Peer review of: Evidence of ubiquitous Alfvén pulses transporting energy from the photosphere to the upper chr (2019)


RR2
Reviewers' comments:
Reviewer #1 (Remarks to the Author):
Report on Manuscript #NCOMMS-18-26662A-Z
Title: Evidence of ubiquitous Alfvén pulses transporting energy from the photosphere to the upper chromosphere
Authors: J. Liu, C. J. Nelson, B. Snow, Y. Wang, R. Erdélyi
This is a revised version of a previously submmited manuscript. The original manuscript contained strong claims about propagating Alfvén pulses found to carry enough energy to sustain the high temperatures of quiet regions in the entire upper atmosphere. These claims were not supported by the presented evidence.
The authors have now lessened their claims and present a fair manuscript where the finding and properties of photospheric and chromospheric short-lived swirls and their statistical relationship are presented.
An estimate about the energy potentially to be carried by these events is presented. The magnitude is high enough for these events to be considered important in the energy transport across the solar atmosphere.
The authors employ state-of-the-art instrumentation with data of the
highest available quality. A multi wavelength multi instrument analysis is performed. Also, advanced numerical computations were carried out trying to mimic the generation and propagation of the disturbances thought to be responsible for the observed swirl propagation.

I find these results are certainly of interest to the solar community and perhaps also to readers from other fields. The claims are now in accordance with the level of evidence being presented. For these reasons, I recommend the manuscript for acceptance in Nature Communications.
Reviewer #2 (Remarks to the Author):
The authors responded various comments and questions by the referee seriously to some extent, which improved the paper very much. Only one concern is the relation between the swirls and the small scale vertical magnetic flux tubes. The authors analyzed the relation between SST data and HMI LOS magnetogram data, but found only 3.3% clear relation between them as shown in Figure 1 of the response to the reviewers comment. The present referee is positive for the publication of the basic results on the discovery of many swirls in the chromosphere and photosphere and their intimate relation. However, the relation between swirls and vertical magnetic flux tubes are remained to be examined in detail in future. Hence I would like to recommend the authors to publish all results including the relation to HMI LOS magnetogram data.
Reviewer #3 (Remarks to the Author):
While the revised manuscript addresses some of my concerns in the previous report, major concerns still remain. Therefore, unfortunately, I cannot recommend publication in Nature Communications.
In particular, the study does not adequately address the poor correlation of the swirls detected at various solar atmospheric layers. The discussion of the energy shortage in the detected waves is contradictory by first claiming significant energy and than indicating a required energy for mid- chromospheric heating that is 3-10 times larger than the estimated wave energy flux.
The paper does not provide adequate detail on the numerical method and parameters used in the present study, which does not allow assessing the numerical adequacy of the model.