%0 Journal Article
%T ENSO influence on tree ring data from Chile and Brazil
%A Nivaor Rodolfo Rigozo
%A Daniel J. R. Nordemann
%A Ezequiel Echer
%A Luis Eduardo Antunes Vieira
%J Geof¨ªsica internacional
%D 2004
%I Universidad Nacional Aut¨®noma de M¨¦xico
%X Wavelet spectral analysis was made in tree ring width data from Brazil (27¡ã11¡¯S, 51¡ã59¡¯W) and Chile (49¡ã12¡¯S, 73¡ã50¡¯W) over the period 1876-1994. Southern Oscillation Index¨CSOI, representative of ENSO phenomena, and Global mean Surface Air Temperature (GAST) data have been analyzed by wavelet transform. A 2-8 year range was selected. Fluctuations were observed in all data, as expected; these indicate the ENSO imprint on tree-ring data. Strong and weak amplitudes alternate, and frequency shifts in the signal were observed. The strongest signals were observed in the 4-8 year band in Chilean tree ring data, near 1906-1920 and 1930-1950, and in Brazilian tree ring data in the 6-8 year band near 1906 and 1950. SOI spectrum presented a larger number of intense amplitudes as expected, and GAST spectra showed high intensity only in 1906-1928, in the 5-8 year band. The results show a clear ENSO influence on tree growth.
%K Tree ring data
%K time series
%K wavelet spectral analysis
%K ENSO phenomenon
%U http://www.geofisica.unam.mx/unid_apoyo/editorial/publicaciones/investigacion/geofisica_internacional/anteriores/2004/02/Rigozo2.pdf