author = "Dessay, Nadine and Laurent, Henrii and Machado, Luiz Augusto 
                         Toledo and Shimabukuro, Yosio Edemir and Batista, Getulio Teixeira 
                         and Diedhiou, Arona and Ronchail, Josyane",
          affiliation = "IRD Centre de Montpellier, ESPACE Unit, Montpellier, France and 
                         Laboratoire d'Etudes des Transferts en Hydrologie et Environnement 
                         (LTHE), Grenoble, France and ACA/IAE/CTA, Divisatiao Ciencias 
                         Atmosfericas, Instituto de Aeronautica e Espaco, Sao Jose dos 
                         Campos, SP 12228-904, Brazil and {} and Universidade de 
                         Taubat{\'e}, Depto. de Ci{\^e}ncias Agrarias, Taubat{\'e}, SP, 
                         Brazil and IRD Institut de Recherche pour le Developpement, Paris, 
                         France and Universite Paris Sorbonne - Paris IV, Paris, France",
                title = "Comparative study of the 1982-1983 and 1997-1998 El Nino events 
                         over different types of vegetation in South America",
              journal = "International Journal of Remote Sensing",
                 year = "2004",
               volume = "25",
               number = "20",
                pages = "4063--4077",
                month = "oct.",
             keywords = "South America, Climatology, Data reduction, Radiometers, Sensors, 
                         Data sets, Intercalibration, Normalized Difference Vegetation 
                         Index (NDVI).",
             abstract = "This work presents results which help to understand the behaviour 
                         of the Normalized Difference Vegetation Index (NDVI) anomalies 
                         over the South America continent during the two strongest El Nino 
                         events of the last century (1982-1983 and 1997-1998). The data 
                         used are parts of a long-term series (July 1981 to December 1999) 
                         of calibrated NDVI data derived from National Oceanic and 
                         Atmospheric Administration Advanced Very High Resolution 
                         Radiometer (NOAA AVHRR) datasets. Special emphasis has been given 
                         to the analysis of the response of the major Brazilian vegetation 
                         types. This paper introduces an approach that enhances NDVI 
                         anomalies relative to the long-term climatology of the region. We 
                         find a negative NDVI anomaly for most of the region during the 
                         1982-1983 event, whereas for the 1997-1998 event positive NDVI 
                         anomalies were observed over most regions. Only the Nordeste 
                         region showed a similar vegetation response for both events. We 
                         identify three possible factors that may play a role in the 
                         different NDVI responses to the two El Nino events. Firstly, poor 
                         intercalibration of sensors may account for some, but not all of 
                         the differences. Secondly the response of the vegetation may 
                         depend upon the climate conditions prior to the El Nino events. 
                         Thirdly, the difference in the onset date and the duration of the 
                         mature phase of the two El Nino events, associated with very 
                         different Atlantic surface temperatures are shown to have 
                         dynamical consequences which may impact upon the vegetation.",
           copyholder = "SID/SCD",
                  doi = "10.1080/0143116031000101594",
                  url = "http://dx.doi.org/10.1080/0143116031000101594",
                 issn = "0143-1161",
             language = "en",
           targetfile = "IJRS_Nadine_final.pdf",
        urlaccessdate = "26 jan. 2021"