Evapotranspiration of deforested areas in central and southwestern Amazonia

Randow, Rita C. S. Von; Randow, Celso von; Hutjes, Ronald; Tomasella, Javier; Kruijt, B.

doi:10.1007/s00704-011-0570-1

Cited by 31 publications

(26 citation statements)

References 52 publications

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“…The combination of a negative feedback response between D A and g C with the overall radiative-aerodynamic coupling significantly dampens the variation of transpiration in PAS and TDF in the dry season, thus featuring increased biophysical control in these PFTs. These results are in agreement with von Randow et al (2012), who found enhanced biophysical control on λE T for the pasture during the dry season. For the wet season, evidence of minor biophysical control indicates the dominance of R N -driven equilibrium evaporation in these PFTs (Hasler and Avissar, 2007;da Rocha et al, 2009;Costa et al, 2010).…”

Section: Canopy Coupling G C and G A Vs Transpiration And Evaporasupporting

confidence: 82%

“…Previous studies in the Amazon Basin focused on developing an observational understanding of the biogeochemical cycling of energy, water, carbon, trace gases, and aerosols in Amazonia (Andreae et al, 2002;Malhi et al, 2002;da Rocha et al, 2009), model-based understanding of surface ecophysiological behavior and seasonality of λE Christoffersen et al, 2014), modeling the environmental controls on λE (Hasler and Avissar, 2007;Costa et al, 2010), understanding the seasonality of photosynthesis and of λE (da Rocha et al, 2004;, and the impact of land use on hydrometeorology (Roy and Avissar, 2002;von Randow et al, 2012). However, the combination of climatic and ecohydrological disturbances will significantly affect stomatal functioning, the partitioning of λE E − λE T , and carbon-water-climate interactions of tropical vegetation (Cox et al, 2000;Mercado et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Canopy-scale biophysical controls of transpiration and evaporation in the Amazon Basin

Mallick

Trebs

Boegh

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract. Canopy and aerodynamic conductances (g C and g A ) are two of the key land surface biophysical variables that control the land surface response of land surface schemes in climate models. Their representation is crucial for predicting transpiration (E T ) and evaporation (λE E ) flux components of the terrestrial latent heat flux (λE), which has important implications for global climate change and water resource management. By physical integration of radiometric surface temperature (T R ) into an integrated framework of the Penman-Monteith and Shuttleworth-Wallace models, we present a novel approach to directly quantify the canopyscale biophysical controls on λE T and λE E over multiple plant functional types (PFTs) in the Amazon Basin. Combining data from six LBA (Large-scale Biosphere-Atmosphere Experiment in Amazonia) eddy covariance tower sites and a T R -driven physically based modeling approach, we identified the canopy-scale feedback-response mechanism between g C , λE T , and atmospheric vapor pressure deficit (D A ), without using any leaf-scale empirical parameterizations for the modeling. The T R -based model shows minor biophysical control on λE T during the wet (rainy) seasons where λE T becomes predominantly radiation driven and net radiation (R N ) determines 75 to 80 % of the variances of λE T . However, biophysical control on λE T is dramatically increased during the dry seasons, and particularly the 2005 drought year, explaining 50 to 65 % of the variances of λE T , and indicates λE T to be substantially soil moisture driven during the rainfall deficit phase. Despite substantial differences in g A between forests and pastures, very similar canopy-atmosphere "coupling" was found in these two biomes due to soil moistureinduced decrease in g C in the pasture. This revealed the pragmatic aspect of the T R -driven model behavior that exhibits a high sensitivity of g C to per unit change in wetness as opposed to g A that is marginally sensitive to surface wetness variability. Our results reveal the occurrence of a significant hysteresis between λE T and g C during the dry season for the Published by Copernicus Publications on behalf of the European Geosciences Union. 4238 K. Mallick et al.: Canopy-scale biophysical controls of transpiration and evaporation in the Amazon Basin pasture sites, which is attributed to relatively low soil water availability as compared to the rainforests, likely due to differences in rooting depth between the two systems. Evaporation was significantly influenced by g A for all the PFTs and across all wetness conditions. Our analytical framework logically captures the responses of g C and g A to changes in atmospheric radiation, D A , and surface radiometric temperature, and thus appears to be promising for the improvement of existing land-surface-atmosphere exchange parameterizations across a range of spatial scales.

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Section: Canopy Coupling G C and G A Vs Transpiration And Evaporasupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Canopy-scale biophysical controls of transpiration and evaporation in the Amazon Basin

Mallick

Trebs

Boegh

et al. 2016

Hydrol. Earth Syst. Sci.

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“…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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“…In the dry season, the ET is more influenced by the amount of moisture stored in the soil during the previous rainy season than by rainfall events during the dry season. Furthermore, during the dry season, the stored soil moisture available for absorption by roots may be sufficient to keep the ET rate equal to or even greater than that during the rainy season (Shuttleworth 1988, Nepstad et al 1994, Malhi et al 2002, Sommer et al 2002, Souza Filho et al 2005, Negrón Juárez et al 2007, Von Randow et al 2011. Thus this suggest that in the dry season, …”

Section: Summary Of Previous Workmentioning

confidence: 98%

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon

Júnior

Souza

Tavares

et al. 2017

An. Acad. Bras. Ciênc.

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This study estimated the reference evapotranspiration rate (ETo) for the Itacaiúnas River Watershed (IRW), Eastern Amazonia, and measured the accuracy of eight empirical equations: Penman-Monteith (PM), Priestley-Taylor (PT), Hargreaves and Samani (HS), Camargo (CAM), Thornthwaite (TH), Hamon (HM), Kharrufa (KF) and Turc (TC) using monthly data from 1980 to 2013. In addition, it verifies the regional applicability to the IRW using a for the Marabá-PA station. The methods TC and PM (FAO56) presented the best results, which demonstrate that radiation and higher temperatures are the dominant drivers in the Evapotranspiration process, while relative humidity and wind speed have a much smaller impact. The temporal and spatial variability of ETo for IRW show has strong seasonality, increasing during the dry season and decreasing during the rainy season. The statistical analyses at 1% level of significance, indicates that there is no correlation of the residuals between the dry and rainy seasons, and test of the physical parameters such as mean temperature, solar radiation and relative air humidity explains the variations of ETo.

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Evapotranspiration of deforested areas in central and southwestern Amazonia

Cited by 31 publications

References 52 publications

Canopy-scale biophysical controls of transpiration and evaporation in the Amazon Basin

Canopy-scale biophysical controls of transpiration and evaporation in the Amazon Basin

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

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon

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