A WAVELET ANALYSIS OF PLIOPLEISTOCENE CLIMATE INDICATORS - A NEW VIEWOF PERIODICITY EVOLUTION

Wavelet analysis offers an alternative to Fourier based time-series an alysis, and is particularly useful when the amplitudes and periods of dominant cycles are time dependent. We analyse climatic records derive d from oxygen isotopic ratios of marine sediment cores with modified M orlet wavelets. We use a normalization of the Morlet wavelets which al lows direct correspondence with Fourier analysis. This provides a dire ct view of the oscillations at various frequencies, and illustrates th e nature of the time-dependence of the dominant cycles.