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In this work we apply the wavelet transform to the Pelotas (southern Brazil) total annual rainfall series . Classical, wavelet and cross-wavelet analyses were performed in the El Niño Southern Oscillation (ENSO), Quasi-Biennial Oscillation (QBO), sunspot number (Rz) and Pelotas rainfall time series. Classical spectral analysis for Pelotas has shown a large number of short periods -between 2.2-5.6 years (yr) and periods at 8.9, 11.7 and 24.9 yr. Further, we have found that the Pelotas rainfall wavelet spectrum shows the most significant periodicities around 2-8 yr, but they have an intermittent character. Cross-wavelet spectrum showed that: rainfall and QBO series are correlated at 2-3 yr (QBO) scales and this cross-power is continuous along the time series interval; rainfall and SOI have higher cross-power around 4-8 yr, but this signal is sporadic; rainfall and sunspot number (Rz) showed higher cross-power around the 11-yr solar cycle period, but this crosspower is sporadically high and low; finally, the rainfall cross-spectrum with the double sunspot number (Rz22) revealed a high cross-power around 20-22 yr which is more persistent in duration, compared to the 11-yr period. These wavelet results are compared with classical spectral analysis and with previous work results. We concluded that the phenomenon that influences most of Pelotas rainfall variability is ENSO, but only a minor part of the variance (∼30%) can be described by a simple multi-linear dependence on solar/ ENSO/QBO phenomena, this result could imply that non-linear coupling among sun and internal climatic variability (QBO, ENSO) has an important role in the local/regional climate variations.

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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.