Tree-ring width wavelet and spectral analysis of solar variability and climatic effects on a Chilean cypress during the last two and a half millennia
N. R. Rigozo1,2,3, D. J. R. Nordeman2, E. Echer2, L. E. A. Vieira2, M. P. S. Echer1,2, and A. Prestes21Faculdade de Tecnologia Thereza Porto Marques – FAETEC, CEP 12308-320, Jacareí, Brazil 2National Institute for Space Research – INPE, S.J. Campos, Brazil 3LARAMG – Laboratório de Radioecologia e Mudanças Globais/Departamento de Biofísica e Biometria da Universidade do Estado do Rio de Janeiro, Rio de Janeiro – RJ, CEP 20550-013, Brazil
Received: 28 Jun 2005 – Discussion started: 24 Aug 2005
Abstract. Spectral and wavelet analysis were performed on a tree ring width time series obtained from a 2500 yr old cypress tree (Fitzroya cupressoides) from Costa del Osorno, Chile. The periods for analysis were selected at 95% confidence level. Both periodicities characteristic of solar activity and climatic variations were found in this tree ring width series. The 11 and 22 years solar cycle periods were present in tree ring data with a confidence level above 98%. This indicates the solar modulation of climatic variations is being recorded by the tree ring grown. However wavelet analysis shows that these are present only sparsely. Short-term variations, between 2-5 years, are also present in tree ring data, and are shown by wavelet maps to be a more permanent characteristic. This time scale is a signature of ENSO events. Long-term variations, above 200 years, are also present in tree ring data. The spectral analysis performed in this work shows that this species has the ability to record solar-ENSO variations that seems to be affecting the local environment of tree growth, and also that this region was influenced by ENSO events at least in the past 2500 yr interval covered by this study.
Rigozo, N. R., Nordeman, D. J. R., Echer, E., Vieira, L. E. A., Echer, M. P. S., and Prestes, A.: Tree-ring width wavelet and spectral analysis of solar variability and climatic effects on a Chilean cypress during the last two and a half millennia, Clim. Past Discuss., 1, 121-135, doi:10.5194/cpd-1-121-2005, 2005.