Oceanic Responses to the Winter Storm Outbreak of February 2021 in the Gulf of Mexico from In Situ and Satellite Observations

Round 1

Reviewer 1 Report (New Reviewer)

Dear Editor,

The article Oceanic Responses to 2021 Winter Storm Uri in the Gulf of Mexico from In Situ and Satellite Observations is an original work.

The Authors described in Abstract the aim of their research in the words: … Our study demonstrates the utility of publicly available datasets for studying the impact of winter storms on the surface ocean.

The reviewer presents a general remark to the article, which is its 31-page volume. The above comment should be considered by the Editor and in this matter, I leave the decision to the Editor and the accepted practices in the Publishing House.

The review focuses on the formal side of the article and does not engage in polemics and discussions on the considerations adopted by the Authors because it determines the originality of the issue in the article. Considering the proposed solutions I accept it with appreciation.

The following observation require to draw attention and response from the Authors:

1.       Abstract. According to the example pattern of writing MDPI articles, abstracts should give a pertinent overview of the work. The following style of structured abstract should be use but without headings: (1) Background; (2) Methods; (3) Results; (4) Conclusions. The abstract should be an objective representation of the article. According to the reviewer, the abstract requires a small adjustment to the requirements.

2.       Introduction. The introduction section does not include the composition and content of individual sections of the article, which is usually the case in the last sentences of this section. This description of the content of the article is used in MDPI publications.

3.       Paragraphs 2.1.2. – 2.1.6. Website paths should be points in references.

4.       Figures 1, 2, 3, 4, 11, 13. The title figures are too long. The use of explanations should be included in the text with reference to the appropriate figure.

5.       Table 1. The title of Table 1 is too long. The use of explanations should be included in the text with reference to the table.

In the article, the Authors have used 45 items of references. The vast majority of references are contemporary items.

According to the reviewer, this article requires a minor correction at the points indicated above. In my review, I do not include more comments other than those presented in the review form.

Author Response

Author's Reply to the Review Report (Reviewer 1):

We the co-authors are very thankful for your comments on our manuscript "Oceanic Responses to 2021 Winter Storm Uri in the Gulf of Mexico from In Situ and Satellite Observations". Please find the detailed reply to your comments as follows:

Dear Editor,

The article Oceanic Responses to 2021 Winter Storm Uri in the Gulf of Mexico from In Situ and Satellite Observations is an original work.

The Authors described in Abstract the aim of their research in the words: … Our study demonstrates the utility of publicly available datasets for studying the impact of winter storms on the surface ocean.

The reviewer presents a general remark to the article, which is its 31-page volume. The above comment should be considered by the Editor and in this matter, I leave the decision to the Editor and the accepted practices in the Publishing House.

The review focuses on the formal side of the article and does not engage in polemics and discussions on the considerations adopted by the Authors because it determines the originality of the issue in the article. Considering the proposed solutions I accept it with appreciation.

The following observation require to draw attention and response from the Authors:

1. Abstract. According to the example pattern of writing MDPI articles, abstracts should give a pertinent overview of the work. The following style of structured abstract should be use but without headings: (1) Background; (2) Methods; (3) Results; (4) Conclusions. The abstract should be an objective representation of the article. According to the reviewer, the abstract requires a small adjustment to the requirements.

Reply: We thank the reviewer for this comment, however, we feel that the abstract in the revised version does take care of the background on the winter storm event, information on data used, some of the major outcome of this study and a conclusion based on our analysis. Given the word limit of the abstract, it clearly highlights our major findings and the fact how in situ as well as satellite data is used to study the impact of the winter storm over the surface ocean only.  

 

2. The introduction section does not include the composition and content of individual sections of the article, which is usually the case in the last sentences of this section. This description of the content of the article is used in MDPI publications.

Reply: Following this suggestion, a description of the content of the article has been added at the end of the Introduction section. 

 

3. Paragraphs 2.1.2. – 2.1.6. Website paths should be points in references.

Reply: Thanks. Website paths have been moved to the Data Availability Statement section in the revision. 

 

4. Figures 1, 2, 3, 4, 11, 13. The title figures are too long. The use of explanations should be included in the text with reference to the appropriate figure.

Reply: The figure captions of above-mentioned figures have been shortened to only include necessary description of the figures. Any explanations of figure usage have been moved into the text. 

 

5. Table 1. The title of Table 1 is too long. The use of explanations should be included in the text with reference to the table.

Reply: The title of Table 1 has been shortened by moving explanations into the text. 

 

In the article, the Authors have used 45 items of references. The vast majority of references are contemporary items. According to the reviewer, this article requires a minor correction at the points indicated above. In my review, I do not include more comments other than those presented in the review form.

Reply: We thank the reviewers for this observation. Our reference list does have more papers which are relatively contemporary, along with some references that go back to 1941, 1951, 1973 (when some of the earlier events of fish death due to cold on the Texas Coast are reported). Most of the publications are during the past 2 decades when these studies have been more reported.

Reviewer 2 Report (New Reviewer)

Summary:

 

The authors present a well-written, detailed description of the February 2021 winter storm that affected much of Texas and the western GoM. Their choice of datasets, however, should be improved and the organization of the paper is often lacking. Additional writing inconsistencies make the paper feel somewhat disjointed. The requested changes should be straightforward, but due to their magnitude I am recommending major revisions.

 

Comments:

 

-       Winter storms are not named by the NWS or WMO, and this is something the Weather Channel started doing in recent years. Only tropical storms/cyclones have names. In no way should this storm be referred to in a scientific publication by a name assigned to it by the Weather Channel arbitrarily.

-       The introduction contains a great deal of useful information and added context for the storm being analyzed, but it jumps around. For example, a nice segue from the atmospheric description to the potential oceanic effects is immediately followed by a discussion of infrastructure failures in Texas. The way this section bounces around is quite jarring. Section should be restructured for better flow.

-       It seems curious that despite focusing on the oceanic response to an atmospheric event, there is no real time given to the actual storm itself, with only one precipitation figure. It would help, perhaps in the introduction, to provide some atmospheric figures, such as surface pressure and 500 hPa pressure, to better demonstrate the magnitude of the storm and what the atmosphere was doing at the time.

-       I understand that OISST is a NOAA NCEI product, but it is not the highest quality SST product and has degraded over time. The authors should consider using Geo-Polar SSTs, which are available from NOAA CoastWatch and are also higher resolution.

-       Section 3.2.1 (and possibly other places): the plural of “fish” is still “fish”

-       Figure 4 (and heat budget): How would using a different SST dataset impact these results? While I understand the statistical significance found here and the physical mechanisms behind it, I do worry that using a dataset (OISST) that has been shown to have deterioration in recent years would alter this.

-       Is there a specific reason that ERA5 precipitation was used instead of satellite precipitation?

-       Abbreviation of MLD is inconsistent. It is frequently spelled out as mixed layer depth and interchanged with MLD in text. By contrast, the mixed layer is only abbreviated once in text and then spelled out afterward. All abbreviations must be consistent and used consistently. There is no point in abbreviating something and then not using the abbreviation.

-       Figure caption formatting is inconsistent.

-       Neither northwest nor southwest should be hyphenated

-       Degree symbols are often not correct (they’re in the middle of the line instead of being superscript)

Author Response

Author's Reply to the Review Report (Reviewer 2)

The authors present a well-written, detailed description of the February 2021 winter storm that affected much of Texas and the western GoM. Their choice of datasets, however, should be improved and the organization of the paper is often lacking. Additional writing inconsistencies make the paper feel somewhat disjointed. The requested changes should be straightforward, but due to their magnitude I am recommending major revisions.

 

We thank the reviewer for the comments. Please find our responses in detail herewith.

 

Comments:

1. Winter storms are not named by the NWS or WMO, and this is something the Weather Channel started doing in recent years. Only tropical storms/cyclones have names. In no way should this storm be referred to in a scientific publication by a name assigned to it by the Weather Channel arbitrarily.

Reply: “Winter Storm Uri” has been used in numerous scientific publications based on a quick google scholar search of the keyword “winter storm Uri”. We understand Uri was not named by the NWS or WMO, but it has been widely used in scientific publications due to the strength and damages caused by the storm. Other names that has been associated with this storm were valentine’s week winter outbreak (https://www.weather.gov/hgx/2021ValentineStorm), Northwest, Central, Eastern Winter Storm and Cold Wave (https://www.ncei.noaa.gov/access/billions/events/US/2021). However, winter storm Uri has been more popular not only among the science community, but also in the government organizations related to public information (https://www.fcc.gov/uri, https://www.ferc.gov/news-events/news/final-report-february-2021-freeze-underscores-winterization-recommendations). The decision to pick this name was purely based on the idea that this paper will provide more information to the public and more so to the decision makers who can use this information to understand such events. 

2. The introduction contains a great deal of useful information and added context for the storm being analyzed, but it jumps around. For example, a nice segue from the atmospheric description to the potential oceanic effects is immediately followed by a discussion of infrastructure failures in Texas. The way this section bounces around is quite jarring. Section should be restructured for better flow.

Reply: We thank the reviewer for this observation. In this context we revised the text in the introduction section and made sure the narrative has a better flow. 

3. It seems curious that despite focusing on the oceanic response to an atmospheric event, there is no real time given to the actual storm itself, with only one precipitation figure. It would help, perhaps in the introduction, to provide some atmospheric figures, such as surface pressure and 500 hPa pressure, to better demonstrate the magnitude of the storm and what the atmosphere was doing at the time.

Reply: Dear Reviewer, thank you for this suggestion. However, the atmospheric processes have been well described in published resources and we included references in the introduction if users would like to know more about the atmospheric processes. The focus of this paper is on the effect of the winter storm over oceans and how the surface ocean reacted to such a fast moving cold front. Therefore we do not feel it is necessary to include atmospheric figures, which is out of scope of this paper. We do have a paragraph in the Introduction to briefly describe the atmospheric processes during Uri.  Just to give an example of the overview on the atmospheric conditions we have added the following url: https://www.weather.gov/fwd/Feb-2021-WinterEvent in the introduction which has Weather Prediction Center’s surface and 500 hPa atmospheric conditions during the passage of the winter storm of 2021, which gives a quick link for readers who wants detailed atmospheric processes during Uri.  

4. I understand that OISST is a NOAA NCEI product, but it is not the highest quality SST product and has degraded over time. The authors should consider using Geo-Polar SSTs, which are available from NOAA CoastWatch and are also higher resolution.

Reply: While we acknowledge that there are various SST products available, it is important to note that the choice of dataset in our study was made with careful consideration and we  think the quality and resolution of OISST is sufficient enough to quantify the SST change during Uri. OISST is a widely used and reliable dataset in the scientific community. It is produced by NOAA NCEI, a reputable source for climate and oceanographic data. While no dataset is perfect, OISST has proven to be a robust resource for numerous scientific investigations. Moreover, it is worth noting that different SST products have their own strengths and limitations, and there is no single dataset that can fulfill all research requirements. Studies of Huang et al. (2021 and 2023) indicated that the performance of Geo-Polar Blended (GPB) and OISST is very close among other SST products.

Huang, B., X. Yin, J. A. Carton, L. Chen, G. Graham, C. Liu, T. Smith, H.-M. Zhang, 2023: Understanding Differences in Sea Surface Temperature Intercomparisons. JTECH, 40, 455-473, DOI 10.1175/JTECH-D-22-0081.1.

Huang, B., C. Liu, E. Freeman, G., Graham, T. Smith, and H.-M. Zhang, 2021: Assessment and Intercomparison of NOAA Daily Optimum Interpolation Sea Surface Temperature (DOISST) Version 2.1. J. Climate, 34, 7421-7441, https://doi.org/10.1175/JCLI-D-21-0001.s1.

5. Section 3.2.1 (and possibly other places): the plural of “fish” is still “fish”

Reply: Following your suggestion, we changed the plural of fish to fish in the revision. We would like to point out that fishes can be used when referring to more than one species. For example, the word “fishes” was used in the title of reference [8-10]. 

 

6. Figure 4 (and heat budget): How would using a different SST dataset impact these results? While I understand the statistical significance found here and the physical mechanisms behind it, I do worry that using a dataset (OISST) that has been shown to have deterioration in recent years would alter this.

Reply: We do not think using a different SST dataset will impact our results. Because the average SST decreased approximately 1.0 °C during Uri, which is much much larger than the standard error of the OISST dataset. Moreover, the heat budget calculation is a rough estimate to help us understand the role of surface heat flux in cooling. Small errors/uncertainties in SST won’t alter our conclusions considering the large SST change during the whole process. 

7. Is there a specific reason that ERA5 precipitation was used instead of satellite precipitation?

Reply:There is no specific reason to use ERA5 precipitation data instead of satellite based data. We just wanted to use data that is gap-free and has good resolution.

8. Abbreviation of MLD is inconsistent. It is frequently spelled out as mixed layer depth and interchanged with MLD in text. By contrast, the mixed layer is only abbreviated once in text and then spelled out afterward. All abbreviations must be consistent and used consistently. There is no point in abbreviating something and then not using the abbreviation.

Reply: Thanks for pointing this out. ML and MLD are now consistently used in the revision. 

9. Figure caption formatting is inconsistent.

Reply: All figure captions have now been standardized to follow a consistent format. We appreciate your careful review of our work.

10. Neither northwest nor southwest should be hyphenated

Reply: Hyphen has been removed for northwest and southwest. 

11. Degree symbols are often not correct (they’re in the middle of the line instead of being superscript)

Reply: Thanks. This has been fixed in the revision.

Reviewer 3 Report (New Reviewer)

The study examines oceanic responses to 2021 winter storm Uri in the Gulf of Mexico from In situ and satellite observations. The results reveal that net surface heat loss plays a primary role in the upper ocean cooling during Uri and can explain more than 50% of the cooling. Changes in salinity and Chlorophyll a could also be observed. This study demonstrates the utility of publicly-available datasets for studying the impact of winter storms on the surface ocean. The results in this study are generally reasonable. Some comments on the present manuscript are as follows.

 1. Line 25-26: Convective mixing due to surface cooling and turbulent mixing induced by enhanced wind speeds significantly increase the surface mixed layer. For convective mixing and turbulent mixing, which one is more important? If the turbulent mixing is more important, it should be mentioned first.

 2. Line 194: (accesses in June 2022). It is better to introduce these data information in the "Data Availability Statement" section.

 3. Table 1: The table format is not a three-line table.

 4. Line 272-273: The position of the formula number label is not aligned.

 5. Figure 8: There is no need to add black borders on the periphery of each sub-figures.

 6. Line 840: The long term trend between 1982 and 2021. This trend may not be totally due to global warming. The multi-decadal variations may also contribute to the decadal trend. Interdecadal variation also needs to be considered.

  7. The new scientific contributions in this research field need to be further highlighted.

 

 

Minor editing of English language required.

Author Response

Author's Reply to the Review Report (Reviewer 3):

We thank the reviewer for his comments following are our detailed reply to each comments.

 

The study examines oceanic responses to 2021 winter storm Uri in the Gulf of Mexico from In situ and satellite observations. The results reveal that net surface heat loss plays a primary role in the upper ocean cooling during Uri and can explain more than 50% of the cooling. Changes in salinity and Chlorophyll a could also be observed. This study demonstrates the utility of publicly-available datasets for studying the impact of winter storms on the surface ocean. The results in this study are generally reasonable. Some comments on the present manuscript are as follows.

1. Line 25-26: Convective mixing due to surface cooling and turbulent mixing induced by enhanced wind speeds significantly increase the surface mixed layer. For convective mixing and turbulent mixing, which one is more important? If the turbulent mixing is more important, it should be mentioned first.

Reply: Based on the heat budget analysis in the Discussion section, convective mixing induced by surface heat loss could cause at least 50% of the cooling in the mixed layer. Convective mixing should play a more important role than turbulent mixing. We prefer to put convective mixing before turbulent mixing. 

2. Line 194: (accesses in June 2022). It is better to introduce these data information in the "Data Availability Statement" section.

Reply: All the website links and dates of last accessed statements have been moved to the “Data Availability Statement” section in the revision.  

 

3. Table 1: The table format is not a three-line table.

Reply: Table 1 is a complicated table. A three-line table may cause misunderstanding if there is no line separation between stations. However, if the current format of Table 1 needs to be changed for the final publication, we will work with “MDPI Remote Sensing” to make sure Table 1 satisfies the publication requirements. 

4. Line 272-273: The position of the formula number label is not aligned.

Reply: We aligned up the formula number label in the revision. 

5. Figure 8: There is no need to add black borders on the periphery of each sub-figures.

Reply: Thank you for that suggestion, we made sure those black borders are not there in the final version.

6. Line 840: The long term trend between 1982 and 2021. This trend may not be totally due to global warming. The multi-decadal variations may also contribute to the decadal trend. Interdecadal variation also needs to be considered.

Reply: Thanks. The reviewer raised a valid point. We modified the text in the revision and added the following sentence in Section 4.3: “The detrending process removes a linear trend in SST to make the data collected in 2021 comparable to those during historical winter storm events. The trend in SST is mostly due to global warming [18, 27], but multi-decadal variations might also contribute to the long-term trend.”. Keep in mind, the purpose of detrend here is to make the cold spells during Uri in 2021 comparable to those during other historical winter storm events, not to examine the causes of warming.  In fact, the causes of the trend in SST are not important to our study. Nonetheless, comparison of the linear warming rate estimated in this study (Figure 4e) with those in other published papers (e.g. Müller-Karger et al. 2015; Li et al. 2022; Wang et al. 2023), indicates the long-term trend in SST should be mainly due to regional warming. Multi-decadal variations might have some contributions, but should be very limited. 

7. The new scientific contributions in this research field need to be further highlighted.

Reply: The premise that there has not been any study on impact over the ocean during such a winter storm event, led to this paper. This has been highlighted in the Introduction section.

Round 2

Reviewer 2 Report (New Reviewer)

The authors have addressed the bulk of my previous concerns with the manuscript with the exception of the issue of winter storm naming. Naming winter storms is not a convention adopted by either the NWS or WMO, and while it may be used in other scientific publications and colloquially, that does not make it good science. Given that the funding for this research is from NOAA, it feels a great deal like one branch of NOAA contradicting another branch in regards to naming winter storms. Further, the very fact that it has other names used suggests that it should not be given a colloquial one in addition to the others. It is fine to acknowledge that this storm is often referred to as "Winter Storm Uri" among other things, but that should not be what it is principally referred to in a NOAA-funded scientific publication, when the NWS does not name winter storms. Mid-latitude cyclones can reform multiple times, which is one of the many reasons that they are not named and most meteorologists balk at the idea. 

Author Response

Dear Reviewer we appreciate your concern related to the usage of "Winter Storm Uri". Therefore we have replaced that name through the text with more generalized name using information from the different NOAA reports. We call the storm by "Winter Storm Outbreak of February 2021 (WSO21)", and used the acronym WSO21 through out the text where Uri was used. We do mention at one place (Page 2 , L47-48) that this storm is also commonly referred to as "Winter Storm Uri" as per your suggestion. I hope this addresses the concern you have related to the naming of the storm.

Thank you for your comments and suggestions, that helped us improve the paper.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript by Wang et al. analyzed the various oceanic responses during a quite strong winter storm occurred in the Gulf of Mexico. However, I feel sorry to suggest that the current version of this manuscript is not suitable to be considered publishing on Remote Sensing. The biggest problem is that this study just simply showed the time evolution characteristics of various variables during this storm process, leading to a relatively poor science of this study. In other words, this study might have quite little implication for the scientific community. During this winter storm, the authors have collected a lot of valuable in situ observational data, which well recorded the impact of the storm. I would like to encourage the authors to find a more specific scientific question and more deeply dig the value of those data.

Reviewer 2 Report

This paper analyzes the ocean response to Winter Storm Uri in the Gulf of Mexico using a variety of datasets (in situ observations , satellite products and reanalysis data). I would like to express my respect for the attempt to present a scientific view by focusing on a case with social impacts.

On the other hand, I do not understand what the paper is trying to argue. Before asking to the authors what the new findings are, I am strongly concerned about the logic of the paper and the lack of scientific knowledge of the authors regarding the interpretation of oceanic variability. While I recommend that this paper be rejected for publication in the current form, new findings could be obtained if the analysis is conducted with a proper philosophy. The followings are some of the issues I have noticed. I hope they will be helpful for future research.

1. There is no information regarding Winter Storm Uri. The authors should show a brief introduction of this storm using weather maps and satellite images in each phase of Uri. I heard that tornadoes were actually observed during Uri. Readers may be interested in whether the tornadoes occurred over the ocean, resulting in the strong oceanic response.

2. I strongly doubt the quality of CYGNSS latent and sensible heat fluxes datasets. The authors should confirm whether the datasets are consistent with the fluxes calculated from the NBSv2 wind products. Latent and sensible heat fluxes are important in this paper because they are related to convective mixing as well as the reduction in sea surface temperature and the increase in sea surface salinity.

3. The difference between wind-curl-induced upwelling and coastal upwelling should be clarified. For this purpose, a budget analysis for sea surface temperature should be conducted by adding ocean current data for the analysis.

4. The vertical profile of salinity in the Gulf of Mexico appears to be vertically uniform according to Figure 1. It is impossible to explain the increase or decrease only by turbulent mixing. The vertical distribution of chlorophyll should also be shown in this paper.

5. The locations of buoy stations were deflected west of Gulf of Mexico, whereas the analysis domain covered the entire Gulf of Mexico. So it is very difficult for readers to understand what areas of the Gulf of Mexico is focused on to investigate the oceanic response to Uri.

6. As for understanding the spatial changes in sea surface salinity, it is necessary to properly assess the extent to which (heavy) precipitation has occurred during Uri.  Runoff of river water is also important in coastal areas to affect sea surface salinity.

7. The English expressions are not consistent overall the paper, perhaps because a few authors wrote it.

Reviewer 3 Report

General comment:

The authors investigated the upper oceanic changes and its response to the passage of a winter storm (Uri, February 2021) in the Gulf of Mexico (GoM) using satellite and in situ observations. The oceanic changes/responses include the sea surface temperature (SST), sea surface height (SSH), sea surface salinity (SSS), surface heat fluxes, and the depth of mixed layers in the western area of GoM. The research topic is relevant and within the scope of the journal. The data and methods are clearly described and sufficient. The authors also have done an excellent job in describing the results based on the figures. The references are appropriate. Overall, the paper is well written. However, there are still some minor issues (see specific comments below) for the authors to resolve. Therefore, I recommend for minor revision.

 

 

Specific comment:

1. Figure 1. The fonts are too small and light.

2. If applicable, please change colors for the shadings and lines to help color-blind readers (e.g., red-green color-blind readers) to easily read these figures.

3. Table 1 appears blurred, please make it clearer.

4. Figure 4: Color for linear equation in panel (e) is not necessary. Black font is preferred.

5. Figure 8. Vector size is too small, make the wind direction is illegible. Enlarge the vector and provide vector length reference value for each sub-panel.

6. Figure 10, 11,12: The fonts for title and labels are too small and light. The font size for color bar is also small and not legible. Black is a preferred font color for color bars.

7. Some minor checks for languages are requested.