Ionospheric Modulations in BIRO spectra

I interpret the banding patterns observed by Jim Sky in BIRO spectra obtained April 28, April 29 and and June 22 as possible Ionospheric Modulations.

I refer to Genova, Aubier and Lecacheux  1981 :


In this paper the authors  describe, among others, a type of modulation due to the Terrestrial Ionosphere.
This modulation is superimposed on other existing Jovian radiation features such as arcs, modulation lanes, or interplanetary scintillations.

These are some of the characteristics of this type of modulation:

Negative drift most of the time, with strong modulation depth
Their frequency drift and spacing varies with time and frequency
The drift rate increases with frequency
Typical values: 20 Khz/s drift at 20 Mhz, 0.5-1 Mhz frequency spacing, 1 minute time spacing

The image they present reproduces very poorly in the PDF version of their paper :


 Plotting the location of these features on the CML/Io Phase diagram :

The authors see "...no enhancement of any particular region of the plane..."
Supporting a non-Jovian origin for this type of modulation

 This is the diagram for all emissions :


 In support of an ionospheric origin, they comment :


I repeat  the June 22 observation, showing a general agreement with the Ionospheric Modulations described by the authors.


I have noticed patterns, in Nancay spectra, such as the following June 10 IoA event.
The banding is clearly visible in Left Hand circular polarization only.
Is this an Ionospheric Modulation ?



Victor Herrero
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