author = "Vargas, Gabriel and Rutllant, Jos{\'e} and Ortlieb, Luc",
          affiliation = "Universidad de Chile, Facultad de Ciencias F{\'{\i}}sicas y 
                         Matem{\'a}ticas, Departamento de Geolog{\'{\i}}a, Plaza Ercilla 
                         803, Santiago, Chile (Vargas). and Universidad de Chile, Facultad 
                         de Ciencias F{\'{\i}}sicas y Matem{\'a}ticas, Departamento de 
                         Geof{\'{\i}}sica, Blanco Encalada 2002, Santiago, Chile 
                         (Rutllant). and Institut de Recherche pour le D{\'e}veloppement 
                         (IRD), PALEOTROPIQUE, 32 Avenue Henri Varagnat, F-93143, Bondy 
                         Cedex, France.",
                title = "Onset of modern ENSO teleconnections and climate mechanisms for 
                         Holocene debris flows along the hyperarid coast of Northern 
                         Chile-Southern Peru",
            booktitle = "Proceedings...",
                 year = "2006",
               editor = "Vera, Carolina and Nobre, Carlos",
                pages = "1629--1634",
         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 = "Coastal Atacama desert, El Niņo-Southern oscillation, Holocene 
                         debris flows.",
             abstract = "In its modern sense, El Niņo-Southern Oscillation (ENSO) 
                         encompasses tropical-extratropical climate teleconnections that 
                         result into positive rainfall anomalies in subtropical western 
                         South America. The hyper-arid coastal region of southern Peru and 
                         northern Chile, located at the core of the Atacama Desert, 
                         exhibits a transitional climate between this subtropical regime 
                         and the near-equatorial region where direct ENSO effects are 
                         experienced. Meteorological mechanisms associated to the 
                         occurrence of heavy rainfall episodes along the coastal areas of 
                         southern Peru and northern Chile have been assessed to investigate 
                         their relationship with modern tropical-extratropical climate 
                         teleconnections. In this context the onset and evolution of 
                         Holocene El Niņo manifestations are inferred from the analysis of 
                         new and previous geologic information in this hyper-arid coastal 
                         desert. Our results indicate that heavy rainfall and debris flow 
                         events in the southern Peru coastal region occur mostly, but not 
                         exclusively, associated to the build-up of potential instability 
                         due to positive sea-surface temperature anomalies, and its 
                         episodic release by lifting the marine boundary layer in 
                         connection with deep mid-latitude troughs and associated 
                         jet-streaks from equatorially-deflected Pacific South America 
                         (PSA) teleconnection patterns during the mature (austral summer) 
                         and the development phase (austral winter-spring) of El Niņo 
                         events, respectively. Along the coast of northern Chile, those 
                         events occur almost exclusively in austral winter-spring. The 
                         comparison of debris flow and flood deposits from both areas 
                         support the onset of modern El Niņo manifestations at 5,300-5,500 
                         Cal. BP, as well as increased frequency of major events during the 
                         last thousand of years and particularly during the 20th century, 
                         consistently with other proxies of ENSO variability from the 
                         western slope of the Andes and from the equatorial Pacific Ocean. 
                         Different manifestations during the late Pleistocene and early to 
                         mid Holocene in both regions suggest that this climate 
                         teleconnection pattern did not operate at that time. We suggest 
                         that an increased frequency of debris flows between 12,900 and 
                         8,400 Cal. BP exclusively in southern Peru, previously interpreted 
                         as an indication of strong El Niņo events at that time, is most 
                         probably associated to short but intense heavy rainfall episodes, 
                         similar to those that develop at present times during the late 
                         winter-spring season in non-El Niņo conditions, in which low-level 
                         wind convergence at the bend of the South American west coast 
                         (18°S) provides an extra lifting mechanism that amplifies side 
                         effects of mid-latitude disturbances. These condition would be 
                         enhanced in austral spring during the cold phase of the ENSO cycle 
                         (la Niņa) and longer-period ENSO-like oscillations, when strong 
                         southerly winds and an enhanced subtropical anticyclone prevail 
                         over that area..",
  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/",
                  url = "http://urlib.net/rep/cptec.inpe.br/adm_conf/2005/",
           targetfile = "1629-1634.pdf",
                 type = "Understanding long-term climate variations in the SH",
        urlaccessdate = "24 jan. 2021"