Measurements of net radiation absorbed by isolated acid lime trees (<i>Citrus latifolia</i>Tanaka)

Angelocci, Luiz Roberto; Nova, Nílson Augusto Villa; Filho, M. A. Coelho; Marin, Fábio Ricardo

doi:10.1080/14620316.2004.11511829

Cited by 11 publications

(26 citation statements)

References 9 publications

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“…To measure the fraction of Qg transmitted by the orange canopy ('τQg') a pyranometer LI-200 (LI-COR) was attached to a circular metal frame, component of a mobile system of measurement, rotating around the canopy, similar to that described by Angelocci et al (2004) and McNaughton et al (1992). By the movement of this system around the tree, the pyranometer turned horizontally around the trunk at a distance of 0.65 m at 3 rpm, performing a space-time sampling of solar radiation transmitted to below the canopy.…”

Section: Methodsmentioning

confidence: 99%

Área foliar e interceptação de radiação solar pela copa de uma laranjeira

Pilau

Angelocci

2015

Bragantia

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Leaf area changes affect solar radiation interception (K*), interception efficiency (ε int ) and extinction coefficient (k) of an orange tree top (cv. Pêra-Rio). In order to measure radiation transmitted through the crown a mobile sensor was horizontally installed below the crown and 0.65 m from the trunk, moving around it at 3 rpm. The model used for k determination (Monsi & Saeki theory) was assessed with independent data to estimate K*. With absence of leaves, it was detected an intense interference of trunk and branches on ε int , with a minimum value of 0.52. The results were also distinct in obtaining k, when the best fit was found with a quadratic rather than a linear equation, again influenced by woody structures. Simulation of K* using extinction coefficient (k) was statistically classified as good.

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Section: Methodsmentioning

confidence: 99%

Área foliar e interceptação de radiação solar pela copa de uma laranjeira

Pilau

Angelocci

2015

Bragantia

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“…Nas últimas décadas, com vistas à melhor compreensão do consumo de água e da fotossíntese na escala da planta, tem-se investido no estudo da interação da energia radiante em copas de espécies arbóreas que formam dosséis descontínuos (Angelocci et al, 2004;Green et al, 2001;Landsberg et al, 1975;McNaughton et al, 1992;Thorpe, 1978).…”

Section: Introductionunclassified

“…A medição direta do balanço de radiação da copa de arbóreas é relativamente complexa, como referendam as metodologias descritas por Landsberg et al (1975) e McNaughton et al (1992) e suas adaptações (Angelocci et al, 2004), exigindo estrutura específica e grande número de sensores nas determinações, além da superação de dificuldades originárias da geometria e da dimensão das copas.…”

Section: Introductionunclassified

Balanço de radiação de copas de cafeeiros em renques e suas relações com radiação solar global e saldo de radiação de gramado

Pilau¹,

Angelocci²

2014

Bragantia

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ResumoDevido à importância da quantificação da radiação solar interceptada e absorvida por plantas foram realizadas medidas do saldo de radiação (Rnc) de copas em um trecho de renque de cafeeiros, analisando-se o efeito de diferentes áreas foliares no renque e correlacionando-os com dados de radiação solar global (Qg) e saldo de radiação de gramado (Rn). Para a mensuração nos cafeeiros foi utilizado um sistema de integração espaço-temporal com saldo-radiômetros móveis. Os resultados evidenciam uma relação direta porém não proporcional entre Rnc e área foliar das plantas. As relações de Rnc com Qg são específicas para cada área foliar. Os dados não sustentam a hipótese de que o saldo de radiação normalizado por unidade de área foliar seja uma função linear do saldo de radiação de gramado.Palavras-chave: saldo de radiação, área foliar, variáveis meteorológicas, Coffea arabica L. Radiation balance of coffee tree tops in hedgerows and its relations with global solar and grass net radiations AbstractIntercepted solar radiation (ISR) is important for plant growth, development and energy fluxes. We used a mobile device carrying on eight net radiometers encompassing coffee plants aligned in hedgerows to measure Rnc. Measures of radiation balance over several coffee hedgerows (Rnc) were taken in order to analyze the effect of leaf area (LA) on ISR as well as its relationship with solar radiation (Qg) and grass net radiation (Rn). Results showed a direct relationship between LA, Rnc and Qg. However, these relations were not linear, which leads us to refute the hypothesis that the normalized Rnc in terms of leaf area would be a linear function of the grass net radiation.

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“…McNaughton et al (1992) developed a device, which they named "Whirligig", with eight net radiometers and sixteen PAR sensors fixed on a circular frame, rotating around a tree of Robinia pseudoacacia, allowing timespace integration of the radiation balance of the tree. The "Whirligig" technique has been used in some studies involving radiation balance of isolated trees (Green, 1993;Green et al, 1995;Green and McNaughton, 1997;Green et al, 2001;Angelocci et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Radiation balance of coffee hedgerows

Angelocci

Marin

Pilau

et al. 2008

Rev. bras. eng. agríc. ambient.

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The radiation balance of hedgerows is an important variable in studies of mass and energy exchanges between parcial ground cover crops and the atmosphere. This paper describes a device with eight net radiometers encompassing the plants of a hedgerow. The radiometers were moved along a length of hedgerow, in a continuous and reversible movement. The canopy net radiation in this length (Rnc) was found by integration of the measurements over the notional cylinder formed. The device showed good performance and provided reliable measurements of Rnc of coffee hedgerows, showing itselfto be an useful technique of measurement in field conditions. Good correlations between Rnc and global solar radiation, turfgrass and coffee crop net radiation were found in 15-min, daytime and 24-hr periods, allowing the possibility of estimating Rnc from these simple measurements. Beer’s law was also used to have an independent estimation of Rnc. A good agreement was found between values of Rnc estimated by this law of attenuation and those integrated by the device in periods of 15 min, with overestimation of 10%, whereas for values integrated over daytime periods the agreement was not satisfactory.

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Measurements of net radiation absorbed by isolated acid lime trees (Citrus latifoliaTanaka)

Cited by 11 publications

References 9 publications

Área foliar e interceptação de radiação solar pela copa de uma laranjeira

Área foliar e interceptação de radiação solar pela copa de uma laranjeira

Balanço de radiação de copas de cafeeiros em renques e suas relações com radiação solar global e saldo de radiação de gramado

Radiation balance of coffee hedgerows

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