Cálculo da evapotranspiração real na Bacia Amazônica através do método aerológico

Marques, José Augusto Veiga da Costa; Salati, Enéas; Santos, Jesus Marden dos

doi:10.1590/1809-43921980102357

Cited by 27 publications

(12 citation statements)

References 2 publications

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“…In connection with the atmospheric water vapour and related studies, the accumulated 180 isotope data has been reviewed and this .so far confirms the existing conclusion (Marques et al 1979;1980) that spillage of excess water vapour from the basin finds its way S into central Brazil (Gat 1988). In connection with the atmospheric water vapour and related studies, the accumulated 180 isotope data has been reviewed and this .so far confirms the existing conclusion (Marques et al 1979;1980) that spillage of excess water vapour from the basin finds its way S into central Brazil (Gat 1988).…”

Section: Hydrological Cyclesupporting

confidence: 71%

Amazon bio-geosciences: Towards a synthesis through ?Amazonia I?

Vose

1989

GeoJournal

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Amazonia I" is a large multi-disciplinary project, now in its fourth year, concerned with the effects of changing land use on the ecology and climate of the Brazilian Amazon. It is primarily concerned with investigating the water, carbon and nutrient cycles, and brings together about 80 scientists from a number of Brasilian institutes, but especially from INPA in Manaus, CENA/USP in Pirac, icaba and EMBRAPA/CPATU in Belem.Major activities include the better identification of water vapour producing precipitation, to establish better water vapour circulation models (via 180, deuterium and 3H analysis, plus radiosonding); the study of water relations of isolated forest areas; the study of various phases of the carbon cycle especially soil organic matter; primary production; and nitrogen and soil fertility studies.A first phase Regional Amazon Model (RAM) for hydrology is being developed, and it should shortly be possible to make a first research-based attempt at modelling the carbon cycle of the Amazon region.This coordinated project represents in most ways the type of research required for the International Geosphere-Biosphere Programme (IGBP) and is a major Brasilian initiative.

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Section: Hydrological Cyclesupporting

confidence: 71%

Amazon bio-geosciences: Towards a synthesis through ?Amazonia I?

Vose

1989

GeoJournal

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“…These patterns match changes in the start of the dry season, as defined as the first month where potential evapotranspiration (PET) exceeds precipitation. For the Manaus area, average daily PET has been estimated at 3.5 mm/day or 105 mm/month (Marques et al 1980). Based on rainfall records from Manaus, this places the start of the 1993 dry season in May and the start in 1994 in July (Fig.…”

Section: Physical Attributes and Phenologymentioning

confidence: 99%

Spectral changes with leaf aging in Amazon caatinga

Roberts

Nelson

Adams

et al. 1998

Trees

135

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Significant gaps exist in the knowledge of tropical leaf spectra and the manner in which spectra change as leaves age in their natural environment. Leaf aging effects may be particularly important in tropical vegetation growing on nutrient poor soils, such as Amazon caatinga, a white sand community common in the Amazon Basin. Spectral changes observed in six caatinga dominants include decreased reflectance and transmittance and increased absorptance for epiphyll-coated older leaves. Near-infrared (NIR) changes were most significant. More detailed spectral and physical changes were studied in one dominant, Aldina heterophylla. Over 16 months, Aldina study plants produced one or two leaf flushes. During leaf expansion, leaf water content and Specific Leaf Area decreased rapidly. Over the first 6 months spectral changes occurred across the spectrum, resulting in decreased transmittance and increased absorptance in the visible and NIR and decreased visible and increased NIR reflectance. In contrast, significant spectral changes were restricted to the NIR over the last 9 months, which showed a 10% absorptance increase associated primarily with increasing epiphylls and necrosis. At the canopy scale, increased NIR absorptance provides a mechanism for producing seasonally varying forest albedo and changing NIR to red ratios, independent of changes in other canopy attributes. In the Amazon caatinga studied, all canopy dominants were subject to epiphyllic growth providing a mechanism for distinguishing these forest types spectrally from more diverse terrafirme forest or forest types with more rapid leaf turnover, such as second growth. These changes are observable using remote sensing and could be used to map caatinga and monitor interannual or seasonal variability in phenology. If these results can be extended to other communities with long-lived foliage, they may offer a means for mapping vegetation on the basis of leaf longevity.& k w d : Key words Leaf age · Aldina heterophylla · Amazon · Remote sensing · Caatinga& b d y :

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“…Therefore, 3 months can be taken as a first-order estimate of the residence time for the water in the Amazon hydrological system (Marques et al, 1980a). Comparison of the seasonal cycle of the basinwide, vertically integrated atmospheric moisture divergence and the Amazon streamflow at Obidos (500 km from the mouth), show that the latter lags the former by approximately 3 months.…”

Section: Aerological Datamentioning

confidence: 99%

Possible climatic impacts of tropical deforestation

Salati¹,

Nobre

1991

Climatic Change

Self Cite

107

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Large-scale conversion of tropical forests into pastures or annual crops will likely lead to changes in the local microclimate of those regions. Larger diurnal fluctuations of surface temperature and humidity deficit, increased surface runoff during rainy periods and decreased runoff during the dry season, and decreased soil moistrue are to be expected.It is likely that evapotranspiration will be reduced because of less available radiative energy at the canopy level since grass presents a higher albedo than forests, also because of the reduced availability of soil moisture at the rooting zone primarily during the dry season. Recent results from general circulation model (GCM) simulations of Amazonian deforestation seem to suggest that the equilibrium climate for a grassy vegetation in Amazonia would be one in which regional precipitation would be significantly reduced.Global climate changes probably will occur if there is a marked change in rainfall patterns in tropical forest regions as a result of deforestation. Besides that, biomass burning of tropical forests is likely adding CO 2 into the atmosphere, thus contributing to the enhanced greenhouse warming.

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Cálculo da evapotranspiração real na Bacia Amazônica através do método aerológico

Cited by 27 publications

References 2 publications

Amazon bio-geosciences: Towards a synthesis through ?Amazonia I?

Amazon bio-geosciences: Towards a synthesis through ?Amazonia I?

Spectral changes with leaf aging in Amazon caatinga

Possible climatic impacts of tropical deforestation

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