Wavelets and Solar Magnetic Activity I: Wavelets on the Edge

Abstract

The traditional continuous wavelet transform is plagued by the cone-of-influence, ie wavelets which extend past either end of a finite timeseries return transform coefficients which tend to decrease as more of the wavelet is truncated. These coefficients may be corrected simply by rescaling the remaining wavelet. The corrected wavelet transform displays no cone-of-influence and maintains reconstruction as either edge is approached. As an application and example, we present the corrected wavelet transform of the (derectified) yearly International Sunspot Number, R_i, as a measure of solar magnetic activity, and compare the yearly solar magnetic power with Oerlemans' glacial global temperature reconstruction.