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Registro Completo |
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Biblioteca(s): |
Embrapa Cerrados. |
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Data corrente: |
12/01/2000 |
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Data da última atualização: |
12/01/2000 |
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Autoria: |
RANSON, K. J. |
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Título: |
A study of the angular reflectance characteristics of corn and soybean canopies. |
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Ano de publicação: |
1983 |
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Fonte/Imprenta: |
[West Lafayette]: Purdue University, 1983. |
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Páginas: |
168p. |
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Idioma: |
Inglês |
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Notas: |
Ph.D. Thesis. |
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Conteúdo: |
Understanding the characteristic of vegetation canopy reflectance is important if remotely sensed data is to be fully exploited to monitore the amount and status of agricultural resources. Since vegetation canopies are not simple Lambertian reflectors the affects of ilumination and viewing geometry must be understood to enhance the interpretation of the data. In this study the diurnal and seasonal directional reflectance characteristics of two important agricultural crops: corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) were examined. Spectral reflectance factor (RF), agronomic and biophysical measurements were acquired on three dates during 1980 for soybeans and on five dates in 1982 for corn over a wide range of sun and view angles. A pronounced sun-view angle effect on soybean canopy RF was observed, especially in the 0.6 - 0.7 [micron]m (red) wavelength band for canopies with well defined row structure Near infrared (near-IR) RF and the transformed variable greenness showed a less noticeable dependence for both incomplete and complete canopies. The effect of sun angle was greatest for view directions perpendicular to the canopy rows. Analysis of the data for apparent Lambertian behavior yielded very few off- nadir view angles that approximated straigth down measurements for the red band, while near-IR and greenness had extended off-nadir view angle ranges. A geometric optics model was developed to examine the effect of shadows on the red band RF for incomplete soybean canopies. Comparison of modeled and measured results indicated that for nadir view the model explainde up to 95% of the variation in the data. A solar zenith angle dependence for visible, near-IR and middle-IR RFs was noted for corn canopies with a low leaf area index (LAI). A decrease in teh spectral contrast between vegetation and soil due to shadows was cited as the cause of the dependence. Sun angle dependence was least for canopies with higher LAIs. RFs were maximized for coincident sun and view angles and maximized when the sensor view was towards the sun. Evaluation of three linear transformations (greenness, near-IR/red ratio and normalized difference) suggestes they may be useful for correcting the sun angle dependence for nadir acquired data. A strong dependence with view angle was noted for all three transformations for low LAI canopies. Greenness and near-IR/red ratio varied with view zenith angle, normalized difference did not. The asymptotic nature of normalized difference as LAI increases was cited as the reason for the lack of variation with view angle. MenosUnderstanding the characteristic of vegetation canopy reflectance is important if remotely sensed data is to be fully exploited to monitore the amount and status of agricultural resources. Since vegetation canopies are not simple Lambertian reflectors the affects of ilumination and viewing geometry must be understood to enhance the interpretation of the data. In this study the diurnal and seasonal directional reflectance characteristics of two important agricultural crops: corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) were examined. Spectral reflectance factor (RF), agronomic and biophysical measurements were acquired on three dates during 1980 for soybeans and on five dates in 1982 for corn over a wide range of sun and view angles. A pronounced sun-view angle effect on soybean canopy RF was observed, especially in the 0.6 - 0.7 [micron]m (red) wavelength band for canopies with well defined row structure Near infrared (near-IR) RF and the transformed variable greenness showed a less noticeable dependence for both incomplete and complete canopies. The effect of sun angle was greatest for view directions perpendicular to the canopy rows. Analysis of the data for apparent Lambertian behavior yielded very few off- nadir view angles that approximated straigth down measurements for the red band, while near-IR and greenness had extended off-nadir view angle ranges. A geometric optics model was developed to examine the effect of shadows on the red band RF for incomplete s... Mostrar Tudo |
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Palavras-Chave: |
Copa; Maize; Reflectancia; Spectrometry. |
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Thesagro: |
Espectrometria; Glycine Max; Iluminação; Milho; Sensoriamento Remoto; Soja; Zea Mays. |
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Thesaurus Nal: |
canopy; lighting; reflectance; remote sensing; soybeans. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 03395nam a2200325 a 4500
001 1563857
005 2000-01-12
008 1983 bl uuuu m 00u1 u #d
100 1 $aRANSON, K. J.
245 $aA study of the angular reflectance characteristics of corn and soybean canopies.
260 $a[West Lafayette]: Purdue University$c1983
300 $a168p.
500 $aPh.D. Thesis.
520 $aUnderstanding the characteristic of vegetation canopy reflectance is important if remotely sensed data is to be fully exploited to monitore the amount and status of agricultural resources. Since vegetation canopies are not simple Lambertian reflectors the affects of ilumination and viewing geometry must be understood to enhance the interpretation of the data. In this study the diurnal and seasonal directional reflectance characteristics of two important agricultural crops: corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) were examined. Spectral reflectance factor (RF), agronomic and biophysical measurements were acquired on three dates during 1980 for soybeans and on five dates in 1982 for corn over a wide range of sun and view angles. A pronounced sun-view angle effect on soybean canopy RF was observed, especially in the 0.6 - 0.7 [micron]m (red) wavelength band for canopies with well defined row structure Near infrared (near-IR) RF and the transformed variable greenness showed a less noticeable dependence for both incomplete and complete canopies. The effect of sun angle was greatest for view directions perpendicular to the canopy rows. Analysis of the data for apparent Lambertian behavior yielded very few off- nadir view angles that approximated straigth down measurements for the red band, while near-IR and greenness had extended off-nadir view angle ranges. A geometric optics model was developed to examine the effect of shadows on the red band RF for incomplete soybean canopies. Comparison of modeled and measured results indicated that for nadir view the model explainde up to 95% of the variation in the data. A solar zenith angle dependence for visible, near-IR and middle-IR RFs was noted for corn canopies with a low leaf area index (LAI). A decrease in teh spectral contrast between vegetation and soil due to shadows was cited as the cause of the dependence. Sun angle dependence was least for canopies with higher LAIs. RFs were maximized for coincident sun and view angles and maximized when the sensor view was towards the sun. Evaluation of three linear transformations (greenness, near-IR/red ratio and normalized difference) suggestes they may be useful for correcting the sun angle dependence for nadir acquired data. A strong dependence with view angle was noted for all three transformations for low LAI canopies. Greenness and near-IR/red ratio varied with view zenith angle, normalized difference did not. The asymptotic nature of normalized difference as LAI increases was cited as the reason for the lack of variation with view angle.
650 $acanopy
650 $alighting
650 $areflectance
650 $aremote sensing
650 $asoybeans
650 $aEspectrometria
650 $aGlycine Max
650 $aIluminação
650 $aMilho
650 $aSensoriamento Remoto
650 $aSoja
650 $aZea Mays
653 $aCopa
653 $aMaize
653 $aReflectancia
653 $aSpectrometry
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Registro original: |
Embrapa Cerrados (CPAC) |
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Registro Completo
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Biblioteca(s): |
Embrapa Soja. |
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Data corrente: |
20/10/2010 |
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Data da última atualização: |
15/02/2012 |
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Tipo da produção científica: |
Artigo em Anais de Congresso |
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Autoria: |
FERREIRA, P. R. S.; FORNAROLLI, D. A.; SANTOS, B. C.; GAZZIERO, D. L. P.; RODRIGUES, B. N.; ALVES, A. P. F. |
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Afiliação: |
P. R. S. FERREIRA, Faculdade Integrado de Campo Mourão; DONIZETTI APARECIDO FORNAROLLI, Faculdade Integrado de Campo Mourão; B . C. SANTOS, Faculdade Integrado de Campo Mourão; DIONISIO LUIZ PISA GAZZIERO, CNPSO; B. N. RODRIGUES, IAPAR; A. P. F. ALVES, UEM. |
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Título: |
Eficácia agronômica do uso de herbicidas no controle de Conyza bonariensis. |
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Ano de publicação: |
2010 |
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Fonte/Imprenta: |
In: CONGRESSO BRASILEIRO DA CIÊNCIA DAS PLANTAS DANINHAS, 27., 2010, Ribeirão Preto. Responsabilidade social e ambiental no manejo de plantas daninhas. Ribeirão Preto: SBCPD, 2010. p. 296-300. Trab. 65. 1 CD-ROM. CBCPD. |
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Idioma: |
Português |
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Thesagro: |
Erva daninha; Herbicida. |
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Thesaurus NAL: |
Herbicides; Weeds. |
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Categoria do assunto: |
W Química e Física |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/34249/1/31401.pdf
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Marc: |
LEADER 00764nam a2200205 a 4500
001 1864772
005 2012-02-15
008 2010 bl uuuu u00u1 u #d
100 1 $aFERREIRA, P. R. S.
245 $aEficácia agronômica do uso de herbicidas no controle de Conyza bonariensis.
260 $aIn: CONGRESSO BRASILEIRO DA CIÊNCIA DAS PLANTAS DANINHAS, 27., 2010, Ribeirão Preto. Responsabilidade social e ambiental no manejo de plantas daninhas. Ribeirão Preto: SBCPD, 2010. p. 296-300. Trab. 65. 1 CD-ROM. CBCPD.$c2010
650 $aHerbicides
650 $aWeeds
650 $aErva daninha
650 $aHerbicida
700 1 $aFORNAROLLI, D. A.
700 1 $aSANTOS, B. C.
700 1 $aGAZZIERO, D. L. P.
700 1 $aRODRIGUES, B. N.
700 1 $aALVES, A. P. F.
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