@InProceedings{GrimmZill:2006:LaInRo,
               author = "Grimm, Alice Marlene and Zilli, Marcia Terezinha",
          affiliation = "Universidade Federal do Paran{\'a}, Departamento de 
                         F{\'{\i}}sica and Caixa Postal 19044. 81531-990 Curitiba, PR, 
                         Brazil (Grimm and Zilli)",
                title = "Interannual variability of summer rainfall in South America: 
                         large-scale influences and the role of antecedent conditions in 
                         spring",
            booktitle = "Proceedings...",
                 year = "2006",
               editor = "Vera, Carolina and Nobre, Carlos",
                pages = "1097--1103",
         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 = "South American monsoon system, precipitation, modes of 
                         variability, sea surface temperature, land-suface processes.",
             abstract = "The importance of the summer monsoon season to the annual total 
                         precipitation over most of South America is well known. The 
                         variability of monsoon precipitation is of utmost importance for 
                         agriculture, reservoir management, and natural disaster 
                         preparedness. Two previous studies with reconstructed rainfall 
                         from satellite estimates and gauge-based monthly totals, have 
                         stressed the influence of ENSO on summer precipitation. It is 
                         represented by the first mode of variability in these studies. The 
                         second mode represents the interannual and interdecadal 
                         variability in Northeast Brazil, whereas the third mode is 
                         completely different in both studies. The first two modes of 
                         summer precipitation in those studies do not have strongest 
                         components in the monsoon core region in South America. Are the 
                         regions with monsoon-like regime not prone to undergo strong 
                         interannual variations or, in other words, are the processes 
                         leading to monsoon rainfall in South America not prone to undergo 
                         interannual variations? If yes, would these processes be directly 
                         affected by remote or large-scale influences or indirectly, 
                         through regional interactions that are stronger in the summer 
                         season? In this study we intend to cast some light on these 
                         questions. We pursue the following objectives: i) to determine the 
                         principal modes of interannual variability of summer monsoon 
                         rainfall on the basis of relatively long series of rain gauge 
                         data; ii) to establish connections between the conditions in the 
                         beginning of the monsoon season and its peak; iii) to verify 
                         connections with global SST. Precipitation data from more than 
                         9000 stations over most of South America are averaged in 2.5 X 2.5 
                         degree boxes. These data are mainly concentrated in the Southern 
                         Hemisphere (SH) part of South America, where summer rainfall 
                         mostly dominates the annual cycle. Mean precipitation series for 
                         spring (SON) and summer (DJF) are formed for each of those boxes 
                         in the period 1961-2000, and submitted to Principal Component 
                         Analysis. Rotated and non-rotated modes of variability are 
                         determined and their relationship with global sea surface 
                         temperature SST) is assessed. Furthermore, we analyze the 
                         relationship between spring and summer precipitation, in order to 
                         detect influence of antecedent soil moisture conditions in spring 
                         on the peak summer monsoon rainfall. While some modes of summer 
                         rainfall variability bear similarity to modes determined in 
                         previous studies, there are also significant differences. There is 
                         an inverse relationship between a pair of similar modes in spring 
                         and summer, which suggests that antecedent conditions in spring 
                         may influence precipitation in summer. This relationship is even 
                         stronger when shorter periods within these seasons are analyzed, 
                         such as November and January. The analysis of the relationship 
                         between the precipitation modes and global SST indicates that the 
                         remote large-scale influences on interannual precipitation 
                         variability are much stronger in spring than in summer, suggesting 
                         a possible role of regional forcing in summer associated with 
                         surface-atmosphere interaction..",
  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/2005/10.31.22.07",
                  url = "http://urlib.net/ibi/cptec.inpe.br/adm_conf/2005/10.31.22.07",
           targetfile = "1097-1104.pdf",
                 type = "Monsoon systems and continental rainfall",
        urlaccessdate = "02 maio 2024"
}