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

Abstract

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 ( = H/ ) of 3-5, while Le was higher than H during the wet season, resulting in a ≈ 1. 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.

Seasonal dynamics of surface energy fluxes over a center-pivot irrigated cropland in Saudi Arabia

“…Hence, the seasonal dynamics of ET and energy fluxes over agriculture fields is essential for the efficient agricultural water management (Santanello et al, 2013;Irmak et al, 2014). However, energy fluxes and ET varies across the crop growth period as the vegetative cover has potential to change energy partitioning due to its effect on the seasonal pattern and magnitude of radiation balance and albedo (Rodrigues et al, 2013).…”

“…In addition, longer duration of dry season (fallow state of a field) causes more dryness which affects the boundary-layer condition and destabilizes moisture regimes, VPD and surface water availability (Wizemann et al, 2015). Moreover, the change in land cover (cropped area to fallow area) affects the pattern of radiation fluxes of agricultural fields (Evrendilek et al, 2008;Rodrigues et al, 2013). The effect of climatic events (seasonal/annual and interannual variations) triggers the variation in energy fluxes across the crop growth stages.…”

Hourly interaction between wind speed and energy fluxes in Brazilian Wetlands - Mato Grosso - Brazil

“…The state of Mato Grosso contains three of main biomes of South America: the Amazon rainforest, the Cerrado (or savanna) and the Pantanal wetland (Rodrigues et al 2013(Rodrigues et al , 2014 The last two biomes have gained attention from researchers studying phenomena which promote balance between human and environmental activities. Because of the flow dynamics of matter and energy in these biomes, the cerrado and Pantanal are highly relevant for gaining a deeper understanding of environmental processes that govern the biosphere-atmosphere interactions across ecosystems (Curado et al 2016, Rodrigues et al 2016).…”

“…The quantification of latent heat (LE) and sensible heat (H) by the Bowen ratio method have been widely used in the last decade, mainly for determining the energy balance for studies on energy dynamics of forest and management availability of water for certain crops by ET (Alves and Pereira 2000, Hayashi et al 2002, Chen et al 2009, Giambelluca et al 2009, Rodrigues et al 2013). …”

“…LE and H are important parameters that directly drive variations in climate and can, in turn, alter the environmental variables driving mass and energy exchanges between the ground and the atmosphere (Falge et al 2005, Rodrigues et al 2013). Thus, LE and H fluxes are important variables in meteorological, hydrological and ecological analyses.…”