Variação espacial e temporal da irradiância solar e da razão entre vermelho e vermelho - extremo que chegam ao solo em diferentes microhabitats na região de Tucuruí - PA

Goldman, Gustavo Henrique; Plana-Fattori, Artemio; Januário, Mauro

doi:10.1590/1809-43921989191248

Cited by 4 publications

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“…Values between 0.4 and 0.5 are frequently found, but R:FR ratios can even reach minimums of 0.1 (Goldman et al . 1989; Capers & Chazdon 2004). Specifically, Salazar et al .…”

Section: Discussionmentioning

confidence: 99%

“…Understory R:FR ratios are spatially and temporally variable even on a daily basis in forest environments. Values between 0.4 and 0.5 are frequently found, but R:FR ratios can even reach minimums of 0.1 (Goldman et al 1989;Capers & Chazdon 2004). Specifically, Salazar et al (2012) found a R:FR average near 0.4 in the understory of an encroached savanna.…”

Section: Light Temperature and Seed Germinationmentioning

confidence: 99%

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Woody plant encroachment constrains regeneration of ground‐layer species in a neotropical savanna from seeds

et al. 2022

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Woody plants have been encroaching into savannas on a global scale. Global climatic changes, along with changes to disturbance regimes, are considered to be the main drivers of this process. Particularly, many formerly open physiognomies of the Brazilian savanna have become encroached by woody species over the course of a few decades under fire suppression. In this scenario, many typical savanna species of the groundlayer are reducing their above-ground presence, possibly due to change in environmental filtering as a result of encroachment. Consequently, at encroachment sites, changes to microhabitats occur, such as less incident light to the soil surface, reduced red:far-red ratios and soil surface temperatures, and increased litter deposition. These changes may hinder the regenerative capacity of ground-layer savanna species. This study investigated the role of encroachment-induced environmental changes as filters for the recruitment ability of ground-layer savanna species. We examined the germination and seedling emergence of 12 species under controlled conditions, simulating natural aspects of encroached and non-encroached sites of the Brazilian savanna. The germination and/or seedling emergence of all species examined were/was negatively affected by the simulated environmental filtering changes. Increased litter deposition reduced seedling emergence more than temperature and light affected germination. Filtering changes caused by woody encroachment represent a bottleneck for the regeneration from seeds of ground-layer savanna species. Filtering changes by woody encroachment is one of the underlying mechanism explaining changes in species presence in savannas, and it ultimately leads to positive feedback loops wherein woody encroachment begets more woody encroachment.

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“…Values between 0.4 and 0.5 are frequently found, but R:FR ratios can even reach minimums of 0.1 (Goldman et al . 1989; Capers & Chazdon 2004). Specifically, Salazar et al .…”

Section: Discussionmentioning

confidence: 99%

Section: Light Temperature and Seed Germinationmentioning

confidence: 99%

Woody plant encroachment constrains regeneration of ground‐layer species in a neotropical savanna from seeds

et al. 2022

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“…Apesar da importância da irradiância solar, os estudos que quantificam o fluxo de radiação solar que atinge a superfície ainda são poucos (Brinkmann et al, 1971;Costa Azevedo et al, 1974;Vila Nova et al, 1976, 1978,Feitosa et al, 1998, Pavão et al, 2014 e com pouca extensão temporal de suas medidas (por exemplo Culf et al, 1996). Além disso, são raros os artigos que possuem medidas das componentes direta (Almeida et al, 1979) e/ou difusa (Goldman et al, 1989). Recentemente, Macedo (2016) fez uma compilação completa destas informações já publicadas.…”

Section: Introductionunclassified

Variabilidade Temporal da Radiação Solar Durante o Experimento GOAmazon 2014/15

Macedo

Fisch

2018

Rev. bras. meteorol.

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ResumoO presente trabalho estudou a variabilidade temporal das 3 componentes da irradiância solar (global, direta e difusa) na região de Manacapuru, distante 66 km de Manaus-AM, dentro do âmbito do projeto GOAmazon 2014/15, analisando dados relativos aos anos de 2014 e 2015. Também foram analisados dados de cobertura de nuvens e precipitação do mesmo período. Observou-se, de modo geral, que os valores das frações de nuvens foram semelhantes entre os dois anos analisados, situando-se entre valores típicos de 20-25% (estação seca) e 35-40% (estação chuvosa). São apresentados valores típicos das irradiâncias solar global, direta e difusa para diferentes escalas de tempo (horárias e sazonal), bem como as variações destes valores entre os anos 2014-2015 (escala interanual). São também apresentados as interrelações destas 3 componentes para os valores médios horários e mensais e observa-se que as irradiâncias solar global e direta são diretamente relacionadas entre si e inversamente relacionadas com a contribuição difusa. Finalizando, é discutido como o evento EN 2015 impactou as medidas das 3 componentes da irradiância solar a superfície, associando com a menor ocorrência de nuvens/chuva e da presença maior de aerossóis. Palavras-chave: global, difusa, direta, cobertura de nuvens, medida direta. Temporal Variability of Solar Radiation During the GOAmazon 2014/15 Experiment AbstractThe present work studied the temporal variability of the three components of solar irradiation (global, direct and diffuse) at the Manacapuru region, 66 km distant from Manaus-AM, within the scope of the GOAmazon 2014/15 project, analyzing data for the years of 2014 and 2015. Also it was analyzed the cloud cover data and precipitation. In general, the cloud cover for both years were similar and their typical values are 20-25% (dry season) and 35-40% (wet period). The typical values of global, direct and diffuse solar irradiance were presented for different time scale (hourly and seasonal) as well as variations for the years 2014 and 2015 (interannual scale). The interrelationships amongst the 3 components for hourly and monthly values were presented and it can be noticed that global and direct solar irradiances were directly related although both were inversely correlated with the diffuse solar irradiance. Finally, the ENSO 2015 event was discussed and how it was impacted, the measurements as it had lower cloud cover and rain the higher aerosol concentration.

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“…Caracteriza-se por possuir elevado índice pluviométrico, sendo que a precipitação e a cobertura de nuvens são os elementos climáticos com maior variabilidade espacial e temporal na região tropical amazônica (Fisch et al, 1998). Estudos relacionados ao tempo e clima amazônicos foram realizados pela comunidade científica desde meados da década de 70, embora de forma isolada e pontual (Brinkmann et al, 1971;Costa Azevedo et al, 1974;Vila Nova et al, 1976;Almeida et al, 1979;Goldman et al, 1989;Marques Filho et al 2005;Marques et al, 2012).…”

Section: Introductionunclassified

Variabilidade Espacial da Radiação Solar na Região de Manaus - AM durante o Experimento GOAmazon 2014/15 (Spatial variability of solar radiation in Manaus-AM region during GOAmazon Experiment 2014/15)

Macedo

Fisch²

2017

Rev. Bras. Geog. Fis.

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Este trabalho realizou um estudo da variabilidade espacial em 2014 da irradiância solar na região de Manaus-AM, através de dados observacionais, inserido no Projeto GOAmazon 2014/15. Também, como forma complementar, foi realizada a análise da cobertura de nuvens, chuva e aerossóis e suas interrelações com a irradiância solar. Como resultado, observa-se que os menores valores médios da irradiância solar ocorreram na área urbana,o que é justificado, em parte pela urbanização que altera os fluxos envolvidos, diminuindo a irradiância solar à superfície. Os valores típicos são entre 400 e 600 Wm-2na estação chuvosa (fevereiro/março) com um desvio padrão de 200 e 380 Wm-2e entre 650 e 800 Wm-2na estação seca (agosto-setembro) com desvio padrão de 190 e 300 Wm-2. A B S T R A C T The solar radiation is an important climatic element in the Amazon region, as it has a strong impact for ecological (by the preservation of the biodiversity) and technological (as a renewable energy) areas. Consequently, this study contributes for these themes, conducting an observational study of the spatial variability of the solar irradiance for Manaus-AM area, with data collected during the project GOAmazon 2014/15. The cloud cover and rainfall and their relationships with solar radiation were also analysed. The maximum values observed for the wet season (february and march) are in the range 450 and 600 Wm-2 with high standart deviation (300 - 350 Wm-2 ), while they are in the range from 650 and 800 Wm-2 during the dry period (august - september) with lower standart deviation (200 - 300 Wm-2). These values are directly associated with cloud cover and rainfall. In general, the urban area (Manaus city) showed the low values of solar radiation at the surface compared with its neighborhood, inducing a horizontal gradient of clouds/rainfall and solar energy between the city and the semi rural areas. Keywords: piranometer, global solar radiation, cloud cover, total sky imager

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Variação espacial e temporal da irradiância solar e da razão entre vermelho e vermelho - extremo que chegam ao solo em diferentes microhabitats na região de Tucuruí - PA

Cited by 4 publications

References 1 publication

Woody plant encroachment constrains regeneration of ground‐layer species in a neotropical savanna from seeds

Woody plant encroachment constrains regeneration of ground‐layer species in a neotropical savanna from seeds

Variabilidade Temporal da Radiação Solar Durante o Experimento GOAmazon 2014/15

Variabilidade Espacial da Radiação Solar na Região de Manaus - AM durante o Experimento GOAmazon 2014/15 (Spatial variability of solar radiation in Manaus-AM region during GOAmazon Experiment 2014/15)

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