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@InProceedings{PscheidtGrim:2006:InElNi,
               author = "Pscheidt, Ieda and Grimm, Alice Marlene",
          affiliation = "Universidade de S{\~a}o Paulo, Instituto Astron{\^o}mico, 
                         Geof{\'{\i}}sico e Ci{\^e}ncias Atmosf{\'e}ricas, Departamento 
                         de Ci{\^e}ncias Atmosf{\'e}ricas and Rua do Mat{\~a}o, 1226 - 
                         Cidade Universit{\'a}ria -05508-900- S{\~a}o Paulo - SP, Brasil 
                         (Pscheidt) and Universidade Federal do Paran{\'a}, Departamento 
                         de F{\'{\i}}sica, Centro Polit{\'e}cnico - Campus III - Jardim 
                         das Am{\'e}ricas - 81531-990 - Curitiba- PR, Brasil (Grimm)",
                title = "The influence of El Niņo and La Niņa episodes in the occurrence of 
                         extreme precipitation events over Southern Brazil",
            booktitle = "Proceedings...",
                 year = "2006",
               editor = "Vera, Carolina and Nobre, Carlos",
                pages = "365--370",
         organization = "International Conference on Southern Hemisphere Meteorology and 
                         Oceanography, 8. (ICSHMO).",
            publisher = "American Meteorological Society (AMS)",
              address = "45 Beacon Hill Road, Boston, MA, USA",
             keywords = "El-Niņo, extreme events, precipitation, regional analysis, 
                         variability.",
             abstract = "El Niņo (EN) and La Niņa (LN) episodes cause impacts in the 
                         precipitation over Southern Brazil. The impact on the frequency of 
                         extreme precipitation events is here regionally analysed. November 
                         is a period with increase of severe rain events in EN and 
                         reduction in LN. During July of the following year also occurs 
                         increase/reduction of extreme events in some areas. The 
                         precipitation and the number of extreme events in homogeneous 
                         areas with respect to significant increase or reduction of severe 
                         rain events show significant correlation with Sea Surface 
                         Temperature (SST) in some regions of the globe, mainly those 
                         affected by El Niņo-Southern Oscilation (ENSO) episodes. 
                         Notwithstanding, lower-frequency variability is also associated 
                         with the variation of these extremes. The variation of the number 
                         of severe rain events between different EN and LN episodes seems 
                         to be associated with the variation of SST in certain regions. The 
                         most recurrent patterns of atmospheric circulation favoring the 
                         occurrence of extreme events are present in extreme events during 
                         both El Niņo and La Niņa episodes, as well as during neutral 
                         years. However, composites of monthly anomalies in EN and LN 
                         years, show that the large-scale favorable conditions for the 
                         occurrence of extreme events appear more during EN than during LN 
                         episodes. This explains the large difference between the frequency 
                         of those events during EN and LN episodes. Composites of anomalies 
                         show differences between EN years with more severe rain events and 
                         EN years with less of these events with respect to neutral years, 
                         mainly in the fields of global SST, vorticity advection at 500 
                         hPa, geopotencial height at 850 hPa, streamfunction at sigma level 
                         0.21 and divergence of vertically integrated moisture flux. These 
                         fields show patterns favorable to precipitation during the years 
                         with increase in the number of extreme events and unfavorable in 
                         years with reduction of these events. During November of EN years 
                         with more severe events than normal there is advection of ciclonic 
                         vorticity over Southern Brazil and positive SST anomaly in the 
                         equatorial East Pacific much more intense than that observed in 
                         years with less extreme events. When there is a reduction of 
                         extreme precipitation events in July of the year following the 
                         onset of an EN episode there are positive anomalies of 
                         geopotencial height at low levels and negative at high levels, 
                         indicating anomalous subsidence. Furthermore, there are 
                         significant negative SST anomalies in the equatorial East Pacific, 
                         while in years with more severe events this does not occurr.",
  conference-location = "Foz do Igua{\c{c}}u",
      conference-year = "24-28 Apr. 2006",
             language = "en",
         organisation = "American Meteorological Society (AMS)",
                  ibi = "cptec.inpe.br/adm_conf/2005/10.24.16.24",
                  url = "http://urlib.net/rep/cptec.inpe.br/adm_conf/2005/10.24.16.24",
           targetfile = "365-370.pdf",
                 type = "Climate change in the SH",
        urlaccessdate = "27 jan. 2021"
}


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