Mecanismos de controle da variação sazonal da transpiração de uma floresta tropical no nordeste da amazônia

Filho, José Danilo da Costa Souza; Ribeiro, Aristides; Costa, Marcos Heil; Cohen, Julia

doi:10.1590/s0044-59672005000200012

Cited by 23 publications

(22 citation statements)

References 5 publications

(4 reference statements)

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“…With this typical seasonal variation, during the rainy season g a is generally greater, and therefore changes in atmospheric variable will also cause different responses of g a for each study site. This seasonal trend is the same for other work done in the Amazon region (Souza Filho et al, 2005;Vourtilis et al, 2008).…”

Section: Conductance Aerodynamicssupporting

confidence: 88%

“…The coefficient Ω of decoupling ranges between 0 and 1 (Wullschleger et al, 2000;Han et al, 2011). A Ω value closer to 1 indicates that transpiration is more dependent on the radiation balance; Ω values closer to 0 indicate that transpiration is more greatly controlled by the prevailing weather conditions that affect the physiological control of plants (Souza Filho et al, 2005).…”

Section: Calculation Of Et and Surface Variablesmentioning

confidence: 99%

“…Since the study area is surrounded by a larger area with intense human disturbance, the value for g s in Vourlitis et al (2002) was lower than that found in the current study in the TNF. Thus, the conductance of the canopy surface features of the exchange process with the atmosphere is controlled at various times by biotic and abiotic factors (Souza Filho et al, 2005).…”

Section: Surface Conductancementioning

confidence: 99%

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Evapotranspiration and control mechanisms in managed Amazonian forest in, Par, Brazil

Aguiar¹,

Oliveira²,

Beldini³

et al. 2017

Afr. J. Agric. Res.

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This work examines whether management causes changes in evapotranspiration (ET) surface conductance (g s ), aerodynamic conductance (g a ) and the decoupling factor (Ω) in managed and natural forest sites in a tropical rain forest in the Amazon. The study was conducted in the Tapajós National Forest (FNT) in managed (logged) and natural (unlogged) forests, which have micrometeorological towers for data capture. For ET estimation, the Penman-Monteith (PM) and Eddy Covariance (EC) equations were used. The models were significantly different only for unlogged ( . Each area has different characteristics for the surface variables, g a , g s and Ω, and therefore the sites were different from each other for the study variables. However, logged ET did not differ for the PM, while EC decreased in the year after the management intervention, and was then followed by an increase.

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Section: Conductance Aerodynamicssupporting

confidence: 88%

Section: Calculation Of Et and Surface Variablesmentioning

confidence: 99%

Section: Surface Conductancementioning

confidence: 99%

See 1 more Smart Citation

Evapotranspiration and control mechanisms in managed Amazonian forest in, Par, Brazil

Aguiar¹,

Oliveira²,

Beldini³

et al. 2017

Afr. J. Agric. Res.

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“…They used meteorological data from Caxiuanã, in Northeast Amazonia, to calculate the aerodynamic and surface conductance and the decoupling factor proposed by Jarvis and McNaughton (1986) during dry and wet periods. During the wet period surface conductance is higher than during the dry period (Souza Filho et al, 2005). On the other hand, VPD, aerodynamic conductance, and solar radiation are higher during the dry period.…”

Section: Introductionmentioning

confidence: 80%

“…Previous studies in the Amazon region have identified that evapotranspiration is directly connected to available energy, but also to aerodynamic transport mechanisms and biological control of transpiration, and that these controls vary according to the vegetation type or depending on periods of seasonal water deficits (e.g. Souza Filho et al, 2005, Hasler and Avissar, 2007, Costa et al, 2010, Von Randow et al, 2012, Christoffersen et al, 2014. Hasler and Avissar (2007) analyzed the seasonality of evapotranspiration in 8 sites in Amazonia; three of them are the K34, Rebio Jaru and FNS sites.…”

Section: Resultsmentioning

confidence: 99%

Analysis of biological and meteorological controls of evapotranspiration in pristine forests and a pasture site in Amazonia

Paulino¹,

Randow²,

Randow³

2017

Rev. ambiente água

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This work studied the behavior and seasonality of evapotranspiration influenced by biotic and abiotic factors through analysis of diurnal variation of aerodynamic resistance (ra), stomatal resistance (rs) and decoupling factor (Ω). This index was proposed by Jarvis and McNaughton (1986) as an indicative of the control of these resistances on the evapotranspiration of vegetation. Selection of representative data from wet and dry seasons from a primary forest in Central Amazonia and a primary forest and a pasture sites in Southwestern Amazonia had shown that: (i) ra is about 20 s.m-1 in both forests in both seasons, and ranges from 70 to 100 s.m-1 in the pasture site; (ii) rs varies both throughout the day and seasonally, with medians increasing from 40 in the morning, to 150 s.m-1 in late afternoon, in the wet season in the forests and from 50 to 160 s.m-1 in the pasture. These values increase in the dry season, with the forests rs ranging from 50 up to 500 s.m-1 and pasture rs starting from 140 s.m‑1 and reaching up to more than 1800 s.m-1 in the dry afternoons; (iii) Ω ranges from 0.5 to 0.8 during the wet season, and reduces to values below 0.5 in the afternoons during the dry season, indicating that, although a strong influence of net radiation in the evaporative loss is present, to a large extent the evapotranspiration fluxes are coupled to the biotic control of stomatal closure in the vegetation, especially in the pasture and during dry periods.

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Analysis of the energy balance and CO2 flow under the influence of the seasonality of climatic elements in a mangrove ecosystem in Eastern Amazon

et al. 2021

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An unprecedented study was carried out in a mangrove ecosystem in the northeastern coast of the Brazilian Amazon to understand the behavior of climatic elements in a year with the occurrence of El Niño (2015), associated with the seasonal function source/sink of CO2 by the ecosystem. Global radiation (Rg), net radiation (Rn), temperature, relative humidity, precipitation, horizontal wind speed and direction, as well as turbulent flows of sensible heat (H), latent heat (LE), and carbon (f_CO2) were recorded using eddy covariance, a system for studying turbulent flows of heat and gases in the atmosphere. We observed a drastic reduction in rainfall volumes, which accounts for 63.7% of the expected total according to the region’s climatology. Regarding f_ CO2, the highest values of photosynthesis, autotrophic, and heterotrophic respiration of the ecosystem occurred in the wet season due to precipitation, ideal photosynthetically active radiation, lower soil salinity, and higher NDVI of the ecosystem. In the 2nd semester of the year, we observed that the decrease in cloudiness, causing a higher radiation supply in the forest canopy, accompanied by a reduction in precipitation and an increase in the value of H and soil salinity, favored the increase of foliar abscission by the dominant genus Rhizophora and Avicennia, thus influencing the reduction of magnitudes of carbon source/sink functions in the ecosystem during this season, even on high tide days.

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Mecanismos de controle da variação sazonal da transpiração de uma floresta tropical no nordeste da amazônia

Cited by 23 publications

References 5 publications

Evapotranspiration and control mechanisms in managed Amazonian forest in, Par, Brazil

Evapotranspiration and control mechanisms in managed Amazonian forest in, Par, Brazil

Analysis of biological and meteorological controls of evapotranspiration in pristine forests and a pasture site in Amazonia

Analysis of the energy balance and CO2 flow under the influence of the seasonality of climatic elements in a mangrove ecosystem in Eastern Amazon

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