Synthetic time series generator

[kkappler]

Create a module to generate synthetic time series.

See also aurora issue 97

2014 publication (Neukirch, Maik, and Xavier García. "Nonstationary magnetotelluric data processing with instantaneous parameter." Journal of Geophysical Research: Solid Earth 119.3 (2014): 1634-1654.) is a reference for this work. Also, the Matlab scripts are available, however, the E, H fields are related by the TF, but do not, in that example, appear to be pinned to the Grand Spectrum.

Note that a recent article showing the updated Grand Spectrum is available in Constable & Constable 2023.

• They include a digital archive with the following:

Start Quoted Text from https://marineemlab.ucsd.edu/steve/projects/GrandSpectrum/index.html

• **Download the pdf image: grandspectrum.pdf (276 kB)

Download the zipped data: GSpectrum.zip (37 MB) (recommended)

Download the ascii data: GSpectrum.dat (291 MB) (not recommended - might open the 291 MB file in a new window)

There are 5 columns in the digital file:

Frequency in Hz
Power spectral estimate in nT^2/Hz
One standard error estimate of the spectrum in nT^2/Hz
Frequency resolution in Hz
Number of sine tapers used
Coming soon: The time series and power spectrum code.**

End Quoted Text from https://marineemlab.ucsd.edu/steve/projects/GrandSpectrum/index.html

[kkappler]

TODO:

• Unpack the grans spectrum and plot it in the ipynb on branch fix_issue_262