Evaluation in the Detection of Environmental Changes in the High Ipanema Watershed

Abstract

The objective of this study was to identify and evaluate the different degrees of environmental susceptibility of the High Ipanema watershed, covering part of the municipalities of Arcoverde and Pesqueira in the state of Pernambuco, to climatic variability and degradation process. The data of monthly precipitation of the historical series (1962 to 2015) were used for the calculation of the rainfall anomaly index (IAC), considering the temporal means of the local precipitations, for the determination of dry and humid periods. The biophysical parameters were estimated for the detection of environmental changes in the watershed, applying components of the SEBAL algorithm using Landsat 5-TM and 8-OLI/TIRS images. The results presented a predominance of negative IACs for the interannual variability with more extreme inflection points in the rainy years, which shows the whole watershed with an anomaly index between dry and rainy. There is also strong evidence of the influence of the occurrence of El Niño and La Niña phenomena, together with or not on the positive and negative phases of the Atlantic Dipole, in the drought and rainfall events in the watershed. With the biophysical parameters analyzed it was found that the northwest part of the watershed presents a considerable area of exposed soils with a degree of susceptibility to degradation.

Keywords:
rainfall anomaly index; biophysical parameters; semiarid