Precipitable water and water vapor flux between Belém and Manaus()

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

doi:10.1590/1809-43921977073355

Cited by 51 publications

(25 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Molion (1976) and Lettau et al (1979), by means of climatonomic analysis, have concluded that 50% of the present precipitation in the Amazonian rainforest comes from water recycled by the vegetation itself and the other 50% from the Atlantic ocean. This fact was further corroborated by other methodologies (Marques, 1976;Marques et al, 1977;Salati, 1987). Later, Nobre et al (1988) concluded that 58% of rainfall came from local evapotranspiration.…”

Section: Uncertainties In Simulation Models For South Americasupporting

confidence: 77%

Climate change predictions for South America

1991

View full text Add to dashboard Cite

Some of the characteristics of predicted climate changes for South America are analysed for the years 2010 and 2050. These predictions are based on the results of three-dimensional Global Circulation Models (GCMs). The results differ between models (GISS, NCAR-CCMs and GFDL), particularly when applied to regional and sub-regional scales and to time scales of less than one-year intervals. It is concluded that these differences are due to the particular structure of each model as well as to the lack of sufficient basic data from the South American sub-continent. The dynamics of vegetation cover play an important role in future water balance changes. The changes in surface temperatures predicted by the GISS model are discussed in relation to changes in the climaticdynamic base stemming from anthropogenic changes in the vegetation cover.

show abstract

Section: Uncertainties In Simulation Models For South Americasupporting

confidence: 77%

Climate change predictions for South America

1991

View full text Add to dashboard Cite

show abstract

“…For example, Russell and Miller (1990) shows a high evapotranspiration ratio, since the parameterization of evapotranspiration or that of groundwater storage is not adequate. In Russell and Miller (1990), the evapotranspiration from tropical forests was estimated by the bulk formula and was also overestimated, being almost as same as the annual potential evapotranspiration calculated by the Thornthwaite method (Marques et al, 1977). The GCM's spatial resolution (4**5*) might be one of the reasons for the overestimation of evapotranspiration.…”

Section: Comparison With Previous Studiesmentioning

confidence: 86%

“…In addition to the estimation of the annual evapotranspiration using the water balance method of the basin, Villa nova et al (1976) and Marques et al (1977) calculated the annual potential evapotranspiration from fairly wide area, if not the entire basin. In these studies, the annual evapotranspiration estimated by the water balance method was smaller than the annual potential evapotranspiration and their results are in contraciction with those of the small experimental area near Manaus.…”

Section: Comparison With Previous Studiesmentioning

confidence: 99%

The Water Budget in the Amazon River Basin during the FGGE Period

Matsuyama

1992

Journal of the Meteorological Society of Japan

View full text Add to dashboard Cite

The seasonal change of the water budget in the Amazon river basin during the FGGE period is investigated, using the global objective analyzed data set, precipitation data and river discharge data. Substituting these data into the atmospheric water balance equation and that of the basin, the evapotranspiration and relative value of basin storage are estimated and the relationships of water balance terms are examined.The annual water vapor flux convergence, calculated using the FGGE "main" III-b data set analyzed at the European Centre for Medium-Range Weather Forecasts, is estimated to be smaller than the annual runoff obtained by river discharge data. This is due to the characteristics of this global objective analyzed data set that it is made by the 4-dimensional data assimilation method which expresses the divergence and convergence of wind in the tropics as weaker than in the real state. The seasonal change pattern of precipitation shows good correspondence to that of water vapor flux convergence, which is multiplied by the factor 1.37 in order that its annual value meets the annual runoff. Evapotranspiration, estimated by the atmospheric water balance equation, remains almost constant within a year and the seasonal change of basin storage is very large. This result indicates that evapotranspiration in the entire Amazon river basin is not affected by the seasonal change of basin storage even in the dry season.The evapotranspiration ratio (evapotranspiration/precipitation) of the dry season is larger than that of the rainy season. It is concluded that the role of evapotranspiration on the water cycle in the Amazon river basin is relatively more important in the dry season than in the rainy season.

show abstract

“…Disturbance of the vegetation cover not only changes the surface albedo, but also can affect the surface-atmosphere energy exchange, by altering the relative proportions of sensible to latent heat (the Bowen ratio), largely through changes in evapotranspiration. Up to 50% of the rainfall on Amazonian tropical forests may be recycled through evapotranspiration (Marques et al, 1977;Salati and Vose, 1984). Thus large-scale forest clearance could significantly affect evapotranspiration and precipitation.…”

Section: Climatic Implications Of Anthropogenic Vegetation Modificationmentioning

confidence: 99%

A survey of anthropogenic vegetation changes in West Africa during the last century ? climatic implications

Gornitz

1985

Climatic Change

View full text Add to dashboard Cite

The extent of albedo change resulting from anthropogenic modification of the vegetation cover over the last century has been investigated in West Africa. The climatic implications of these changes are briefly discussed.West Africa spans a suite of vegetation zones ranging latitudinally northward from tropical rainforest to desert scrub, and comprises environmental problems from extremely rapid deforestation of the tropical forests in Ivory Coast or Ghana to desertification in the Sahel.Historical vegetation changes have been digitized on a 1 ~ x 1 ~ grid map based on a literature survey of government censuses, forestry and agricultural reports, supplemented by atlases, and other historical, economic and geographic sources.The principal processes of land cover modification during the last century include clearing of the natural vegetation for agriculture, grazing, logging, and degradation of marginal semi-arid to arid ecosystems by excessive grazing or cultivation. Forestry surveys for West Africa suggest clearance of around 56% of the forest zone; estimated losses for Ivory Coast, Ghana, and Liberia range between 64% and 70%. Estimates of total land conversion range between 88 million ha, from the digitized land use map (Figure 4) to 122.8 million ha, from extrapolation of forestry data (Section 3.1).The change in albedo corresponding to the land use modification is relatively small, using conservative estimates for desertification amounting to an increase of around 0.4% regionally over 100 yr and 0.5% since agriculture began. Thus 4/5 of the total albedo may have occurred within the last century, Additional assumptions regarding desertification and a lower albedo value for tropical forest compensate for each other and do not significantly alter the result of the initial calculation. The maximum zones of increased albedo are concentrated in the forest zone (4 ~ -8 ~ N) and savanna-southern sahel (10 ~ 12 ~ ) which correspond to zones of maximum agricultural and population growth. Between 13 ~ N and 17 ~ N, the albedo change is small or negative due to both less intensive land utilization and replacement of scattered vegetation on exposed sandy soil by lower albedo irrigated crops.These estimates may represent a lower limit, particularly if desertification is more extensive than initially assumed. Under an extreme assumption that the entire Sahel zone between 14~ ~ N has been desertified, the regional mean albedo could increase by as much as 4%. This represents an upper limit to likely historical anthropogenic disturbances of the land surface.Although historical climate records show three major droughts during the 20th century (1910, 1940's, 1969, possibly continuing into the 1980Nicholson, 1980a;Hare, 1983), and stream flow fluctuations which correlate well with precipitation (Faure and Gac, 1981 ;Palutikof et al., 1981), these records do not appear to indicate a regional secular decrease in precipitation as suggested by several climate models. Evidence for apparent desiccation or 'desert creep' (= 'desertificati...

show abstract

Precipitable water and water vapor flux between Belém and Manaus()

Cited by 51 publications

References 0 publications

Climate change predictions for South America

Climate change predictions for South America

The Water Budget in the Amazon River Basin during the FGGE Period

A survey of anthropogenic vegetation changes in West Africa during the last century ? climatic implications

Contact Info

Product

Resources

About