AVALIAÇÃO DE UM CONJUNTO DE ÍNDICES NA IDENTIFICAÇÃO DO RISCO DE OCORRÊNCIA DE DESERTIFICAÇÃO NA SUB-BACIA TAPEROÁ-PB

Evaluation of a set of indices in the identification of risk to desertification in the Taperoá Sub-basin, PB

Abstract

This is study is of the Risk of Tendency to Desertification Index (RTDI). It comprises a group of soil and vegetation spectral indexes, climate indexes and human impact to identify the degree of desertification of a semiarid region of Brazil. This study the goal is to examine, validate and adapt the RTDI methodology in the considering a temporal analysis between the years of 1995 and 2015 taking into account the seasonality. The RTDI was also tested according to the class distribution range, using equal and quartile intervals, considering the variation of the SAVI L parameter (0.8, 0.9 and 1). In addition to that, the results of the collected field data were validated including the verification and categorization of the desertification degree according to experienced professionals. It was done comparative analysis pixel / point by performance indexes, identifying areas that are susceptible to desertification, according to the field survey and the estimates obtained the RTDI. The application of the RTDI with quartile interval class distribution, during the dry period and using the SAVI parameter L =1, presented better performance than the other method variations. The applied indexes ’driving force estimates showed that the parameters related to the soil and vegetation were decisive in terms of the classification level of the risk of tendency to desertification.