Evolution spatiotemporal of the albedo and surface vegetation cover in the watershed of the upper course of Paraíba river

Abstract

This study aimed to analyze the spatial and temporal variation of surface albedo and vegetation in the river basin of the upper course of the River Paraíba, as important indicators of the process of land degradation/desertification. The information of the two variables were obtained from 168 Modis (Moderate Resolution Imaging Spectro Radiometer), covering the period 2000-2013, for the months of each year of the series. The Mann-Kendall test (MK) was used to confirm the trend, for ? = 0.05 level of significance. The main results show that the average of the surface albedo values range between 11 and 21%, with peaks in February and minimum in July. The monthly average values of SAVI ranged from 0.18 to 0.36, with maximum in April and minimum in October. Rainfall is the variable that determines the variation in vegetation index and albedo in the region. The municipalities of São Sebastião do Umbuzeiro, Congo presented the lowest, and highest average valuesof albedo, respectively, due to climatic conditions and relief of the first city, with higher elevations, which provide more moisture. The municipality of Congo also had the lowest values of SAVI (0.15), showing an inverse correlation with the albedo values of the surface that results from the sparse or no vegetation.