How to use the Torrence & Compo wavelet code with custom noise models and confidence levels

F. Auchère, C. Froment, K. Bocchialini, E. Buchlin and J. Solomon

September 27, 2016

Contact: frederic.auchere[at]ias.u-psud[dot]fr

Demonstration program

The Annex of our paper ''On the Fourier and wavelet analysis of coronal time series'' (Auchère et al. 2016, ApJ, 825(2), 110, ADS, arXiv e-print) provides practical details on how to use the Torrence & Compo wavelet code with any noise model (e.g. the one described in Section 5, Equation 26) instead of the built-in white or red noise, and with the global confidence levels introduced in Section 4.

However, typos prevented the in-line code snippets provided in the Annex from running properly. The arXiv version of the paper has been corrected and the code snippets are now fully functional. The method described in the paper as well as the results and conclusions are unaffected.

In addition to these bits of code, you will find here a full demonstration program. Simply run confidence_levels_demo.pro from the directory in which you have extracted the source files and it will produce a simplified version of Figure 9 of the paper. We hope that you will find it useful if you wish to apply the principles described in the paper to your own wavelet or Fourier analysis.

The code (confidence_levels_demo.pro) is written in IDL and requires that you have the IDL version of the Torrence & Compo wavelet software installed. The output should be an .eps Figure that looks like the one below.

Please don't hesitate to contact me should you have any problem with the code.