Tonga Eruption Grape Data by AB4EJ

What is on these plots: the upper trace is the waterfall showing spectrum 10 Hz wide (“narrow”). The strongest signal has been emphasized in red. The lower trace is relative amplitude (unitless and non-calibrated).

2022-01-14 – the day before the explosion, as a baseline. In the upper left, you see the standard deviation of the spectrum data for the day, which I use as a measure of ionospheric activity.

2022-01-15 – day of the explosion – according to various papers, a wave came through North America after 1400Z (if I understand correctly). Note the higher standard deviation for the day, which shows a combination of the Tonga pulse plus higher geomagnetic activity that day.

2022-01-16 – day after the explosion, things are back to normal; standard deviation back down to around 14.

HOW TO REPRODUCE THESE PLOTS:

Download the Box data to your local drive; ensure that it has a directory structure as shown in the .emz file (in this example, you have downloaded to the D: drive).

The most critical thing is that the directory structure must be what the program expects; it should already be set up this way in the ch0 folder.

Set the variables in the program:

dataDir = "D:\\Tonga_AB4EJ"

metadata_dir = dataDir + '\\ch0\\metadata'

The variable dataDir must point at the directory above the one that contains ch0.

The variable metadata_dir must point at the directory that contains the file drf_properties.h5 .

Using  the program

Run python program plotspectrum.py. (Note that you must have Digital RF installed. Best way to do this is to work in a virtual environment, then do:  pip install digital_rf )

Program will prompt for a date. To see Jan 14, here enter:  2022-01-14

You should get a plot like shown under point 1, above. Note that the program is quite slow and may take 5 – 10 minutes to read the file & create the plot.

If you get the following error…

ValueError: No channels found: top_level_directory_arg = C:\Users\bengelke\Box\share\Tonga_AB4EJ1. If path is correct, you may need to run recreate_properties_file to re-create missing drf_properties.h5 files.

… it usually means that (a) the directory structure is not exactly correct, and/or (b) there is a typo in one of the directory settings dataDir or metadataDir.