On 5 September 2022, an Ms6.8 earthquake struck Luding, China, causing extensive damage. This study analyzed near-surface atmospheric electric field (AEF) data collected 15 days before the earthquake, along with various other data sources. The authors identified nine possible AEF anomalies related to the earthquake. They confirmed four of these anomalies to be closely linked to the earthquake, while ruling out the other five. The mechanism behind these anomalies involves the transfer of positive charge carriers from underground high-stress areas to the surface, ionizing the air and disrupting the atmospheric electric field. This research is interesting and provides insights into identifying seismic AEF anomalies and understanding the pre-earthquake processes between the Earth's crust and the atmosphere.

My opinion is that the work must be published after some points are clarified.

Figure 2. It is not clear if the figure represents a typical day of FW-AEF or a daily mean curve.

Lines 172-175. Among magnetic indices, only Dst is used. However, some penetrating field currents can appear in middle latitudes on occasion of some auroral activity. It would be more conservative to consider also AE index: when it is lower than 100, it is practice to neglect the presence of that kind of currents. Could you please check if AE is lower than 100 in the period of interest?

Figure 3. It shows at its top panel the daily mean values of Dst and SSN. However, this value for Dst is not appropriate and cannot well characterize the level of magnetic activity. It would be more appropriate its hourly value.

Figure 3. How did you define the 0 value of AEF?

Minor correction

Line 344. Please change “were” with “was”.

The investigation of Wu Lixin et al. proposes a very interesting work on the analysis of atmospheric electric field with 4 ground stations in China before Ms6.8 Luding earthquake occurred on 5 September 2022. The observations of atmospheric electric field before the earthquake are rare in literature especially for lack of specific instrumentation on active seismic sites. So, this paper is a crucial contribution to the research field of the understanding of the lithosphere - coversphere - atmosphere and ionosphere coupling (LCAIC). Overall the authors extracted several anomalous variations of electric field from the stations and scrutinise among the weather conditions which anomalies are likely due to weather (e.g., low clouds in atmosphere) ruling out such anomalies and considering the remanent ones for possible seismic source. The authors integrated the investigation also with Microwave Brightness Temperature of the area discussing how the P-holes can explain the detected anomalies in the light also of the stress field of the area. Finally the authors depicted 4 anomalies as likely induced by the p-hole and air ionization due to seismic activity. Considering all of this I recommend the paper for publication in NHESS after some minor revision and few clarifications.

Specific questions/minor points:

• Line 9. I think that “four discretely distributed sites” can be simplified in “four sites” as intrinsically “discrete”
• Line 21. The expression “were believed to be” is not so scientific, so I suggest to delete and introduce the sentence in this way: “A possible mechanism of negative AEF anomalies before Luding EQ is supposed that positive charges carriers [...]”
• Line 23 and several occurrences in the manuscript. I think the term “aground” is not proper and I would suggest to change in “above the ground”.
• Line 30. Instead of “In the state of nature the operation of Global Electric Circuit” you can simply write: “In nature, the Global Electric Circuit”
• Line 36. Instead of “detected” I suggest to use “claimed” to provide some caution.
• Line 37. Please replace “the field mill electric field instrument” by “the field mill instrument” otherwise there are too much repetition of electric field in the same sentence.
• Lines 38-44. Please insert some cautions when report the previous studies, for example at line 43 instead of a typical AEF I suggest to write a possible AEF.
• Line 78. Please, revise the sentence, while you say humidity speaking of atmospheric particles? Maybe some concepts are missing...
• Line 93. Could be worth to mention that Longmenshan fault was the source of two majior earthquakes in last decades, Lushan 2013 and Wenchuan 2008, the last one with catastrophic impact of lives.
• Line 94. I suppose that “observations” stays for “observatories”
• Line 94. You need to introduce the stations/observatories. You can introduce a sentence like: “The atmospheric electric field has been analysed using four stations called GAR, GUZ, SWG and LES.
• Table 1. I would suggest to add a column with the altitude of the station after the latitude, even though you reported this information in the text.
• Line 128. “including but not only”, or “among them”
• Line 131. Please, improve the introduction of ERA-5, saying for example that is reanalysis of atmospheric observations from multiple sources (ground, satellite, etc...) produced for climatological investigations...
• Lines 148-149. I think that these two sentences can be rephase better even though mostly right for scientific concept. If I understand the meaning I would suggest: “Characterizing the FW-AEF background is an important, in order to determine the periodic variation of natural AEF in the region under investigation. Consequently, it is necessary [or crucial] to study the characteristics of the FW-AEF to better identify seismic AEF anomalies.”
• Line 154. I suggest t change “aground” in “above the ground”
• Line 174. The signs of Dst are inverted and it is better insert unit of measurement (nT). A simpler notation would be: “-50 nT < Dst < -30 nT”
• Line 179 (and 180). I think it’s more proper to call these data “climatological data” instead of “remote sensing data” even though they are retrieved especially from remote sensing satellite.
• Line 187. I warmly suggest some caution to the authors. Please, change “it had been influenced by seismic activity” in “it had been influenced by seismic activity”
• Line 236. I suggest to substitute “geological preference of” with “geological influence on”
• Line 292 (and 297). Peroxy-defects (not “deficient”)
• Line 299. I think “accumulation” would be more proper term than “aggregation”
• Lines 311-315. I think that also other hypotheses based on difference of electrical propertied of electron with higher mobility than P-holes (separated at source as stated by authors) are possible according to Freund, et al. 2021). Can the authors comments?
  • Freund, F.; Ouillon, G.; Scoville, J.; Sornette, D. Earthquake precursors in the light of peroxy defects theory: Critical review of systematic observations. Eur. Phys. J. Spec. Top. 2021, 230, 7–46. https://doi.org/10.1140/epjst/e2020-000243-x
• Figure 7. Please insert the vertical scale with unit of measurements and preferable also horizontal one.
• Figure 8 / lines 348-349. Why did you plot the wind field from 3:00 UT on 22 August 2022 and not from 1:00 UT, i.e., before the MBT map at 2:00 UT? Can you add this information, please?
• Line 365. As suggested before please use some caution: “likely had been influenced by seismic activity” .
• Line 377. “considered to be possibly associated”

Suggested literature that may be integrated:

• Freund, F.T., Takeuchi, A., Lau, B.W.S., Al-Manaseer, A., Fu, C.C., Bryant, N.A., Ouzounov, D. Stimulated infrared emission from rocks: assessing a stress indicator (2007) eEarth, 2, pp. 7-16.
• Liu, Shanjun; Cui, Yi; Wei, Lianhuan; Liu, Wenfang Ji, Meiyi. Pre-earthquake MBT anomalies in the Central and Eastern Qinghai-Tibet Plateau and their association to earthquakes. Remote Sensing of Environment, 298, 113815, 2023. Doi: 10.1016/j.rse.2023.113815