Patterns of water and heat flux across a biome gradient from tropical forest to savanna in brazil

Humberto R. Da Rocha, Antonio O. Manzi, Osvaldo M. Cabral, Scott D. Miller, Michael L. Goulden, Scott Saleska, Natalia R. Coupe, Steven C. Wofsy, Laura S. Borma, R. Artaxo, George Vourlitis, José S. Nogueira, Fernando L. Cardoso, Antonio D. Nobre, Bart Kruijt, Helber C. Freitas, Celso Von Randow, Renata G. Aguiar, Jair F. Maia

Research output: Contribution to journalArticle

146 Citations (Scopus)

Abstract

We investigated the seasonal patterns of water vapor and sensible heat flux along a tropical biome gradient from forest to savanna. We analyzed data from a network of flux towers in Brazil that were operated within the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA). These tower sites included tropical humid and semideciduous forest, transitional forest, floodplain (with physiognomies of cerrado), and cerrado sensu stricto. The mean annual sensible heat flux at all sites ranged from 20 to 38 Wm-2, and was generally reduced in the wet season and increased in the late dry season, coincident with seasonal variations of net radiation and soil moisture. The sites were easily divisible into two functional groups based on the seasonality of evaporation: tropical forest and savanna. At sites with an annual precipitation above 1900 mm and a dry season length less than 4 months (Manaus, Santarém and Rondonia), evaporation rates increased in the dry season, coincident with increased radiation. Evaporation rates were as high as 4.0 mm d-1 in these evergreen or semidecidous forests. In contrast, ecosystems with precipitation less than 1700 mm and a longer dry season (Mato Grosso, Tocantins and São Paulo) showed clear evidence of reduced evaporation in the dry season. Evaporation rates were as low as 2.5 mm d-1 in the transitional forests and 1 mm d-1 in the cerrado. The controls on evapotranspiration seasonality changed along the biome gradient, with evaporative demand (especially net radiation) playing a more important role in the wetter forests, and soil moisture playing a more important role in the drier savannah sites.

Original languageEnglish (US)
Article numberG00B12
JournalJournal of Geophysical Research: Space Physics
Volume114
Issue number1
DOIs
StatePublished - Mar 28 2009

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Brazil
biome
savanna
tropical forests
tropical forest
savannas
heat flux
Heat flux
dry season
Evaporation
evaporation
cerrado
heat
gradients
evaporation rate
Water
ecosystems
water
Soil moisture
net radiation

ASJC Scopus subject areas

  • Soil Science
  • Forestry
  • Water Science and Technology
  • Palaeontology
  • Atmospheric Science
  • Aquatic Science
  • Ecology

Cite this

Patterns of water and heat flux across a biome gradient from tropical forest to savanna in brazil. / Da Rocha, Humberto R.; Manzi, Antonio O.; Cabral, Osvaldo M.; Miller, Scott D.; Goulden, Michael L.; Saleska, Scott; Coupe, Natalia R.; Wofsy, Steven C.; Borma, Laura S.; Artaxo, R.; Vourlitis, George; Nogueira, José S.; Cardoso, Fernando L.; Nobre, Antonio D.; Kruijt, Bart; Freitas, Helber C.; Von Randow, Celso; Aguiar, Renata G.; Maia, Jair F.

In: Journal of Geophysical Research: Space Physics, Vol. 114, No. 1, G00B12, 28.03.2009.

Research output: Contribution to journalArticle

Da Rocha, HR, Manzi, AO, Cabral, OM, Miller, SD, Goulden, ML, Saleska, S, Coupe, NR, Wofsy, SC, Borma, LS, Artaxo, R, Vourlitis, G, Nogueira, JS, Cardoso, FL, Nobre, AD, Kruijt, B, Freitas, HC, Von Randow, C, Aguiar, RG & Maia, JF 2009, 'Patterns of water and heat flux across a biome gradient from tropical forest to savanna in brazil', Journal of Geophysical Research: Space Physics, vol. 114, no. 1, G00B12. https://doi.org/10.1029/2007JG000640
Da Rocha, Humberto R. ; Manzi, Antonio O. ; Cabral, Osvaldo M. ; Miller, Scott D. ; Goulden, Michael L. ; Saleska, Scott ; Coupe, Natalia R. ; Wofsy, Steven C. ; Borma, Laura S. ; Artaxo, R. ; Vourlitis, George ; Nogueira, José S. ; Cardoso, Fernando L. ; Nobre, Antonio D. ; Kruijt, Bart ; Freitas, Helber C. ; Von Randow, Celso ; Aguiar, Renata G. ; Maia, Jair F. / Patterns of water and heat flux across a biome gradient from tropical forest to savanna in brazil. In: Journal of Geophysical Research: Space Physics. 2009 ; Vol. 114, No. 1.
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