Dear Dr. Afolayan, dear co-authors,

Thank you very much for submitting your paper to the Annales Geophysicae as well as for valuable work you did when preparing the manuscript. It is well known fact, that phenomenon of spread F is interesting and important for ionospheric community, as its occurrence effects modern communication and navigation technologies.
Now I am coming back to you on the status of your paper. First of all, thank you for the response to referees suggestions. The addressed referees are working for the long time in the field and provided very valuable comments, and I believe that their comments will be useful also for your future investigations. Two referees suggested major revision of the paper. My suggestion is the same.
As the paper contains interesting observational results, which contribute to our knowledge on the spread F phenomena, I suggest to improve the manuscript according to the comments of the referees and send to us again. Please, highlight in the improved version all changes you introduced. Two of the referees and me will read the revised manuscript once more.
Kindest regards

Yours cordially
Dalia Buresova

Dear Authors,

Thank you for sending us your improved article and giving us the chance to consider your work. Your article was read by me and once again by the assigned external reviewer. I am pleased to make a provisional offer of publication, if you are able to answer/accept the following additional minor comments:

Line 480: it would be good to support your statement about plasma irregularity effects on GPS by some references, e.g.:

Aarons, J., M. Mendillo, and R. Yantosca, GPS phase fluctuations in the equatorial region
during sunspot minimum, Radio Science, Volume 32, Number 4, Pages 1535-1550, 1997.
or
Jiao, Y. , YT Morton, Comparison of the effect of high-latitude and equatorial ionospheric scintillation on GPS signals during the maximum of solar cycle 24, Radio Science, Volume 50 Issue 9, 886-903, DOI: 10.1002/2015RS005719, 2015.

Line 573: what do you meant when writing “…during the manual observation of the plasma…”. It means that the ionograms used were manually scaled or it has some other meaning?

Line 574: there is term commonly used in the ionospheric community “ordinary/extraordinary trace” instead of “main trace”.

Kindest regards

Yours cordially
D. Buresova