Inconsistent results?

[lovechang1986]

I copy the code to notebook on my machine and tested.
The result as this png:

As the official result is:

pycwt document

The biggest difference is the minimum value of the original data from document is letter than -2, but my test is greater than -2? Is that why they had inconsistent results?

[tompc35]

The difference between the two plots arises in this step of the tutorial

Optionally, we could also rectify the power spectrum according to the suggestions proposed by Liu et al. (2007)[2]
power /= scales[:, None]

Removing this optional step will give the official result for the Nino-3 SST example. However, see Liu et al. (2007) for a discussion of bias in power spectra given by traditional wavelet analysis. Their Figure 4 specifically addresses the difference between these two plots.