@InProceedings{GrimmFlacTede:2010:ENExRa,
               author = "Grimm, A M and Flach, R A and Tedeschi, Renata Gon{\c{c}}alves",
          affiliation = "Physics, Universidade Federal do Paran{\'a}, Curitiba, Brazil and 
                         Physics, Universidade Federal do Paran{\'a}, Curitiba, Brazil and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "ENSO and extreme rainfall events in present and future climate in 
                         South America",
            booktitle = "Abstracts...",
                 year = "2010",
         organization = "The Meeting of the Americas.",
             keywords = "Extreme events, climate change and variability, precipitation, 
                         ENSO.",
             abstract = "Analysis with observed data shows a clear association between ENSO 
                         (El Niņo / La Niņa) episodes and the frequency of extreme rainfall 
                         events over South America. ENSO is the main source of interannual 
                         variability in South America, and its influence varies throughout 
                         the annual cycle. For instance, in austral spring (November) it is 
                         very significant in southeastern South America, producing increase 
                         (decrease) of extreme events in the La Plata Basin during El Niņo 
                         (EN) (La Niņa, LN) episodes. In peak summer monsoon season 
                         (January), the extreme events in Central-East South America, in 
                         the South Atlantic Convergence Zone and in the core monsoon region 
                         are enhanced (hampered) during EN (LN) episodes. In austral autumn 
                         (April), there is significant enhancement of extreme events in the 
                         La Plata Basin during EN episodes, while at the same time of LN 
                         episodes the frequency of extreme events is increased in Northeast 
                         Brazil. These significant changes in extremes are much more 
                         extensive than the corresponding changes in monthly rainfall, 
                         because the highest sensitivity to ENSO is in the extreme range of 
                         daily precipitation. The ENSO-related changes in the frequency of 
                         extreme rainfall are important, since the most dramatic 
                         consequences of climate variability result from changes in extreme 
                         events. Therefore, an important issue is the assessment of the 
                         impact of global anthropogenic climate change on ENSO and its 
                         impact on extreme rainfall in South America. Possible future 
                         changes in the influence of ENSO on the frequency of extreme 
                         precipitation events in South America are analyzed through the 
                         outputs of the coupled model ECHAM5-OM for the twentieth century 
                         climate (1960-2000), and the future climate scenario SRES-A2 
                         (2060-2100). Extreme events are defined as three-day mean 
                         precipitation above the 90th percentile. The EN and LN years in 
                         the model output are determined from the Niņo 3 SST anomalies (as 
                         in the observations), and verified against the extreme phases of 
                         the ENSO mode of SST variability, for both periods. The model 
                         reproduces well the strongest observed impacts of ENSO in the 
                         present climate, although not all their features. The areas with 
                         consistent impact on the frequency of extreme events are generally 
                         extended in the future climate, and the ENSO-related frequency is 
                         enhanced with respect to the present in several instances, such as 
                         the spring in southeastern South America (La Plata Basin). Also 
                         the shifts produced in the daily rainfall distributions, with 
                         respect to present climate during EN, LN and all years are 
                         examined. In southern Brazil, for instance, the probability of 
                         light rainfall in spring is reduced, while it increases in the 
                         heavy rainfall tail of the frequency distributions.",
  conference-location = "Foz do Igua{\c{c}}u, BR",
      conference-year = "08-12 aug 2010",
             language = "en",
        urlaccessdate = "2024, May 18"
}