Spatial Accessibility Analysis of Emergency Shelters with a Consideration of Sea Level Rise in Northwest Florida

Round 1

Reviewer 1 Report

The paper may need to conduct further improvement. 

1. Please provide the paper structure end of Section 1.

2. In Section 1, there is not a clear research context and objective. 

3. Since it links up with climate change, I suggest the authors can review the trend of climate change via the scientific report. 

4. The "resilience" concept can be adopted in the study. 

5. Please provide the references to support your discussion and argument. 

6. In the conclusion section, the authors may need to add the academic and managerial implications, limitation and future research direction. 

The English language needs to make moderate editing. 

Author Response

Authors’ Responses to Reviewers’ Comments Paper ‘sustainability-2422124’

“Spatial Accessibility Analysis of Emergency Shelters with a Consideration of Sea Level Rise in Northwest Florida”

 

The authors appreciate the reviewers’ time and valuable comments. We responded to the individual points raised by the reviewers and those changes are described below in detail.

 

Reviewer 1

 

We thank the reviewer for his/her excellent comments.

 

The paper may need to conduct further improvement.

 

1. Please provide the paper structure at the end of Section 1.

Response: Thanks for the comment. As the reviewer suggested, arranging a summary of the research process at the end of the Introduction chapter could make it easier for readers to understand the article, so we added the following paragraph at the end of the Introduction:

 

The remainder of the paper is organized as follows. First, an extensive literature review is presented with a focus on the evolution of the floating catchment method’s use for accessibility index estimation. This is followed by the section on data collection and preparation for population, transportation network and evacuation routes, hurricane forecasting information, and spatial distribution and capacities of hurricane shelters. Afterwards, storm surge models are set up and simulated with incorporating additional sea level rise scenarios for Hurricane Michael. Based on these simulations, floating catchment area-based scenarios are created to study the accessibility of shelters. Finally, results obtained from these accessibility analyses were discussed with future work directions and limitations of the work.

 

2. In Section 1, there is not a clear research context and objective.

Response: We appreciate your feedback. The 4^th paragraph in Introduction has been improved as follows:

 

Regrettably, although a substantial amount of research works focused on the SA to facilities such as health care services [1]–[3], libraries [4], supermarkets [5], and special needs shelters [6], [7] using floating catchment area methods and gravity models, there is still a paucity of research in the field of SA in terms of studying the impact of SLR on the transportation accessibility of shelters in the event of hurricanes. Consequently, this study relies on the lessons learned from a historically unusually intensified hurricane, namely Hurricane Michael, and its forecasted data to generate scenarios in analyzing SA to hurricane shelters with SLR considerations. The next step is to integrate them with a floating catchment area-based Geographical Information Systems (GIS) methodology. In particular, our objective is to provide practical insight into assessing the effectiveness of emergency evacuations to shelters, in the context of transportation accessibility, by considering the impact of SLR and answering the following research questions:

1. How and to what extent does the SLR impact the accessibility of hurricane shelters based on a floating catchment area-based Geographical Information Systems (GIS) methodology?
2. Is there any statistically significant difference between results of the floating catchment area-based models while calculating the accessibility of these shelters?

 

3. Since it links up with climate change, I suggest the authors can review the trend of climate change via the scientific report.

Response: We appreciate this constructive suggestion that can bring out the maturity of the research topic more clearly and naturally. Just to clarify, this study considers one of the factors that has the greatest impact in the event of hurricanes: sea level rise and sea temperature increase caused by global warming. Therefore, brief climate change trends are used to elicit warming as a factor rather than how it is conducted in this paper. Of course, future research can further expand climate-related hurricane hazard modeling and related evacuation accessibility, which is added as a future work in the Conclusions. However, based on the reviewer’s suggestion, the following content is added to the 3^rd paragraph of the Introduction:

 

Emergency planning should also consider long-term factors related to climate change so that it can be more efficient. The climate is the significant element that forms and increases the frequency and strength of hurricanes or other related coastal hazards [8]. Strong links between Atlantic Sea surface temperature and tropical cyclone activity have been mentioned several times in earlier studies [9] – tracing as far back as the late 1800s. Therefore, the major climate change, in terms of global warming, plays a key role in worsening hurricanes. It lifts the sea surface temperature (speed up winds) as well as water elevation (worsen the inundation). Strong scientific evidence exists that global warming has been speeding up under the dominant influence of greenhouse gases, and studies warned of sea level rise (SLR) and disruptions in the water cycle such as droughts and floods [10]. Long-term factors like SLR, and warm sea temperature which are related to global warming, can be severe in highly populated coastal regions due to an increase in storm surge nonlinearly, which should be considered when evaluating potential future hurricane flood conditions [11].

 

4. The "resilience" concept can be adopted in the study.

Response: Thanks for this suggestion. The reviewer is correct in that resilience is extremely important for better and more efficient evacuation planning. This paper currently focuses on a spatial accessibility analysis integrated with SLR, which can definitely be part of a broader resilience-focused planning process. Resilience exploration encompasses forecasting, planning, and reducing disaster risks, and this paper can be an asset in planning and reducing hurricane impact on communities. Subsequent research could focus on determining the optimal placement and protection of power and transportation infrastructure during hurricanes [12]. Additionally, efforts can be made to enhance flexibility and adaptability to effectively address unforeseen and significant disruptions caused by such events. This information is added to the Introduction section.

 

5. Please provide the references to support your discussion and argument.

Response: We appreciate the suggestion. The manuscript has been edited and revised with proper references to increase the level of detail with regard to how issues of accuracy and appropriateness were dealt with in this work.

 

To begin with, the studied area in Northwest Florida is naturally at a low level with one medium-sized city and rural areas, indicating a diverse distribution of the population. Rural areas often have limited evacuation facilities and roadway access compared to urban areas, making it more difficult for residents in these remote areas to get to safety in a timely manner in the event of a hurricane. Additionally, the area’s susceptibility to these severe weather events, including hurricanes, exacerbates the need for hurricane shelters. Also, the frequency of hurricanes in the region is increasing as the ocean surface steadily rises due to global warming. This directly leads to the unpredictability of hurricane occurrences which would lead to uncertainty in the evacuation operations and accessibility of shelters. This makes it very difficult to make concrete discussions on the accuracy of the models. Ideally, the accuracy of the methods should be compared with “ground truth” data. Unfortunately, this data set is not available, so we provided a means of sensitivity analysis with multiple SLR levels and compared two methods in order to make sure of the applicability and appropriateness of the proposed methods. Much of the information reviewed was highly technical and procedural in nature, and continuously refining our approach is important for maintaining and augmenting its future utility. This information is added to the Conclusions section.

 

As mentioned in the conclusion, to enhance the accuracy and reliability of the findings, both E2SFCA and 3SFCA methods employed distance decay weights to evaluate the spatial accessibility of shelters. However, 3SFCA incorporated an additional selection weight that considered the appropriate population served by each shelter. In the case of a hurricane evacuation, people tend to choose the shelter that requires the least driving time. Thus, shelters located closer to urban centers tend to be more attractive and receive a higher number of victims. The selection weight in 3SFCA considers this factor and assigns a higher probability to those shelters that can be reached in the shortest driving time. Shelters located far away from population centroids can avoid overestimation of demand while reducing excess congestion so that people would not drive to them in real-world situations.

 

6. In the conclusion section, the authors may need to add the academic and managerial implications, limitation and future research direction.

Response: We appreciate these constructive comments. The relevant discussion is added to the Conclusions section regarding academic and managerial implications, limitations, and future work.

 

In the last paragraph of ‘5. Conclusions and Future Work’, we stated that the limitation of this research contains two aspects. Firstly, the SLR was individually added as the base water elevation for each storm surge simulation scenario, however in reality SLR would change the coastal boundary and make some previously existing land to be under water, which could lead to a totally different evacuation demand. Secondly, it is crucial to acknowledge that the accessibility index is just one of many measures of accessibility, and it may not always provide a comprehensive view of accessibility to emergency facilities. Although this paper focuses on driving time, the physical distance between two locations is frequently a crucial factor in accessibility measures. In addition, the mode of transportation used to travel between locations can significantly influence accessibility measures. For instance, accessibility for pedestrians should differ significantly compared to drivers. The quality and availability of transportation infrastructure, such as sidewalks for pedestrians and public transportation for low-mobility populations, is also critical to consider. Other socioeconomic factors such as income, education, and age can also influence accessibility, making it a multi-faceted concept that requires a multidimensional approach. As a result, a holistic view of accessibility should be taken into account when designing and implementing policies and interventions aimed at enhancing real-world accessibility.

Based on the discussion, future works, and research directions can potentially move towards 1) finding a dynamic SLR modeling method that accounts for the changing coastal land characteristics, 2) exploring alternative measures of accessibility such as distance, mode of transportation, and roadway reliance, and 3) investigating the influence of socioeconomic factors on SA to emergency facilities. Also, future research can further expand the proposed work toward climate-related hurricane hazard modeling, resilience-based approaches, and related evacuation accessibility. Some other possible suggestions for future evacuation preparations can be improving roadways by widening roads, elevating roadways, and improving better traffic flow management. Providing public transportation options during evacuation using vehicles such as buses can also help increase the accessibility for people with lower income levels, people living in rural areas, and other vulnerable populations who do not have their own cars. Also, future work may consider an application of other advanced floating catchment area methods or spatial-related accessibility analysis methods.

Author Response File: Author Response.pdf

Reviewer 2 Report

1-Amend/refine abstract. Abstract should be improved first explaining a problem and then explaining its proposed solution and benefits over existing strategies.

2- Introduction should be divided the into sub-sections (name each sub-section) like: 1) Background, 2) Literature review, 3) Research gap and motivation, 4) Challenges, 5) Contribution and 6) paper organization.

3- Quality of figures is not sufficient.

4- Literature review should be more strengthen.

5-  Would like to recommend to the authors making a deeper state-of-the-art review. This will help to remark the contribution, this will help to remark the contribution. "An improved equilibrium optimizer for optimal placement of photovoltaic systems in radial distribution power networks, Neural Computing and Applications"; "Optimal Distributed Photovoltaic Units Placement in Radial Distribution System Considering Harmonic Distortion Limitation., International Journal on Electrical Engineering & Informatics".

Extensive editing of English language required

Author Response

Authors’ Responses to Reviewers’ Comments Paper ‘sustainability-2422124’

“Spatial Accessibility Analysis of Emergency Shelters with a Consideration of Sea Level Rise in Northwest Florida”

 

The authors appreciate the reviewers’ time and valuable comments. We responded to the individual points raised by the reviewers and those changes are described below in detail.

 

Reviewer 2

We thank the reviewer for his/her excellent comments.

 

1-Amend/refine abstract. Abstract should be improved first explaining a problem and then explaining its proposed solution and benefits over existing strategies.

Response: We appreciate the good suggestion on abstract. As suggested, we highlighted the research gap in the first sentence of abstract and generated the previous research process before moving forwards to findings as color-marked below:

 

Hurricane-induced storm surge and flooding often lead to the closures of evacuation routes, which can be disruptive for the victims trying to leave the impacted region. This problem becomes even more challenging when we consider the impact of sea level rise that happens due to global warming and other climate-related factors. As such, hurricane-induced storm surge elevations would increase nonlinearly when sea level rise lifts, flooding access to highways and bridge entrances, thereby reducing accessibility for affected census block groups to evacuate to hurricane shelters during hurricane landfall. This happened with the Category 5 Hurricane Michael which swept the east coast of Northwest Florida with long-lasting damage and impact on local communities and infrastructure. In this paper, we propose an integrated methodology that utilizes both sea level rise scenario-informed storm surge simulations and floating catchment area models built in Geographical Information Systems (GIS). First, we set up sea level rise scenarios of 0, 0.5, 1, and 1.5 meters with a focus on Hurricane Michael’s impact that led to the development of storm surge models. Second, these storm surge simulation outputs are fed into ArcGIS and floating catchment area-based scenarios are created to study the accessibility of shelters. Findings indicate that rural areas lost accessibility faster than urban areas due to a variety of factors including shelter distributions, and roadway closures as spatial accessibility to shelters for offshore populations was rapidly diminishing. We also observed that as inundation level increases, urban census block groups that are closer to the shelters get extremely high accessibility scores through FCA calculations compared to the other block groups. Results of this study could guide and help revise existing strategies for designing emergency response plans and update resilience action policies.

 

2- Introduction should be divided the into sub-sections (name each sub-section) like: 1) Background, 2) Literature review, 3) Research gap and motivation, 4) Challenges, 5) Contribution and 6) paper organization.

Response: We appreciate this constructive suggestion. The Introduction section is divided into six different subsections as suggested by the reviewer.

 

3- Quality of figures is not sufficient.

Response: Thanks for this helpful comment, figures are reuploaded with quality improvements.

 

4- Literature review should be more strengthened. Would like to recommend to the authors making a deeper state-of-the-art review. This will help to remark the contribution, this will help to remark the contribution.

Response: Thanks for the suggestion. As suggested, we improved the literature review.

 

In the Introduction section, we firstly added additional climate change focused review:

 

Climate is the significant element that forms and increases the frequency and strength of hurricanes or other related coastal hazards [1]. Strong links between Atlantic Sea surface temperature and tropical cyclone activity have been mentioned several times in earlier studies [2] – tracing as far back as the late 1800s. Therefore, the major climate change, in terms of global warming, plays a key role in worsening hurricanes. It lifts the sea surface temperature (speed up winds) as well as water elevation (worsen the inundation). Strong scientific evidence exists that global warming has been speeding up under the dominant influence of greenhouse gases, and studies warned of sea level rise (SLR) and disruptions in the water cycle such as droughts and floods [3]. Long-term factors like SLR, warm sea temperature which are related to global warming, can be severe in highly populated coastal regions due to an increase in storm surge nonlinearly, which should be considered when evaluating potential future hurricane flood conditions [4].

 

Secondly, to clarify and show the value of applying two different methods in this paper, we introduced a more detailed review for both E2SFA and 3SFCA as shown below:

 

Section 2.1:

E2SFCA came out as early as 2009 [5] and it is a very powerful and popular tool in healthcare accessibility analysis. Many research papers have applied E2SFCA to measure accessibility in developing countries [6]. In the literature, 2SFCA had many adaptations such as Hierarchical 2SFCA (H2SFCA)[7], integrated a Variable Distance Decay Function with FCA [8], and Multi-Modal 2SFCA [9], [10]. However, many of these bring complexities such as longer computational time. Compared with other adapted 2SFCA models, E2SFCA is simpler and more applicable to the analyses of transportation networks and demographics. That is why it was selected to study the region selected. In addition, the E2SFCA method is very suitable for evaluating emergency accessibility during hurricane evacuations.

 

Section 2.2:

While the 3SFCA method itself is already an extension of the 2SFCA method, several researchers also developed further extensions and adaptations of it to further enhance the spatial analysis of healthcare access. One significant extension to the 3SFCA method includes Modified Huff 3SFCA (MH3SFCA) [11], which simulates distance attenuation effects and more realistically verifies the continuity of attenuation. Compared with the diversity of 2SFCA, 3SFCA still has high development potential because of its short computational time [12]. Although this study provides a comparison of the accessibility results of two methods on the accessibility of hurricane shelters, a follow-up research direction can be the further development of 3SFCA. This development can be performed in order to make the model more suitable for coastal rural areas like Northwest Florida.

 

Section 2.3:

Although 3SFCA was developed more recently than E2SFCA, both have been applied in a variety of accessibility research works with informative results. Based on the findings in the next section, 3SFCA is found to be more adaptable when the evacuation case requires demand separation. E2SFCA is relatively clarified for ‘global’ accessibility index observation, which provides a general assessment of accessibility that does not take demand variation and supply competition into consideration. While 3SFCA works perfectly when both demand and supply are influenced by travel costs, it also provides a more detailed and accurate assessment of accessibility.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper investigates Spatial Accessibility Analysis of Emergency Shelters with a 2 Consideration of Sea Level Rise in Northwest Florida. I have the following comments:

1. The proposed E2SFCA and 3SFCA methods should be compared with the current-state-of-the-art method.

2. The statistical signaficance of the results should be discussed to test how signficant the results.

3. The assumptions and factors that can affect the results should be discussed and what happen if these assumptions or factors changed.

4. The limitation of the proposed analysis methods should be discussed.

5. The accuracy of proposed methods should be discussed.

None

Author Response

 Authors’ Responses to Reviewers’ Comments Paper ‘sustainability-2422124’

“Spatial Accessibility Analysis of Emergency Shelters with a Consideration of Sea Level Rise in Northwest Florida”

 

The authors appreciate the reviewers’ time and valuable comments. We responded to the individual points raised by the reviewers and those changes are described below in detail.

 

Reviewer 3

The paper investigates Spatial Accessibility Analysis of Emergency Shelters with a 2 Consideration of Sea Level Rise in Northwest Florida. I have the following comments:

 

We thank the reviewer for his/her excellent comments.

 

1. The proposed E2SFCA and 3SFCA methods should be compared with the current-state-of-the-art method.

Response: We appreciate the constructive comment. To clarify, both E2SFCA and 3SFCA methods are quite up to date in spatial accessibility analysis, while 3SFCA is more contemporary than any two-step-based methods and is branched to more complex calculating methods. However, in order to provide more information on these methods and their relationship with others, we added the following discussion in the Literature Review section:

 

Section 2.1:

E2SFCA came out as early as 2009 [1] and it is a very powerful and popular tool in healthcare accessibility analysis. Many research papers have applied E2SFCA to measure accessibility in developing countries [2]. In the literature, 2SFCA had many adaptations such as Hierarchical 2SFCA (H2SFCA)[3], integrated a Variable Distance Decay Function with FCA [4], and Multi-Modal 2SFCA [5], [6]. However, many of these bring complexities such as longer computational time. Compared with other adapted 2SFCA models, E2SFCA is simpler and more applicable to the analyses of transportation networks and demographics. That is why it was selected to study the region selected. In addition, the E2SFCA method is very suitable for evaluating emergency accessibility during hurricane evacuations.

 

Section 2.2:

While the 3SFCA method itself is already an extension of the 2SFCA method, several researchers also developed further extensions and adaptations of it to further enhance the spatial analysis of healthcare access. One significant extension to the 3SFCA method include Modified Huff 3SFCA (MH3SFCA) [7], which simulates distance attenuation effects and more realistically verifies the continuity of attenuation. Compared with the diversity of 2SFCA, 3SFCA still has high development potential because of its short computational time [8]. Although this study provides a comparison of the accessibility results of two methods on the accessibility of hurricane shelters, a follow-up research direction can be the further development of 3SFCA. This development can be performed in order to make the model more suitable for coastal rural areas like Northwest Florida.

 

Section 2.3:

Although 3SFCA was developed more recently than E2SFCA, both have been applied in a variety of accessibility research works with informative results. Based on the findings in the next section, 3SFCA is found to be more adaptable when the evacuation case requires demand separation. E2SFCA is relatively clarified for ‘global’ accessibility index observation, which provides a general assessment of accessibility that does not take demand variation and supply competition into consideration. While 3SFCA works perfectly when both demand and supply are influenced by travel cost, it also provides a more detailed and accurate assessment of accessibility.

 

Also, future work may consider an application of other advanced floating catchment area methods or spatial-related accessibility analysis methods.

 

2. The statistical significance of the results should be discussed to test how significant the results.

Response: Thanks for the constructive suggestion. Previously in our manuscript, we attempt to describe the significant drop of accessibility index of E2SFCA as well as 3SFCA based on histograms, mean, and median value of each evacuation scenario. The count of census block groups with Ai <0.03 increased with an unstable speed while SLR was lifted up linearly between E2SFCA scenarios. This is a chain reaction of the nonlinear spreading of inundation mentioned in previous literature. While in 3SFCA analysis, the number of census block groups with higher  in E2SFCA had an increasing trend. For instance, in Figure 3a, there were 4 block groups who had  higher than 0.2 whereas it increased to 14 block groups whose  values were higher than 0.2 in Figure 3e. However, the number of high  census block groups in 3SFCA seemed to be stable when SLR increased. Looking at histograms in Figure 4a and Figure 4e, the number of census block groups whose  distribution is shown at the end where largest value interval was staying as 1.

 

Additionally, we generated a separate section, 4.4. Comparison of results for detailed and specific statistical analysis. In order to determine whether the comparison between each related E2SFCA and 3SFCA accessibility score has a special distribution and thus apply an appropriate statistical method, the Kolmogorov–Smirnov (K-S) test was firstly used to determine whether the difference of two sets of results follow normal distribution or not [9]–[11].

None of any set of accessibility index results provided a normal cumulative distribution. In addition, p-values during K-S test were smaller than  among scenarios, providing another reason to reject normality. Note that base scenarios were related to original evacuations during blue sky days without SLR, while the other scenarios are either based on the inundation caused by Hurricane Michael at its observed strength or more severe inundation with additions of SLR. As such, the calculation results of the two methods have dived at the front end of the cumulative distribution. To present the differences of two sets of non-normally distributed results, a nonparametric statistic test, the Wilcoxon signed rank test was applied to conduct the required statistical analysis [12]–[14]. This test does not need to assume a specific distribution of the data and is suitable for nonnormal as well as skewed data, while it can observe the magnitude of the difference between variables. At the same time, the test has been known to perform well even with small sample sizes [15], suitable for the resulting data size of this study. For this research, the null and alternative hypotheses in this test were:

: The median of the accessibility score differences between two methods is zero;

: The median of the accessibility score differences between two methods is not zero.

As shown in Table 2, we obtained a quantitative assessment of the data differences with p-values listed, supporting the interpretation of our research findings and the derivation of conclusions. The observation was intriguing, as they indicated a substantial difference between the accessibility index simulations of E2SFCA and 3SFCA. For base scenarios, since there was no external influence due to an event like a hurricane, the existing accessibility of this area showed a certain similarity under the two sets of calculations. It is understandable because the evacuated area was fixed as well as the demand/locations (i.e., population/origins) are fixed, the shelters and transportation network were also not affected. However, once the effects of hurricanes and SLRs were present, the accessibility scores derived from the two methods showed significant differences.

 

Table 2. Wilcoxon Signed Rank Test for E2SFCA and 3SFCA Accessibility Index Results.

SLR (meters)	Block Groups (Total)	Block Groups (Nonzero AI)	z-Value	Signed Rank	p-Value
0	162	130	2.239	5221	0.025(.)
0.5	162	130	2.352	5117	0.019(.)
1	162	106	2.384	3592	0.017(.)
1.5	162	91	2.118	2683	0.034(.)
Base Scenario	162	162	1.630	7576	0.103()
Significance codes: 0 “***” 0.001 “**” 0.01 “*” 0.05 “.” 0.1 “ “ 1

 

3. The assumptions and factors that can affect the results should be discussed and what would happen if these assumptions or factors changed.

Response: We appreciate the reviewer’s suggestions. We have provided the relevant information in the revised manuscript. In section 3.2, the assumptions and potential impacted factors related to our research are listed as follows:

1) It was assumed that coastal boundary of impacted areas would not shrink sharply when SLR increased up to 1.5m, which is the maximum water level considered by our models. SLR could inundate shorelines and make previous residential places unavailable before hazards, which could change the evacuation demand (i.e., population to be evacuated) and locations of origins in the OD Matrix. Since this research had a specific focus on additional inundation brought by SLR, and 1.5m SLR only affected the coastal beach areas mostly, there was no significant difference of residential locations being inundated by SLR.

2) It was assumed that the only effect of SLR would be to increase the hurricane’s direct impact. Other climatic conditions, such as the stability of atmospheric pressure, may also play a role in the formation of hurricanes, but they are not the focus of this study. To visualize the challenges that SLR posed for hurricane evacuations, the model only assumed the water elevation changes during hurricane development using different scenarios. Ease of evacuation and accessibility changes are subject to this single impact of SLR.

3) Residents in the studied four counties were assumed to own vehicles or have access to vehicles so that they would choose to evacuate to hurricane shelters. Travel costs and catchment thresholds were determined using travel time by a motor vehicle. Other travel modes such as transit, cycling and walking were out of scope in this study.

4) It was assumed that the roadway closures were due to flooding to make model’s focus directly on the impact of SLR. Strong wind could knock down trees, traffic poles and other similar structures above the ground, causing roadway disruptions and other related shortages; however, in this research, only inundation was considered as the major factor in SLR scenarios causing lower accessibility levels. It is worth mentioning that if wind damage were added, the affected area would be larger, and the accessibility will be more unpredictable and unquantifiable. This is a very relevant area of future work.

To summarize, the current research focused on examining accessibility scores within the context of the study area, without considering other potential ramifications of rising sea levels. It is important to note that increasing SLR has the potential to significantly alter coastal regions by causing shoreline inundation and land boundary flooding under the water. As such, these unconcerned land boundary changes due to water inundation may have profound implications for the accessibility of various locations along the coast. Given the dynamic nature of coastal environments, it is expected that the number of census block groups with nonzero accessibility scores would experience a continuous and nonlinear decrease as sea levels rise. This is due to the encroachment of seawater onto previously accessible areas, leading to reduced connectivity and increased spatial barriers.

 

4. The limitation of the proposed analysis methods should be discussed.

Response: Thanks for the suggestion. Limitations of this research have been discussed in the Conclusions section of the revised manuscript. They mainly contain two aspects. Firstly, the SLR was individually added as the base water elevation for each storm surge simulation scenario; however, SLR would actually change the coastal boundary and submerge some of the coastal land in the long run. This could lead to a totally different evacuation demand as well as roadway infrastructure. Secondly, it is crucial to acknowledge that the accessibility index is just one of many measures of accessibility, and it may not always provide a comprehensive view of accessibility to emergency facilities. Although this paper focuses on driving time, the physical distance between two locations is frequently a crucial factor in accessibility measures. In addition, the mode of transportation used to travel between locations can significantly influence accessibility measures. For instance, accessibility for pedestrians should differ significantly compared to drivers. The quality and availability of transportation infrastructure, such as sidewalks for pedestrians and public transportation for low-mobility populations, is also critical to consider. Other socioeconomic factors such as income, education, and age can also influence accessibility, making it a multifaceted concept that requires a multidimensional approach. As a result, a holistic view of accessibility should be taken into account when designing and implementing policies and interventions aimed at enhancing real-world accessibility.

 

5. The accuracy of proposed methods should be discussed.

Response: We appreciate the suggestion. The manuscript has been edited and revised to increase the level of detail with regard to how issues of accuracy and appropriateness were dealt with in this work.

 

To begin with, the studied area in Northwest Florida is naturally at a low level with one medium-size city and rural areas, indicating a diverse distribution of the population. Rural areas often have limited evacuation facilities and roadway access compared to urban areas, making it more difficult for residents in these remote areas to get to safety in a timely manner in the event of a hurricane. Additionally, the area’s susceptibility to these severe weather events, including hurricanes, exacerbates the need for hurricane shelters. Also, the frequency of hurricanes in the region is increasing as the ocean surface steadily rises due to global warming. This directly leads to the unpredictability of hurricane occurrences which would lead to uncertainty in the evacuation operations and accessibility of shelters. This makes it very difficult to make concrete discussions on the accuracy of the models. Ideally, the accuracy of the methods should be compared with “ground truth” data. Unfortunately, this data set is not available, so we provided a means of sensitivity analysis with multiple SLR levels and compared two methods in order to make sure of the applicability and appropriateness of the proposed methods. Much of the information reviewed was highly technical and procedural in nature, and continuously refining our approach is important for maintaining and augmenting its future utility. This information is added to the Conclusions section.

 

As mentioned in conclusion, to enhance the accuracy and reliability of the findings, both E2SFCA and 3SFCA methods employed distance decay weights to evaluate the spatial accessibility of shelters. However, 3SFCA incorporated an additional selection weight that considered the appropriate population served by each shelter. In the case of a hurricane evacuation, people tend to choose the shelter that requires the least driving time. Thus, shelters located closer to urban centers tend to be more attractive and receive a higher number of victims. The selection weight in 3SFCA considers this factor and assigns a higher probability to those shelters that can be reached in the shortest driving time. Shelters located far away from population centroids can avoid overestimation of demand, while reducing excess congestion so that people would not drive to them in real world situations.

 

Added References

 

[1]   W. Luo and Y. Qi, “An Enhanced Two-Step Floating Catchment Area (E2SFCA) Method for Measuring Spatial Accessibility to Primary Care Physicians,” Health & place, vol. 15, pp. 1100–7, Jul. 2009, doi: 10.1016/j.healthplace.2009.06.002.

[2]  J. A. Tali, M. Nazir, and M. ul Shafiq, “Enhanced Two-Step Floating Catchment Area (E2SFCA) Method for Measuring Spatial Accessibility to Primary Healthcare in HD Kote, Mysore (India),” in Towards Sustainable Natural Resources: Monitoring and Managing Ecosystem Biodiversity, M. Rani, B. S. Chaudhary, S. Jamal, and P. Kumar, Eds., Cham: Springer International Publishing, 2022, pp. 255–273. doi: 10.1007/978-3-031-06443-2_14.

[3]   Z. Tao, Y. Cheng, and J. Liu, “Hierarchical two-step floating catchment area (2SFCA) method: measuring the spatial accessibility to hierarchical healthcare facilities in Shenzhen, China,” International Journal for Equity in Health, vol. 19, no. 1, p. 164, Sep. 2020, doi: 10.1186/s12939-020-01280-7.

[4]   J. Bauer and D. A. Groneberg, “Measuring Spatial Accessibility of Health Care Providers – Introduction of a Variable Distance Decay Function within the Floating Catchment Area (FCA) Method,” PLOS ONE, vol. 11, no. 7, p. e0159148, Jul. 2016, doi: 10.1371/journal.pone.0159148.

[5]   M. Langford, G. Higgs, and R. Fry, “Multi-modal two-step floating catchment area analysis of primary health care accessibility,” Health Place, vol. 38, pp. 70–81, Mar. 2016, doi: 10.1016/j.healthplace.2015.11.007.

[6]   Z. Tao, Z. Yao, H. Kong, F. Duan, and G. Li, “Spatial Accessibility to Healthcare Services in Shenzhen, China: Improving the Multi-Modal Two-Step Floating Catchment Area Method by Estimating Travel Time Via Online Map APIs,” BMC Health Services Research, vol. 18, 2018, doi: 10.1186/s12913-018-3132-8.

[7]   R. Jörg and L. Haldimann, “MHV3SFCA: A new measure to capture the spatial accessibility of health care systems,” Health & Place, vol. 79, p. 102974, Jan. 2023, doi: 10.1016/j.healthplace.2023.102974.

[8]   A. Páez, C. Higgins, and S. Vivona, “Demand and level of service inflation in Floating Catchment Area (FCA) methods,” PLOS ONE, vol. 14, p. e0218773, Jun. 2019, doi: 10.1371/journal.pone.0218773.

[9]   F. J. Massey, “The Kolmogorov-Smirnov Test for Goodness of Fit,” Journal of the American Statistical Association, vol. 46, no. 253, pp. 68–78, Mar. 1951, doi: 10.1080/01621459.1951.10500769.

[10] C. Whitnall, E. Oswald, and L. Mather, “An Exploration of the Kolmogorov-Smirnov Test as a Competitor to Mutual Information Analysis,” in Smart Card Research and Advanced Applications, E. Prouff, Ed., in Lecture Notes in Computer Science. Berlin, Heidelberg: Springer, 2011, pp. 234–251. doi: 10.1007/978-3-642-27257-8_15.

[11] R. A. Olea and V. Pawlowsky-Glahn, “Kolmogorov–Smirnov test for spatially correlated data,” Stoch Environ Res Risk Assess, vol. 23, no. 6, pp. 749–757, Aug. 2009, doi: 10.1007/s00477-008-0255-1.

[12] S. W. Scheff, “Chapter 8 - Nonparametric Statistics,” in Fundamental Statistical Principles for the Neurobiologist, S. W. Scheff, Ed., Academic Press, 2016, pp. 157–182. doi: 10.1016/B978-0-12-804753-8.00008-7.

[13] R. H. Riffenburgh, “Chapter 16 - Tests on Ranked Data,” in Statistics in Medicine (Second Edition), R. H. Riffenburgh, Ed., Burlington: Academic Press, 2006, pp. 281–303. doi: 10.1016/B978-012088770-5/50056-3.

[14] A. Vierra, A. Razzaq, and A. Andreadis, “Chapter 27 - Continuous variable analyses: t-test, Mann–Whitney U, Wilcoxon sign rank,” in Translational Surgery, A. E. M. Eltorai, J. A. Bakal, P. C. Newell, and A. J. Osband, Eds., in Handbook for Designing and Conducting Clinical and Translational Research. Academic Press, 2023, pp. 165–170. doi: 10.1016/B978-0-323-90300-4.00045-8.

[15] A. K. Dwivedi, I. Mallawaarachchi, and L. A. Alvarado, “Analysis of small sample size studies using nonparametric bootstrap test with pooled resampling method,” Statistics in Medicine, vol. 36, no. 14, pp. 2187–2205, 2017, doi: 10.1002/sim.7263.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The revised version is fine for me. 

Author Response

Authors’ Responses to Reviewers’ Comments Paper ‘sustainability-2422124’

“Spatial Accessibility Analysis of Emergency Shelters with a Consideration of Sea Level Rise in Northwest Florida”

 

The authors again sincerely appreciate the reviewers’ time and valuable comments. With minor revisions to the paper, we responded individually and related minor changes are included below in detail.

 

Reviewer 1: The revised version is fine for me

Response: We thank the reviewer for his/her excellent comments and help during this peer review section. His/her comments contribute greatly to improving this manuscript and we appreciate it.

Reviewer 2 Report

This paper namely "Coordination control of active crowbar for Doubly fed induction generator, 2014 International Symposium on Fundamentals of Electrical Engineering (ISFEE)" will help to remark your contribution related to  Emergency Technology.

Minor editing of English language required

Author Response

Authors’ Responses to Reviewers’ Comments Paper ‘sustainability-2422124’

“Spatial Accessibility Analysis of Emergency Shelters with a Consideration of Sea Level Rise in Northwest Florida”

 

The authors again sincerely appreciate the reviewers’ time and valuable comments. With minor revisions to the paper, we responded individually and related minor changes are included below in detail.

Reviewer 2: This paper namely "Coordination control of active crowbar for Doubly fed induction generator, 2014 International Symposium on Fundamentals of Electrical Engineering (ISFEE)" will help to remark your contribution related to Emergency Technology.

Response: We thank the reviewer for his/her suggestions. For emergency technology discussion, we included this paper by mentioning that: the investigation of emergency response methodologies pertaining to hurricane evacuations, including power supply stabilization and security [49], merits scholarly examination. Given the prevailing conditions of pronounced climate change, it becomes imperative to deliberate conscientiously on not only the enhancement of evacuation accessibility and personal safety assurance but also on the resilience of infrastructural technology in effectively addressing more severe adversities that lie ahead.

 

[49]   G. N. Sava, M. Q. Duong, S. Leva, M. Mussetta, S. Costinas, and N. Golovanov, “Coordination control of active crowbar for doubly fed induction generators,” in 2014 International Symposium on Fundamentals of Electrical Engineering (ISFEE), Nov. 2014, pp. 1–5. doi: 10.1109/ISFEE.2014.7050541.

 

Reviewer 3 Report

The authors considered my comments

Author Response

Authors’ Responses to Reviewers’ Comments Paper ‘sustainability-2422124’

“Spatial Accessibility Analysis of Emergency Shelters with a Consideration of Sea Level Rise in Northwest Florida”

 

The authors again sincerely appreciate the reviewers’ time and valuable comments. With minor revisions to the paper, we responded individually and related minor changes are included below in detail.

 

Reviewer 3: The authors considered my comments.

Response: We thank the reviewer for his/her excellent comments and help during this peer review section. His/her comments contribute greatly to improving this manuscript and we really appreciate it.