Innovative Remote Sensing Identification of Cyanobacterial Blooms Inspired from Pseudo Water Color
, Yuanyuan Jing 1,2, Yuchao Zhang 1,3,*, Lai Lai 1,2, Zhaomin Liu 1,2 and Qiduo Yang 1,2Round 1
Reviewer 1 Report
The spectral techniques remind me of the work of J.W. Boardman and F.A. Kruse.
In part, Boardman and Kruse built their work upon a major innovator of spectral remote sensing work, A.F.H. Goetz, using imaging spectroscopy . Boardman and Kruse often reference Goetz such as, Imaging Spectroscopy for Earth Remote Sensing, 1985. Science 228, 4704: 1147-1153.
Application of these researchers was originally geology, but the technique they developed was incorporated into ENVI (which you reference).
Science is built upon previous colleagues work.
1 - I feel you should consider referencing the two pioneers for your work, Boardman and Kruse. They have used their spectral algorithms for numerous applications using many remote sensing systems.
2 - My other suggestion for your very good paper is to define acronyms for readers not familiar with the subject.
Author Response
Reviewer 1#:
The spectral techniques remind me of the work of J.W. Boardman and F.A. Kruse.
In part, Boardman and Kruse built their work upon a major innovator of spectral remote sensing work, A.F.H. Goetz, using imaging spectroscopy . Boardman and Kruse often reference Goetz such as, Imaging Spectroscopy for Earth Remote Sensing, 1985. Science 228, 4704: 1147-1153.
Application of these researchers was originally geology, but the technique they developed was incorporated into ENVI (which you reference).
Science is built upon previous colleagues work.
1 - I feel you should consider referencing the two pioneers for your work, Boardman and Kruse. They have used their spectral algorithms for numerous applications using many remote sensing systems.
Response: Thanks for this comment. We have carefully read the literature of J.W. Boardman and F.A. Kruse. These two pioneers have made great achievements in imaging spectral applications and remote sensing algorithms (Boardman 1998; Kruse et al. 2003; Kruse et al. 2000), especially in pixel unmixing (Boardman 1993, 1998; Boardman et al. 1995). In fact, our previous work on identifying cyanobacterial blooms at the sub-pixel scale also benefited greatly (Zhang et al. 2014). Moreover, the works of the Boardman and Kruse also confirmed the superiority of using remote sensing technology for cyanobacterial blooms monitoring in our paper. Considering the continuity and integrity of scientific work, we have added citations in the Introduction and Discussion. Details at Line 69 and Line 518.
Boardman, J.W. (1993). Automating spectral unmixing of AVIRIS data using convex geometry concepts. In, JPL, Summaries of the 4th Annual JPL Airborne Geoscience Workshop. Volume 1: AVIRIS Workshop
Boardman, J.W. (1998). Post-ATREM polishing of AVIRIS apparent reflectance data using EFFORT: a lesson in accuracy versus precision. In, Summaries of the seventh JPL airborne earth science workshop (p. 53): JPL Publication Pasadena, CA
Boardman, J.W., Kruse, F.A., & Green, R.O. (1995). Mapping target signatures via partial unmixing of AVIRIS data
Kruse, F.A., Boardman, J.W., & Huntington, J.F. (2003). Comparison of airborne hyperspectral data and EO-1 Hyperion for mineral mapping. IEEE transactions on geoscience and remote sensing, 41, 1388-1400
Kruse, F.A., Boardman, J.W., & Lefkoff, A.B. (2000). Extraction of compositional information for trafficability mapping from hyperspectral data. In, Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI (pp. 262-273): SPIE
2 - My other suggestion for your very good paper is to define acronyms for readers not familiar with the subject.
Response: Thanks for this suggestion. We have added a “Acronyms list” at the beginning of the paper, including typical abbreviations found in papers, for readers not familiar with the subject. Please see Line 32-48 in detail.
Author Response File: 
Author Response.docx
Reviewer 2 Report
General comment:
The research topic in the paper "Innovative remote sensing identification of cyanobacterial blooms inspired from pseudo water color" is interesting and important because of permanent threats of cyanobacterial blooms to the environment and humans. The study proposed a new method, namely Pseudo Forel-Ule index (P-FUI), for the identification and monitoring of cyanobacterial blooms. The robust thresholds of the P-FUI parameters were determined based on satellite data, and the authors well proved the performance with comprehensive and quantitative assessment. The current manuscript provides important theoretical and technical support for the identification of cyanobacterial blooms in eutrophic lakes, and making progress in terms of its actual operational monitoring. However, I have several concerns as I explained below in detail. I suggest to accept the manuscript for publication in Remote Sensing after some revisions.
Detail comments:
(1) The current manuscript uses Lake Taihu as the research area to verify the algorithm, but I don’t seem to see the source of the verification data and the process of assessment. Please give more information of the process of assessment and make it easy to understand.
(2) From my point of view, a total of 23 figures are far too many for one paper. I wonder if all the figures in the article are necessary. For example, the figures in the discussion section (FIG. 16-23) might be better placed in the supplementary materials. I also found that many figures provide fragile information and can be moved to supplementary information, e.g., Figure 6 and 7.
(3) Figure 4: The step of “Water Extraction” used the index of MNDWI, if I understand correctly, this is to extract the water body, but why does the diagram of the extracted water body include the island part? If this is a display error, please correct, if there has other processing process, please explain in detail, so as not to cause misunderstanding to readers.
(4) Figure 9: this figure is for the flowchart of calculating P-FUI from satellite images. However, it looks like the FUI calculation flowchart. The "pesudo" should be emphasized here, such as indicating the replace of visible bands to VIS, NIR and SWIR bands. Similarly, this should be reflected in Equation (1).
(4) In the manuscript, improper or inconsistent expressions of lake names exist in several places, such as “Lake Dian” in Table 2, means “Lake Dianchi”? “Lesser Slave Lake”, “Buir lake” puts the "lake" in the back. Is that a fixed match? Similar confusion exists on “Line 136” and “Line 427”. Please check carefully to see if the same confusion occurs elsewhere.
(5) Some additional minor comments for the author to consider:
Line 112-113: km2 -> km2
Line 208: The italics in the formula seem different from the text later. Check that all formulas and their index numbers are in the correct format.
Line 232: The labels of the vertical axes in Figure 5 and 6 are inconsistent, please correct them.
Line 281: A punctuation (“:”) is missing at the end of the sentence.
Line 393: “P-FUI decision trees” is in plural form here, somewhat differently than elsewhere.
Line 530,533,537: “PFUI” -> “P-FUI”
Author Response
Reviewer 2#:
General comment:
The research topic in the paper "Innovative remote sensing identification of cyanobacterial blooms inspired from pseudo water color" is interesting and important because of permanent threats of cyanobacterial blooms to the environment and humans. The study proposed a new method, namely Pseudo Forel-Ule index (P-FUI), for the identification and monitoring of cyanobacterial blooms. The robust thresholds of the P-FUI parameters were determined based on satellite data, and the authors well proved the performance with comprehensive and quantitative assessment. The current manuscript provides important theoretical and technical support for the identification of cyanobacterial blooms in eutrophic lakes, and making progress in terms of its actual operational monitoring. However, I have several concerns as I explained below in detail. I suggest to accept the manuscript for publication in Remote Sensing after some revisions.
Detail comments:
(1) The current manuscript uses Lake Taihu as the research area to verify the algorithm, but I don’t seem to see the source of the verification data and the process of assessment. Please give more information of the process of assessment and make it easy to understand.
Response: Thanks for this comment. In this study, we evaluated the performance of the novel method with “ground truth”. First, we conduct field investigations to acquire basic information of water surface features, especially cyanobacterial blooms. Then, a total of 296 stratified random sample points were identified using photo-interpretation of the concurrent satellite images by expert visual interpretation. For easier reading, we have refined the relevant statement for the evaluation. Please see Line 360-364 in detail.
(2) From my point of view, a total of 23 figures are far too many for one paper. I wonder if all the figures in the article are necessary. For example, the figures in the discussion section (FIG. 16-23) might be better placed in the supplementary materials. I also found that many figures provide fragile information and can be moved to supplementary information, e.g., Figure 6 and 7.
Response: Thanks for this suggestion. We have reorganized the article structure to make sure it is clean and understandable to readers. In the revised paper, figure 6-7, figure 12 and figure 16-23 were moved to supplementary materials. Please see supplementary materials in detail.
(3) Figure 4: The step of “Water Extraction” used the index of MNDWI, if I understand correctly, this is to extract the water body, but why does the diagram of the extracted water body include the island part? If this is a display error, please correct, if there has other processing process, please explain in detail, so as not to cause misunderstanding to readers.
Response: Thanks for this comment. Figure 4 shows the flowchart of lake boundary extraction and calibration from satellite images. In order to obtain a more accurate lake boundary for images clipping, we first use the MNDWI index to identify the water area (Xu 2006), and then refined the shape by artificial correction based on expert experience. The result of this step is the lake boundary data. The previous figures did not express our meaning well, so we optimized the layout of Figure 4 again. So that one can understand it well. Please see Figure 4 in detail.
Xu, H. (2006). Modification of normalised difference water index (NDWI) to enhance open water features in remotely sensed imagery. International Journal of Remote Sensing, 27, 3025-3033
(4) Figure 9: this figure is for the flowchart of calculating P-FUI from satellite images. However, it looks like the FUI calculation flowchart. The "pesudo" should be emphasized here, such as indicating the replace of visible bands to VIS, NIR and SWIR bands. Similarly, this should be reflected in Equation (1).
Response: Thanks for this suggestion. Different from the FUI calculation, P-FUI calculation replaces the visible light band with the VIS, NIR, and SWIR bands, and uses the method of color space conversion to obtain CIE-XYZ. For different sensor types, the combination of bands assigned to R, G, and B channels is different. For sensors with SWIR bands, the band values of VIS, NIR, and SWIR were assigned to B, G, and R channels, respectively. For sensors without SWIR bands, the P-FUI parameters were calculated according to the combination of RGB channels "VIS–NIR–VIS". Considering that the description in the paper is not comprehensive enough, we have redrawn figure 9 (figure 7 after revised) to make it easier to understand. In addition, we further improved the expression of the sentence after Equation (1). Please see Figure 7 and Line 275-280 in detail.
(5) In the manuscript, improper or inconsistent expressions of lake names exist in several places, such as “Lake Dian” in Table 2, means “Lake Dianchi”? “Lesser Slave Lake”, “Buir lake” puts the "lake" in the back. Is that a fixed match? Similar confusion exists on “Line 136” and “Line 427”. Please check carefully to see if the same confusion occurs elsewhere.
Response: Thanks for this suggestion, there is indeed something inappropriate expressions in the name of the lake. The authors have checked it carefully now, and the lake names is now determined to be: Lake Taihu, Lake Chaohu and Lake Dianchi (Sun et al. 2013); Lake Hulun, Lake Buir and Lake Beloye (Orkhonselenge et al. 2022), Lake Atitlan (Rejmánková et al. 2011); Lake Kasumigaura(Alam et al. 2002); Lake Okeechobee (Canfield and Hoyer 1988); Lesser Slave Lake (Parlee et al. 2012). Moreover, we uniform the lake names in the paper and corrected some spelling mistakes.
Sun, D., Li, Y., Le, C., Shi, K., Huang, C., Gong, S., & Yin, B. (2013). A semi-analytical approach for detecting suspended particulate composition in complex turbid inland waters (China). Remote Sensing of Environment, 134, 92-99
Orkhonselenge, A., Uuganzaya, M., & Davaagatan, T. (2022). Lakes of Mongolia: Geomorphology, Geochemistry and Paleoclimatology. In A. Orkhonselenge, M. Uuganzaya, & T. Davaagatan (Eds.), Cham: Springer International Publishing
Rejmánková, E., Komárek, J., Dix, M., Komárková, J., & Girón, N. (2011). Cyanobacterial blooms in Lake Atitlan, Guatemala. Limnologica, 41, 296-302
Alam, M.G.M., Tanaka, A., Allinson, G., Laurenson, L.J.B., Stagnitti, F., & Snow, E.T. (2002). A comparison of trace element concentrations in cultured and wild carp (Cyprinus carpio) of Lake Kasumigaura, Japan. Ecotoxicology and Environmental Safety, 53, 348-354
Canfield, D.E., & Hoyer, M.V. (1988). The Eutrophication of Lake Okeechobee. Lake and Reservoir Management, 4, 91-99
Parlee, B.L., Geertsema, K., & Willier, A. (2012). Social-Ecological Thresholds in a Changing Boreal Landscape: Insights from Cree Knowledge of the Lesser Slave Lake Region of Alberta, Canada. Ecology and Society, 17
(6) Some additional minor comments for the author to consider:
Line 112-113: km2 -> km2
Line 208: The italics in the formula seem different from the text later. Check that all formulas and their index numbers are in the correct format.
Line 232: The labels of the vertical axes in Figure 5 and 6 are inconsistent, please correct them.
Line 281: A punctuation (“:”) is missing at the end of the sentence.
Line 393: “P-FUI decision trees” is in plural form here, somewhat differently than elsewhere.
Line 530,533,537: “PFUI” -> “P-FUI”
Response: Thanks for these suggestions. We have revised these spelling mistakes, and in addition, we have carefully checked elsewhere in the paper to prevent similar errors.
Author Response File: Author Response.docx
Reviewer 3 Report
This study develops a new method to identify the cyanobacterial bloom from remote sensing data. By adopting the Pseudo Forel-ULe index, this method significantly improves the accuracy. The experiment is well-designed and the results are sound, which shows the good scientific background of the authors on this topic. However, I still have a few comments, the English writing could be improved, especially in the Introduction section, and some spell checks are required.
Author Response
Reviewer 3#:
This study develops a new method to identify the cyanobacterial bloom from remote sensing data. By adopting the Pseudo Forel-ULe index, this method significantly improves the accuracy. The experiment is well-designed and the results are sound, which shows the good scientific background of the authors on this topic. However, I still have a few comments, the English writing could be improved, especially in the Introduction section, and some spell checks are required.
Response: Thanks for this comment. We have checked the English writing again of the paper carefully, and we also invited professional give more constructive advises to our English language editing. Make effort to a level suitable for reporting research in a scholarly journal.
Author Response File: Author Response.docx
