Seasonal variations in the evapotranspiration of a transitional tropical forest of Mato Grosso, Brazil

The seasonal pattern of evapotranspiration (expressed as latent heat flux Qe) for a 28‐ to 30‐m‐tall tropical transitional (ecotonal) forest was quantified over an annual cycle using eddy covariance measurement and micrometeorological estimation techniques. The study was conducted near the city of S...

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Bibliographic Details
Published in:	Water resources research Vol. 38; no. 6; pp. 30-1 - 30-11
Main Authors:	Vourlitis, George L., Filho, Nicolau Priante, Hayashi, Mauro M. S., de S. Nogueira, José, Caseiro, Fernando T., Campelo Jr, José Holanda
Format:	Journal Article
Language:	English
Published:	American Geophysical Union 01-06-2002 Blackwell Publishing Ltd
Subjects:	Brazil, Mato Grosso, Sinop Canopy conductance decoupling factor energy balance Evapotranspiration Hydrologic budget Hydrology Meteorology and Atmospheric Dynamics micrometeorology Plant ecology Priestley-Taylor alpha Tropical meteorology Water/energy interactions Brazil Brazil, Mato Grosso
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Summary:	The seasonal pattern of evapotranspiration (expressed as latent heat flux Qe) for a 28‐ to 30‐m‐tall tropical transitional (ecotonal) forest was quantified over an annual cycle using eddy covariance measurement and micrometeorological estimation techniques. The study was conducted near the city of Sinop, in northern Mato Grosso, Brazil, which is located within the ecotone of tropical rain forest and savanna (cerrado). Although the majority of net radiation (Q*) was consumed by Qe (50–90%), seasonal variations in Qe were large and positively correlated with precipitation. Total daily Qe for the dry season (June–September) was on average 6.0 MJ m−2 d−1, while daily Qe for the transition (October–November and April–May) and wet (December–March) season periods were 7.5 and 10.0 MJ m−2 d−1, respectively. The seasonal variation in midday (0900–1500 LT) surface conductance (gs) was also positively correlated with precipitation. Analysis of the “decoupling factor” (Ω) indicated that the forest was strongly coupled to the atmosphere (Ω = 0.1–0.3) over the dry season and transition periods, suggesting that Qe was under relatively strong stomatal control. Although rainfall during the study period was above the long‐term (30‐year) average, our results indicate that the seasonal dynamics of Qe for the tropical transitional forest were more comparable to tropical savanna than to rain forest.
Bibliography:	ark:/67375/WNG-3BQZWZF3-R ArticleID:2000WR000122 istex:AD71470B260551EDD54235EC48E61F957F46127D ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0043-1397 1944-7973
DOI:	10.1029/2000WR000122