Please use this identifier to cite or link to this item: https://repositorio.inpa.gov.br/handle/1/19504
Title: Southern oscillation signal in south american palaeoclimatic data of the last 7000 years
Authors: Martin, Louis
Fournier, Marc
Mourguiart, Philippe
Sifeddine, Abdelfatah
Turcq, Bruno Jean
Flexor, Jean Marie
Absy, Maria Lúcia
Keywords: Beach Ridge Record
El Nino-southern Oscillation
Longshore Transport
Palaeoclimate
Palaeoclimatic Data
Rainfall Anomaly
Reversal
Brazil, Rio Doce Coastal Plain
Chira
Issue Date: 1993
metadata.dc.publisher.journal: Quaternary Research
metadata.dc.relation.ispartof: Volume 39, Número 3, Pags. 338-346
Abstract: During strong El Niño events, rainfall anomalies and changes in wind patterns are observed in different regions of South America. Along the central Brazilian coast, during the 1983 El Niño year, the frontal systems were blocked to the south, provoking a reversal of the longshore sand transport. Long-duration reversals of longshore transport were also recorded in Holocene beach-ridge terraces from the Rio Doce coastal plain. This led to the formulation of a model relating these reversals of longshore transport to El Niño-like conditions. El Niño-like conditions are past average climate situations that generate the same perturbations as the strong El Niño events observed during the last decade. They are likely to correspond to the long-duration low phase of the Southern Oscillation. To confirm this hypothesis we compared the Holocene beach-ridge record with other palaeoenvironmental records from regions where strong El Niño events would have a substancial signal as well: (1) water-level fluctuations of Lake Titicaca, (2) a pollen and sediment record in an eastern Amazonian lake, (3) changes of the Rio Xingu discharge in eastern Amazonia, and (4) variations of sand supply at the Rio Piura and Rio Chira outlets in the Sechura Desert. The occurrences of El Niño-like conditions were numerous before 3900-3600 yr B.P., absent between 3900-3600 and 2800-2500 yr B.P., and infrequent after 2800-2500 yr B.P. © 1993 University of Washington.
metadata.dc.identifier.doi: 10.1006/qres.1993.1040
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