Leone Francisco Amorim Curado

Temporal Patterns of Energy Balance for a Brazilian Tropical Savanna under Contrasting Seasonal Conditions

The savanna of Central Brazil (locally known as cerrado) has a long history of land cover change due to human activity. These changes have led to the degradation of cerrado forests and woodlands, leading to the expansion of grass-dominated cerrados and pastures. Thus, the aim of this study was to evaluate the temporal variation in energy flux in areas of degraded, grass-dominated cerrado (locally known as campo sujo) in Central Brazil. The amount of partitioned into H declined as monthly rainfall increased and reached a level of approximately 30% during the wet season, while the amount of partitioned into increased as monthly rainfall increased and reached a level of approximately 60% during the wet season. As a result, H was significantly higher than during the dry season, resulting in a Bowen ratio (β = H/) of 3-5, while Le was higher than H during the wet season, resulting in a . These data indicate that the energy partitioning of grass-dominated cerrado is relatively more sensitive to water availability than cerrado woodlands and forests, and have important implications for local and regional energy balance.

Modeling the reflection of Photosynthetically active radiation in a monodominant floodable forest in the Pantanal of Mato Grosso State using multivariate statistics and neural networks.

The study of radiation entrance and exit dynamics and energy consumption in a system is important for understanding the environmental processes that rule the biosphere-atmosphere interactions of all ecosystems. This study provides an analysis of the interaction of energy in the form of photosynthetically active radiation (PAR) in the Pantanal, a Brazilian wetland forest, by studying the variation of PAR reflectance and its interaction with local rainfall. The study site is located in Private Reserve of Natural Heritage, Mato Grosso State, Brazil, where the vegetation is a monodominant forest of Vochysia divergens Phol. The results showed a high correlation between the reflection of visible radiation and rainfall; however, the behavior was not the same at the three heights studied. An analysis of the hourly variation of the reflected waves also showed the seasonality of these phenomena in relation to the dry and rainy seasons. A predictive model for PAR was developed with a neural network that has a hidden layer, and it showed a determination coefficient of 0.938. This model showed that the Julian day and time of measurements had an inverse association with the wind profile and a direct association with the relative humidity profile.

Geothermal Dynamics in Vochysia Divergens Forest in a Brazilian Wetland

Research involving the thermal soil dynamics of wetland areas has not yet been explored in a way that promotes a deeper understanding of the dynamics of this region. This makes it necessary for further studies to contribute to the understanding of this biome. In the present work, we studied the thermal dynamics of the soil contrasting seasonal conditions in the Vochysia Divergens Forest. The Fourier equation was used to analyze the influence of the thermal conductivity and thermal gradient on the soil heat flux. We determined how variable water content causes the system to behave differently in the four seasons, observing seasonality in soil when completely dry and when completely flooded.

CONDUTÂNCIA DO DOSSEL, CONDUTÂNCIA AERODINÂMICA E FATOR DE DESACOPLAMENTO EM FLORESTA DE VOCHYSIA DIVERGENS POHL (VOCHYSIACEAE) NO PANTANAL BRASILEIRO

In this study the control mechanisms of evapotranspiration through canopy conductance, aerodynamic conductance and decoupling coefficient for aVochysia divergens Pohl (Vochysiaceae) forest located in the State of Mato Grosso in the Brazilian Pantanal are assessed. Over the course of the 2007 year, estimates of the following biophysical variables were made: evapotranspiration, canopy conductance, aerodynamic conductance and vapor pressure deficit. The decoupling coefficient was 0.58 and 0.51 for wet and dry season, respectively, indicating that the control offered by the net radiation on the evapotranspiration is predominant. The decoupling between the vegetation cover and atmosphere during the wet season was similar to studies in tropical forests. These results add an important dimension to our understanding on the characteristics of this internationally important wetland.

ESTIMATION OF THE VOLUME AND TURGOR PRESSURE STOMATAL OF VICIA FABA ALONG DAY

The stomata control the plant water outlet and this control depends on the stomatic volume variation which in turn depends on the variation of the stomatic turgor pressure. Therefore, the aim of this study was to estimate the volume and turgor pressure of the stomata Vicia faba through the day. The biophysical parameters of the stomata Vicia faba found in the literature and Van’t Hoff equation were utilized to estimate the osmotic pressure generated by the osmotically active solutes (potassium, chloro and sucrose). The resulting values are in agreement with literature and can be used in simulations, such as the study of leaf transpiration through the equation Weyers and Meidner (1990).

Analysis of thermal conductivity in a seasonal flooded forest in the northern Pantanal

Research involving the flux of energy in the soil has been intensified in order to increase the understanding of the geophysical behavior of the Pantanal-Brazil. In present study was examined the seasonal variation of the thermal soil conductivity in the Pantanal for the study of energy flow in the soil to Pantanal region. The average values obtained by the Fourier equation showed that the soil thermal conductivity in the wet and dry seasons was 8.69 W.m-1.oC-1 and 6.65 W.m-1.oC-1 respectively. The seasonal variation of the thermal conductivity of the soil was 30.68% higher in the wet season than in the dry season due to soil moisture in the wet season. It was also noted that the seasonal variation of temperature in the soil layer was higher in the wet season than in the dry season due to a lower incidence of solar radiation in this season.

ESTIMATIVA SAZONAL DA EMISSIVIDADE ATMOSFÉRICA ATRAVÉS DA EQUAÇÃO DE BRUTSAERT NO NORTE DO PANTANAL MATO-GROSSENSE

Nos ultimos anos, tem-se intensificado as pesquisas ambientais na regiao do Pantanal a fim de se conhecer o comportamento micrometeorologico da regiao. No presente trabalho buscou-se verificar se a equacao de Brutsaert pode ser utilizada para a estimativa da emissividade atmosferica na regiao do pantanal Mato-grossense, considerando dois periodos sazonais, sendo um chuvoso e um seco, tendo como base para comparacao os dados obtidos na estacao micrometeorologica aplicados na equacao do balanco de energia, a fim de que possa contribuir para as pesquisas destinadas ao estudo das trocas de energia entre a superficie e a atmosfera da regiao pantaneira. Os resultados obtidos mostraram-se consistentes para o metodo utilizado, pois os valores estimados pela equacao de Brutsaert aproximaram-se significativamente dos valores obtidos atraves da equacao do balanco de energia que utilizou dados coletados no local para os dois periodos estudados. Palavras–chave: Equacao de Brutsaert, periodos sazonais, balanco de energia, Pantanal