@InProceedings{CavalcantiBarr:2022:SuPrEx,
               author = "Cavalcanti, Iracema Fonseca de Albuquerque and Barreto, Naurinete 
                         de Jesus da Costa",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Subseasonal Predictions of Extreme Precipitation over South 
                         America from S2S ECMWF Model",
                 year = "2022",
         organization = "AGU Fall Meeting",
            publisher = "AGU",
             abstract = "Wet and dry conditions in Southeast and South Brazil produce 
                         social and economic impacts, as these regions have large 
                         population, agriculture activities and hydroelectricity power 
                         generation. Seasonal predictions have been able to alert for the 
                         precipitation conditions in the South region, due to the influence 
                         of ENSO, which is well predicted by climate models. However, 
                         Southeast Brazil, located in a transition region between 
                         Northeast, which is also affected by ENSO, and South, is less 
                         predictable at the seasonal timescale. Predictions at subseasonal 
                         timescale have been studied following the Subseasonal to Seasonal 
                         (S2S) project, with the availability of hindcasts of several 
                         global models. In the present study, reforecasting data from S2S 
                         ECMWF model are used to analyze predictions of extreme 
                         precipitation (wet and dry cases) in Southeast and South Brazil 
                         identified with GPCP data. Weekly averages of observed 
                         precipitation anomalies were obtained for DJF from 1999 to 2010 
                         and the six more extreme wet and dry cases were selected to verify 
                         the predictions. The analyses were performed using an ensemble of 
                         four members of the ECMWF reforecasts for the weeks predicted two 
                         weeks in advance. Observations show that extreme precipitation in 
                         Southeast and South Brazil present a dipole characteristic, with 
                         opposite anomalies. Hindcasts produced by S2S ECMWF model 
                         indicated similar patterns of extremes, for wet and dry cases 
                         occurring in Southeast and South Brazil. Although the model 
                         patterns are similar to observations, the intensity and extension 
                         of precipitation anomalies are lower and smaller in the model. The 
                         timeseries of normalized precipitation anomalies indicate that the 
                         sign of anomalies predicted by the model was consistent with the 
                         observed sign, although the intensity was not the same in the 
                         majority of cases. The model was also able to represent the 
                         wavetrains over the Pacific and South America, associated with the 
                         anomalies, and features of Madden-Julian Oscillation, which can 
                         provide a complementary information to the subseasonal 
                         predictions.",
  conference-location = "Chicago, IL",
      conference-year = "12-16 Dec. 2022",
        urlaccessdate = "20 maio 2024"
}