author = "Tomasella, Javier and Vieira, Rita M{\'a}rcia Silva Pinto and 
                         Barbosa, Alexandre Augusto and Rodriguez, Daniel A. and Santana, 
                         Marcos de Oliveira and Sestini, Marcelo F.",
          affiliation = "{Centro Nacional de Monitoramento e Alertas de Desastres Naturais 
                         (CEMADEN)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Alberto Luiz Coimbra de P{\'o}s-Gradua{\c{c}}{\~a}o 
                         e Pesquisa de Engenharia} and {Minist{\'e}rio do Meio Ambiente} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Desertification trends in the Northeast of Brazil over the period 
              journal = "International Journal of Applied Earth Observation and 
                 year = "2018",
               volume = "73",
                pages = "197--206",
                month = "Dec.",
             keywords = "NDVI, Desertification, Brazilian Northeast.",
             abstract = "Information about changes in land use and land cover is useful to 
                         address issues related to drylands management, as well as to 
                         support decision-making related to the sustainable use of soils. 
                         Since drylands are frequently affected by accelerated soil 
                         erosion, land degradation and desertification associated with 
                         vegetation cover losses, constant monitoring of land use and land 
                         cover changes are required. However, land use and land cover maps 
                         are often not available, making it difficult to monitor 
                         degradation. Therefore, in this work, we developed an efficient 
                         mapping method to monitor bare soil areas, which are indicative of 
                         land degradation in the case of the Northeast of Brazil, using 
                         Normalized Difference Vegetation Index images. The proposed 
                         methodology was field calibrated and applied to the region using 
                         17-year (20002016) NDVI maps, with a spatial resolution of 250 m. 
                         Based on bare soil mapping, we estimated the degree of degradation 
                         using an index calculated from the persistence and frequency of 
                         bare soil during the study period. The results indicated that the 
                         degraded areas increased in the period of the study, mainly in 
                         areas of pasture and Caatinga. This expansion has been accelerated 
                         due to the severe drought that affected the region since 2011.",
                  doi = "10.1016/j.jag.2018.06.012",
                  url = "http://dx.doi.org/10.1016/j.jag.2018.06.012",
                 issn = "0303-2434",
             language = "en",
           targetfile = "tomasella_desertification.pdf",
        urlaccessdate = "19 jan. 2021"