Analysis of Winter Anomaly and Annual Anomaly Based on Regression Approach

Round 1

Reviewer 1 Report

Comments for author File: Comments.pdf

This article has a few grammatical problems and questionable word choices. See my minor comments in my review.

Author Response

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Reviewer 2 Report

1. The authors statistically analyze winter anomalies in the ionosphere. There have been many studies on winter anomalies, such as [12]-[15] (especially [12] https://doi.org/10.1051/swsc/2018036), but the research in this article seems inconsistent and fails to reflect the innovation. Please highlight it in the article.
2. The Introduction is confusing, and I recommend reorganizing it into three parts as follows: (1) research significance, (2) research status and main issues, and (3) the objective critical points of this part.
3. The author only statistically analyzes the winter anomalies and annual anomalies of TEC parameters. As NmF2 is an important parameter in the ionosphere, especially the main parameter for anomaly research, the author should consider adding statistical analysis of NmF2.
4. Equations 3: The F10.7 uses daily data, and a, b, c, and d are coefficients related to longitude and latitude. How does the author obtain local hourly TEC data for figures 3-6? Please add relevant formulas and explanations.
5. Equation 4: What does TECSLT’ mean? It is not introduced in the article; please check this paper. 
6. The full name should be given when the abbreviation first appears, such as LT (local time). Please check this paper.
7. Line 318, Page 11: The ‘WHC’ abbreviation is in the wrong position.
8. The title of Figure 7: Replace “TEC local time variation curves based on regression equations” with “TEC variations with local time based on regression equations.” The English writing needs to be re-checked and organized. Please check this paper.
9. Most of the figures are unclear, such as Figures 5, 6, and 7; please increase the resolution of these figures.

Author Response

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Reviewer 3 Report

 

The article considers the winter anomaly and (as I see) follows the work [12]. The article shows results in another way: for example, it shows the maps at which the level of F10.7 winter anomaly appears. Then the text step was done and the authors considered the annual anomaly. I think that the main contribution is an assessment of winter anomaly influence to the annual anomaly. The article is scientifically sound, and the experiment design is appropriate, so I think it can be published in Remote Sensing. I have several issues that the authors should take into consideration before publication.

 

1. For me it is unclear, why there is no anomaly in the southern hemisphere (Fig. 9) while [12] indicated that it is possible.
2. I would not recommend summing TEC values, because TEC of 150000 TECU is too weird. Use mean value instead. I understand that it is just an issue of normalization, but it prevents comparison with other papers.
3. I would think that AI should be (TEC12-TEC06)/[0.5(TEC12+TEC06)]. For me, it is also not clear why ????? 12 -????? 06 represent the total contribution of the winter hemisphere to the annual anomaly. I would think that it should be ????? 12 -???N? 06. And I would think that WHC should be (????? 12 -???N? 06 )/ [0.5(TEC12+TEC06)]. I think that the formula (and if possible references) should be discussed in detail.
4. Because you used different LT for anomalies, you should indicate their (anomalies) definitions more clearly. I would say that it is also an interesting point. The results for different LT are due to different atmosphere dynamics during winter and summer (and shorter daytime). It could also be affected by altitudinal effects [Klimenko et al., 2019, 10.1134/S1990793119040080] (due to different solar illumination) of winter/annual anomalies.
5. Try to avoid abbreviations (like FTV – in the conclusion I have already forgotten what it means). They make reading difficult. 
6. Figures are of too low resolution (seems that it is <100 dpi), and they are blurred. Their quality must be increased. 
7. 3.3 – should be “Annual anomaly” rather than “annual anomaly”.
8. I do not think that Fig. 11 is necessary. It is quite clear just from the line 286. 
9. Axis caption should be value and units (f107p, s.f.u.). Do not show units just after digits.

 

In general it is appropriate (understandable), but requires check for misprints.

Author Response

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Round 2

Reviewer 2 Report

1. As previous comment 3, the author only statistically analyzes the winter anomalies and annual anomalies of TEC parameters. As NmF2 is an important parameter in the ionosphere, especially the main parameter for anomaly research, the author should consider adding statistical analysis of NmF2. Therefore, I suggest that the author include the research objectives of this paper in the introduction, while the analysis of NmF2 should be considered in future work and added an explaination at the end of the conclusion.

 

2. Equations: "TEC" should not be italic but traditional.

 

3. Equation 6: "FTVs" should not be italic but traditional.

 

4. Figure 5 should not be spread across pages.

 

5. All abbreviations such as "LT" should be used after the abbreviation description appears.

 

6. As previous comment 6, the full name should be given when the abbreviation first appears, such as TECM-GRID and TECM-MF. Please check the whole manuscript.

Author Response

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Reviewer 3 Report

The paper was improved and now it can be accepted

 

Author Response

Thank you for your comments!