Spectral Analysis of Reconstructed Summer Temperature Variations

Annual average summer temperature variations can be reconstructed using dendrochronology methods (analysis of tree rings). We perform spectral analysis of temperature series reconstructed for the last 3000-4000 years and for various geographical locations both in the northern and southern hemispheres. Spectral properties of these data series were calculated using wavelet decomposition and methods of higher order spectral analysis. The obtained spectral features are compared with the known solar periodicities. No evident correlation between the reconstruted temperature and the 11 year solar cycle is found.