Long-Period Fluctuations in El NiñO Amplitude and Frequency Reconstructed from Tree-Rings

  1. David H. Peterson
  1. Joel Michaelsen

Published Online: 23 MAR 2013

DOI: 10.1029/GM055p0069

Aspects of Climate Variability in the Pacific and the Western Americas

Aspects of Climate Variability in the Pacific and the Western Americas

How to Cite

Michaelsen, J. (1989) Long-Period Fluctuations in El NiñO Amplitude and Frequency Reconstructed from Tree-Rings, in Aspects of Climate Variability in the Pacific and the Western Americas (ed D. H. Peterson), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM055p0069

Author Information

  1. Department of Geography, University Of Californiasanta Barbara, Ca 93106

Publication History

  1. Published Online: 23 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875900728

Online ISBN: 9781118664285

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Keywords:

  • Climatic changes—Pacific Area.;
  • Paleoclimatology—Pacific Area.;
  • Climatic changes—West (U.S.);
  • Paleoclimatology—West (U.S.);
  • Atmospheric carbon dioxide.

Summary

Tree-ring records from arid-site conifers in the southwestern United States and northwestern Mexico were used as proxy evidence in reconstructing a 400-year, annual El Niño series. The reconstruction was compared to historical record and modern instrument records for verification. It shows that El Niño has been in existence for at least 400 years and that it has consistent fluctuations in amplitude and frequency over 80–100 year time scales. The fluctuations are characterized by a progression of the predominant frequency from about 0.1 cpy (cycles per year) to about 0.35 cpy (10-year to 3-year period). Amplitudes grow as events become more frequent, peaking when the frequency is in the 0.15 cpy to 0.25 cpy range (4-6 year period) and then declining rapidly as the frequency approaches 0.35 cpy.