Dear Authors,

I am coming back to you on the status of your paper. The paper contains results which are interesting and of potentially importance for the ionospheric and GNSS community. In accord with the referees’ comments I suggest a revision.
Please, consider carefully and discuss in the revised version of the manuscript comments of both referees. One of them and me will revise the manuscript again.
Kindest regards
Yours sincerely
D. Buresova

Dear Authors,

Thank you very much for your response to the referees’ comments and for work you did when improving the manuscript. However, there are still technical corrections requested. Please, read once more the manuscript carefully to be sure that all misprints, grammar or spelling errors are removed (e.g., Page 22: „ For March 2015…“ instead of „… march 2015“; „…epoch wise…“ (Page 3) and „…epoch-wise…“ Pages 5 and 12, etc.) and meaning of abbreviations are right/clear (e.g., “(eq.)”in the caption of Fig.14) according to the comments of the Referee#2 enclosed below.

Referee#2
TECHNICAL CORRECTIONS Here, I will only present those technical corrections that apply to larger parts of the manuscript. Please see the attached version of the manuscript for more specific comments.
• Throughout the document, please check the correct syntax for referring to figures, sections, tables, etc. See https://www.annalesgeophysicae.net/for_authors/manuscript_preparation.html • Please check the captions of figures and tables. Sometimes there is a period at the end, sometimes not. C3
• Please introduce abbreviations when a term is mentioned the first time, then use the abbreviation afterwards (e.g. LEO on page 1, line 2 and line 22. Also GPS, GRACE, GOCE, TEC,...)
• Please check again all citations. There are several cases of wrong parentheses (e.g. page 16, line 20). • Please check capitalization (GRACE, March, Gauss,...).
• Please check the section names for consistent capitalization (e.g. 3.4 vs. 3.5), furthermore, 2 and 2.1 should not have the same title.
• I am not sure if it should be “reduced dynamic orbit” or “reduced-dynamic orbit”. I mostly found the second version in literature. You mostly use “reduced dynamic orbit” except for the caption of Fig.1.
• It should be “F10.7 index” and “Kp index”. • I am not sure about the meaning/sense of “(eq.)”, e.g. in the caption of Fig.14. • Please check the use of hyphens, e.g. epoch-wise, ROTI-based, derivativebased...

The Referee has reviewed the manuscript again and there is the Referee´s conclusion:

Dear editors and authors,

thank you for the revised manuscript. My major concerns of the first review were adequately addressed. Furthermore, the figures are now of a better quality.
However, in my opinion, the manuscript still requires technical corrections. This is due to many spelling errors. I feel that not all of my technical corrections have been carefully revised and I suggest to work through the whole document again with respect to structure, grammar and spelling.
Apart from that, I believe this is an important topic and the authors found interesting results.
Kind regards, the reviewer

After the conscionable technical correction, I´ll recommend the manuscript to be published in Annales Geophysicae.
Kindest regards

Yours cordially
Dalia Buresova