Evolution of DET (a, b) and LAM (c, d) obtained from the SSN2 for both filtering strategies (grey dots): FFT (a, c) and EMD (b, d). The continuous line represents a smoothed version of both DET and LAM. The shaded areas highlight the times at which significant mismatches in the evolution of DET and LAM are observed. The orange curve represents a rescaled version of the SSN2 to help the reader identifying the solar cycles. The horizontal blue lines represent the 95% confidence level.