Time scales and trends in the central England temperature data (1659–1990): A wavelet analysis

We have applied the standard wavelet and the adaptive wavelet transform algorithms to the record of the Central England Temperature (CET) from 1659–1990. Peaks in the CET spectra include 7.5±1.0 yr, 14.4±1.0 yr, 23.5±2.0 yr, as well as a previously unreported variation at 102±15 yr. Our wavelet analysis of CET agrees with previous results from Singular Spectrum Analysis (SSA) by Plaut et al. [1995] and gives additional results of variability on longer timescales. The interdecadal and century-scale variability in CET is strongly dependent on the interval of analysis. Estimates of a data trend are also shown to be sensitive to the cutoff timescale of the filter. A cooling of ≈ 0.3°C during 1659–1720 is found relative to the temperatures during the 1800s. The complex time dependence of the actual data cautions against using model-derived representations of natural variability on such long timescales.