ENSO signals in South America: Rains and Floods in the Parana River Region during Colonial Times

PRIETO, MARIA DEL ROSARIO

CLIMATIC CHANGE

Springer

Lugar: Dordrecht, The Netherlands; Año: 2007 p. 39 - 54

0165-0009

Abstract.  Several studies show that the El Niño-Southern Oscillation (ENSO) is an important factor in determining interannual rainfall variability in South America. This signal is detected in the region including Northeastern Argentina, Uruguay and part of Southern of Brazil, provoking big floods in the regional rivers when the event persists until the autumn of the second year.  To check that  this relationship was similar in the past the objectives of this paper were to construct a time series of large floods and precipitations in the Paraná River region from documentary records, during 16th to 18th centuries, and  to evaluate the relationship between the occurrence of ENSO events and the historical record of extreme floods. Considering that the  period 1904-2000 where 11 out floods  of 16 occurred during El Niño events, it can be concluded that the proportion of years with exceptional flow volume in the Paraná River and the years with El Niño events in the 17th and 18th centuries is lower than that of the 20th century.