Condutância Do Dossel, Condutância Aerodinâmica E Fator De Desacoplamento Em Floresta De Vochysia Divergens Pohl (Vochysiaceae) No Pantanal Brasileiro

Abstract

Neste trabalho avaliaram-se os mecanismos de controle da evapotranspiração por meio da condutância do dossel, condutância aerodinâmica e fator de desacoplamento em floresta de Vochysia divergens Pohl (Vochysiaceae) localizada no Mato Grosso no Pantanal Brasileiro. Durante o ano 2007 foram estimadas as variáveis: evapotranspiração, condutância do dossel, condutância aerodinâmica e pressão de vapor d'água. O fator de desacoplamento foi 0,58 e 0,51 durante as estações úmida e seca, respectivamente, indicando que o controle exercido pelo saldo de radiação sobre a evapotranspiração é predominante. O desacoplamento entre a cobertura vegetal e a atmosfera durante a estação úmida foi semelhante a estudos em florestas tropicais. Estes resultados acrescentam uma dimensão importante para a compreensão das características desta floresta inundável reconhecida internacionalmente.

Estimation of evapotranspiration and single and dual crop coefficients of acai palm in the Eastern Amazon (Brazil) using the Bowen ratio system

“…where u is wind speed (s m −1 ) at measurement height z (m), d is zero plane displacement (m), z 0 is surface roughness (m), and Ф m corresponds to the profile correction factor of the wind, according to Fraga et al (2015).…”

“…The inverted Penman-Monteith equation was used to determine g s , which indicates a biological control of evapotranspiration, according to the methodology described by Fraga et al (2015).…”

Biophysical controls of evapotranspiration in cowpea cultivation under different water regimes

“…Atmospheric demand and characteristics of the vegetated surface aerodynamically and physiologically regulate evapotranspiration through canopy roughness and stomatal activity (Silva et al, 2012;Fraga et al, 2015). Aerodynamic conductance is related to the turbulent atmospheric processes and is the parameter that represents the conductivity of this turbulent activity in the air layer close to the surface.…”

“…Based on the association of these aerodynamic and stomatal conductances of Penman-Monteith equation (Allen et al, 1998), McNaughton & Jarvis (1983) developed the concept of decoupling factor (Ω), an indicator of the interaction between the surface and the atmosphere, which allows establishing whether evapotranspiration is mainly controlled by either the vapor pressure deficit and stomatal conductance or the radiation balance (Silva et al, 2012;Fraga et al, 2015). Therefore, the objective was to analyze the variations of the decoupling factor and aerodynamic and stomatal conductances for cowpea subjected to different levels of water availability and during the reproductive phenological stages of the crop in the northeastern region of Pará state, Brazil.…”