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 (GET) 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 approximate to 0.3 degrees 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.