1 $aLIRA, R. S.
Download
Esconder MarcMostrar Marc Completo |
Registro original: |
Embrapa Amazônia Oriental (CPATU) |
|
Biblioteca |
ID |
Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
Fechar
|
Nenhum registro encontrado para a expressão de busca informada. |
|
|