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Universidade Federal do Rio Grande do Norte (UFRN) 2022

Análise do albedo em áreas de caatinga preservada e substituída por pastagem

Souza, Alcindo Mariano de

Titre : Análise do albedo em áreas de caatinga preservada e substituída por pastagem

Auteur : Souza, Alcindo Mariano de

Université de soutenance : Universidade Federal do Rio Grande do Norte (UFRN)

Grade : Doutorado em Ciências Climáticas 2022

Résumé partiel
The caatinga is one of the endemic biomes most vulnerable to climate change. Studies of the consequences of changes in biophysical factors, among them the surface albedo, are relevant to understand the role of this biome in the climate of the Northeast Region of Brazil. Understanding the processes that lead to albedo changes through analysis in caatinga areas can help in the preservation and more appropriate use of its resources. In this perspective, a comparative analysis between the albedo of a preserved caatinga area and another one anthropized in pasture with grazing management brings important information for the perception of possible consequences of land use and helps in the understanding of degradation and contributes to the preservation of the biome. Also important are information on the potential of using albedo in grasslands as a climate change mitigation strategy through Solar Radiation Management (SEM). Thus, the study was conducted from observations of the components of the net radiation at the surface in two environments : Seridó Ecological Station considered as preserved caatinga (Caatinga), located in the municipality of Serra Negra do Norte and ; Jundiaí Agricultural School considered caatinga replaced by pasture with management (Pasture), in Macaíba, both in the state of Rio Grande do Norte. The albedo data comprised an annual rainfall cycle within four periods : the dry season, the transition between dry and rainy, rainy, and the transition between rainy and dry in both Caatinga and Pasture. The albedo averages were higher in the Pasture in all seasons, with a value of 0.18 in the annual cycle, showing little seasonal variability. In the Caatinga, the albedo average was 0.15, with the rainy to dry transition season being the one with the highest value and equal to 0.16. The biggest difference in the average albedo between the Pasture and the Caatinga happened in the dry season and the smallest in the rainy season and in the transition between dry and rainy season. Although the precipitation in the period was higher in the pasture with 992.7 mm, it still had a higher average albedo compared to the Caatinga, which had a cumulative precipitation of 507.6 mm in the period. The average solar elevation was also higher in the Pasture, which would influence the reduction of the difference between the average albedo in relation to the Caatinga. However, the albedo based on the daily mean values was not significantly influenced by the solar elevation. Regarding the average albedo at each time of day, there was a strong negative correlation for all seasons in the Pasture, also showing a greater amplitude in the albedo variation throughout the day in relation to the Caatinga


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