Comparative Study of the Es Layer between the Plateau and Plain Regions in China
, Lehui Wei 1, Qiong Tang 2, Wengeng Huang 3, Hua Shen 3, Tongxin Liu 1, Guobin Yang 1, Chen Zhou 1 and Zhengyu Zhao 1,2
Round 1
Reviewer 1 Report
The manuscript compares Es layers at two nearby locations in China using ionosonde measurements. The occurrence probabilities of foEs and hoEs along with diurnal and seasonal variability are analyzed for the data collected during 2018. As expected, similarity exists in the characteristics of Es at two locations. However, differences also exist, and the authors conclude that the observed differences might have been caused by the gravity waves.
In my view, the manuscript contains originality of work and must be allowed to publish however, some clarifications and improvements must be included in the draft as pointed out below.
I recommend for minor revision based on the following comments;
Major Comments:
1) Authors have cited the work of Pietrella et al., 2014 in the introduction. Most of their results in this study are similar to Pietrella et al., 2014. However, I could not see discussions related to it, specifically, the similarity and differences between the results from two studies. I suggest the authors to consider this and discuss in the manuscript.
2) Ln 81: The description of the Table-1 does not include total number of measurements. However, it is given around Ln 107. To avoid confusion, please bring up those descriptions to around Ln 81, or bring down Ln 81 descriptions to Ln 107 paragraph.
3) What quality control measure was taken in determining Es layers other than setting the threshold 3 MHz? How was the sporadic Es differentiated from blanketing Es? Were any criteria used? Or, are these occurrence probabilities include both categories of Es? I suggest to describe them in detail.
4) Since the two stations have different versions of the ionosonde, were the auto scaling / manual scaling or a combination of two used in this study? Are these from either ARTIST-4 or ARTIST-5, or any site-specific software? I understand there are differences among these versions of software in identifying parameters. Please describe those details so that readers can understand more about your results in comparison with other published results.
5) Ln 200: In figures 8 and 10, it is better to mark "zero values" with different color other than blue (e.g., gray). According to the current setting, it seems very difficult to identify which period or periods are “zeros” and which periods are "non-zero low values".
6) Ln 242: What is meant by “weekday tidal wind”? Does it refer weak diurnal tidal wind forcing?
7) It is stated that the nighttime winter anomaly might have been caused by gravity waves. Were the authors able to verify this by means of any other way in this region?
Minor Comments:
Ln 63: Please check the name of ionosonde station. Isn’t it Gibilmanna?
Ln 64-66: Please clarify the meaning of the two sentences. Are these sentences meant for the following?
Although the diurnal, seasonal and spatial variability of the Es could be explained partially in many studies on mid-latitude Es layer, it is worthy to further study the characteristics of the Es layer, especially for the coupling of the Es layer and lower atmosphere.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper concentrates on providing information about Es layer of the ionosphere from ionosonde data. Although the data is useful, but it provides not much innovative information to the reader.
The conclusions aren’t thoroughly supported by the results, but mainly concluded from other studies.
The reliability of the results is confirmed by consistency between the data obtained from two ionosondes, while the true reliability is obtained from comparison of results with results from totally different technique, e.g. radio occultation.
The language needs a lot of improvement. There are many mistakes/ typos which should be corrected.
Some other suggestions are:
Figure 1: It’s good to explain how Es layer information is extracted form the ionogram data
Figure 2: why is probability of Es layer higher in Zhangye station compared to Beijing station?
Figure3: These are the mean values over one year, Standard deviation should be accompanied for complete picture
Other corrections/ suggestions are included within the pdf file.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
This paper provides a study of the comparison of the occurrence of Es in two locations in the mid-latitude. One is in plateau; one is in plain. They find that although the Es occurrence is similar in seasonal variation, there is difference for Es occurrence inside several months and diurnal variations. They finally attributed this to the difference of gravity wave activity. The topic is interesting, and never been carried out (or at least emphasized) before. However, there is some aspects missing in the discussion part, which can harm the foundation of the paper. Therefore, I recommend the paper to have a major revision before it is suitable for publication.
Line 10 add ‘forcing’ after ‘lower atmosphere’
Line 14 add ‘,’ before ‘respectively’
Line 32 this is nor right. Razada et al., 2015 shows that the time duration o Es can be 8-hour
Line 33 Es intensity even stronger than F layer peak?? The author shall provide reference on this statement.
Line 35 it is the Es in the mid-latitude that can be attributed to wind shear theory, please add ‘mid-latitude’ to be specific.
Line 43-63 the author shall also add the aspect that the Es is also closely correlated with the sporadic metal layer and provide some references. Such as Dou et al., 2013, and similar studies in the North America (the author can search by themselves using google scholar to see what papers cite Dou et al., 2013)
, , , , and (2013), Sporadic and thermospheric enhanced sodium layers observed by a lidar chain over China, J. Geophys. Res. Space Physics, 118, 6627– 6643, doi:10.1002/jgra.50579.
Line 120-122 this sentence is too long and orally written. Please end the sentence after 18 LT. And start the sentence from ‘They finally decrease slowly until sunrise’
Line 177 add ‘,’ before ‘although’
Line 239-248 the author can also compare their results with previous studies in the similar latitude but different longitude, such as studies focusing in the north america area and other papers focusing on Europle station Es. The author shall use more sentences for the comparison, not just a single sentence to barely mention it, like they did in lines 258-260.
Line 251 seasonal character in summer? Do you mean Es occurrence peaks in summer??
It shows the occurrence probability of the Es layer at Zhangye has obvious winter anomalies.
The author mentioned that Es in Zhangye also has some occurrence in winter and spring. But here they only call it as winter anomaly, which is not suitable. Winter anomaly is easy to cause confusion and misunderstanding because in the ionosphere area, there is also NmF2 winter anomaly. Please change words to better include both winter and spring.
Line 269-277 Strictly speaking, Chu et al., 2014 is not the numerical simulation. They only calculate the transport term of the Fe+, which is not the full picture of the continuity equation of the Fe. Furthermore, solving the metal ion separately is not correct, which lacks the chemistry from the corresponding neutrals. The author shall check Cai et al., 2019 and references inside the paper, which solve the full continuity equation of sodium (Na) and sodium ion (Na+), an important component in Es, as well. Note that the different metal ions in the Es behavior almost similarly. Furthermore, the Figure 4 in Cai et al., 2019 can help explain the seasonal variation of Es.
Cai, X., Yuan, T., Eccles, J. V., & Raizada, S. (2019). Investigation on the distinct nocturnal secondary sodium layer behavior above 95 km in winter and summer over Logan, UT (41.7°N, 112°W) and Arecibo Observatory, PR (18.3°N, 67°W). Journal of Geophysical Research: Space Physics, 124, 9610– 9625. https://doi.org/10.1029/2019JA026746.
Furthermore, the author has cited most of the gravity wave papers in the stratosphere. While Es is the phenomenon above MLT. How can author conclude that the waves in the low atmosphere can determine a phenomenon above MLT? Due to the wind filtering effect, maybe the gravity wave activity in MLT region does not necessarily stronger if the wave activity in the lower atmosphere is stronger. The author shall at least state that they have, or they try to seek gravity wave information between 80 and 120 km in Beijing and Zhangye. For example, any measurements that can provide the neutral temperature or wind over these two locations in the MLT region?? Additionally, there is also the description of gravity wave signature in Cai et al., 2019, which can also help the discussion of the gravity waves behavior in the current paper.
Line 296 refer 23 mainly studied the tides and planetary waves influence on Es, and barely mention one time that gravity waves might influence Es, which is not satisfied with ‘gravity waves play a critical role in the formation of Es’, please delete it
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors have fulfilled the suggestions/ comments from previous revision. The paper is worth being published after minor revisions in the English and typing.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
There are still some places need to be improved before it is ok for publishing
My commes are based on lines in track changes
For the Figures, apart from the Figure 1, why the following figures are with 21, 32??
Line 74 what impact of the solar activity??
Line 379-396 the author shall add several statements to clarify that gravity waves in MLT region are in small-scales. While those previous observations resolution are huge (5 degree in latitude or longitude). That is the reason why beijing and zhangye's results are almost similar based on previous studies
Line 395 remove 'might' because there is another 'might' in the later part of the sentence
Line 401 remove 'in seasonal variation' and replace it with 'in the whole year'
Line 402 remove 'there is only slight difference'. This is too orally written!
Line 403 add ', which is almost simialr to Wang et al.' after 'in the diurnal variation'
Author Response
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