Evaluation of Geographical and Annual Changes in Rice Planting Patterns Using Satellite Images in the Flood-Prone Area of the Pampanga River Basin, the Philippines

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript mainly discusses the impact of flood disasters on planting patterns, which is of great scientific significance and social value for studying the impact of flood disasters on agricultural production and even human socioeconomic activities. The manuscript uses the clustering and stratification method to conduct relevant research and achieve certain results. However, the introduction of research data and research methods in the manuscript is too simple, which is not conducive for readers to read and understand the research process of the entire manuscript. At the same time, the manuscript only has discussions and no conclusions. This is a major flaw in the structure of the manuscript. Therefore, the authors are advised to make major revisions to the manuscript.

Section 2.2: The introduction of study data is too simple. The data processing method, the institution providing it, and the source of future data downloads should be explained.

Section 2.3: There are many methods of clustering and stratification. It is recommended to introduce the basic principles of clustering and stratification, and the standards of stratification, and give the basic companies of clustering and stratification.

Section 2.4: It is recommended to briefly introduce the basic situation of Google Earth Engine and Quantum Geographic Information system

Section 3.2 One sentence becomes a chapter, which is unreasonable.

Limitations of the manuscript study and directions for future work should be added to the discussion.

Manuscript lacks conclusion.

Author Response

The manuscript mainly discusses the impact of flood disasters on planting patterns, which is of great scientific significance and social value for studying the impact of flood disasters on agricultural production and even human socioeconomic activities. The manuscript uses the clustering and stratification method to conduct relevant research and achieve certain results. However, the introduction of research data and research methods in the manuscript is too simple, which is not conducive for readers to read and understand the research process of the entire manuscript. At the same time, the manuscript only has discussions and no conclusions. This is a major flaw in the structure of the manuscript. Therefore, the authors are advised to make major revisions to the manuscript.

・Thank you for your valuable comments. We have made the following corrections to the points you raised. In particular, we have described future applications and issues in the conclusion section.

 

Section 2.2: The introduction of study data is too simple. The data processing method, the　institution providing it, and the source of future data downloads should be explained.

・We added sentences about the institution to the first sentence of Section 2.2.:

MODIS data (MCD15A2H) provided by NASA were downloaded for the 16 years from 2007 to 2022. MCD15A2H provides Leaf Area Index (LAI) values with 500 m pixel size every 8 days.

・We also added the following sentences about the data processing method to the Section 2.2. :

Leaf Area Index defined the one-sided green leaf area per unit ground area. In this product, LAI is estimated by a main Look-Up-Table (LUT) based procedure that exploits the spectral information content of the MODIS red (648nm) and near-infra-red (NIR; 858nm) surface reflectance, and the back-up algorithm that uses empirical relationships between Normalized Difference Vegetation Index (NDVI) and canopy LAI and FPAR [19].

・We were not sure about the mean of the source of future data downloads, so we didn’t mention it.

 

Section 2.3: There are many methods of clustering and stratification. It is recommended to introduce the basic principles of clustering and stratification, and the standards of stratification, and give the basic companies of clustering and stratification.

・We added following sentences to the Section 2.3.:

In this study, Hierarchical clustering was performed on the extracted LAI data to group based on the similarity. Among several clustering techniques, hierarchical clustering was selected due to its efficiency when trends in the data were unknown in the advance.

 

Section 2.4: It is recommended to briefly introduce the basic situation of Google Earth Engine and Quantum Geographic Information system

・We added following two sentences about Google Earth Engine and QGIS to the Section 2.4.:

Google Earth Engine is a cloud-based geospatial analysis platform that enables users to visualize and analyze satellite images of our planet [21].

QGIS is a free, open software that allows users to create, edit, visualize, analyze, and publish geospatial data.

 

Section 3.2 One sentence becomes a chapter, which is unreasonable.

・We added following sentences to the Section 3.2.

The results of clustering by year for each area are follows. Different LAI dynamics were presented in each area.

 

Limitations of the manuscript study and directions for future work should be added to the discussion.

Manuscript lacks conclusion.

・We add to the following Conclusion that describe Limitations of the manuscript study and directions for future work.

In this study, the long-term time-series MODIS LAI product were used to analyze cultivation patterns in Candaba from 2007 to 2022. The two-stage clustering allowed to detect regions and years with different LAI dynamics influenced by flood. However, the results also suggest that higher resolution and more accurate LAI evaluation were required to evaluate flood damage precisely. SAR sensor can observe the ground status in the rainy season, and detect waterbodies due to flooding. Since the evaluation of vegetation by SAR still has low accuracy, evaluation of cultivation patterns in this study would contribute to achieve more accurate flood damage assessment.

 

Reviewer 2 Report

Comments and Suggestions for Authors

The experimental topic is a current and important area. The importance and usefulness of data collected by remote sensing is constantly increasing.

 

Introduction

 

The amount of damage should be written in dollars, not pesos. And you mentioned the usfulness of the sattelites, but should discribe and explane more detailed. More references from the last three years should be included in the article.

 

Could you explain this sentences? –„Such an analysis would provide important infor- 49 mation, helping to evaluate how farmers have adapted to flooding and to develop coun- 50 termeasures for the future.”

 

Materials and methoods

 

Please describe the diferences between the two cluster analyses. 

 

Please discribe more deatailed the calculation form in QGIS

 

Should put in the methoods the main meterological parameters of the examined years.

 

Discussion

 

Should write more result, because the article have more results. Please describe the individual changes between the clusters in more detail per year.

 

Was there a change in cultivation technology during the examined period? How can it be related to the result?

 

 

​How could you explain the statement below?

„Cluster 2 in Area 3, which widely occupied the area in 2015 and 2020, probably indicates that the rice was damaged and delayed by one month.”

Author Response

The experimental topic is a current and important area. The importance and usefulness of data collected by remote sensing is constantly increasing.

・Thank you for your valuable comments. We revised the manuscript based on the comments,

surely enhancing the information to the readers.

 

Introduction

 

The amount of damage should be written in dollars, not pesos. And you mentioned the usfulness of the sattelites, but should discribe and explane more detailed. More references from the last three years should be included in the article.

・We added following two sentences to the Introduction.：

For example, during Typhoon “ULYSSES”, 4490 hectares of farmland were damaged throughout the entire province of Pampanga, with agricultural damage amounting to about 200 million pesos (about 3.8 million USD) [5].

In addition, various applications have been tried for the evaluation methods, ranging from statistical methods such as linear regression [12] to deep learning [13].

 

Could you explain this sentences? –„Such an analysis would provide important infor- 49 mation, helping to evaluate how farmers have adapted to flooding and to develop coun- 50 termeasures for the future.”

・We added following sentences to the Introduction.：

For example, farmers can consider their responses and the government can develop a regional strategy based on the flood risk. These scientific countermeasures may also increase the resilience to future floods under climate change.

 

Materials and methoods

 

Please describe the diferences between the two cluster analyses. 

・To clarify the two stage clustering, we added a new figure.

 

Please discribe more deatailed the calculation form in QGIS.

・We added following sentences to the Section 2.4.:

After shape file was created for each pixel of GLCNMO, the average LAI was extracted for each range of shape.

 

Should put in the methoods the main meterological parameters of the examined years.

・I'd like to discuss whether we really need to add.

 

Discussion

 

Should write more result, because the article have more results. Please describe the individual changes between the clusters in more detail per year.

Was there a change in cultivation technology during the examined period? How can it be related to the result?

・To respond these two points, the following sentences was added to discussion.:

The changes in cultivation patterns were also influenced by advances in agricultural technology, such as the construction of irrigation water. In fact, some farmers increased the number of plantings owing to the irrigation water availability (personal communication). Popularization and enlargement of agriculture machinery might also affect the cultivation patterns [26].

 

How could you explain the statement below?

„Cluster 2 in Area 3, which widely occupied the area in 2015 and 2020, probably indicates that the rice was damaged and delayed by one month.”

・We added following sentences to the discussion.:

a small peak just before the dry season peak might mean that farmers started the cultivation as usual year but failed it by flood; they might restart the cultivation after flood which caused about one month delay of the dry season peak (Figure 8).

Reviewer 3 Report

Comments and Suggestions for Authors

This is a communication paper entitled “Evaluation of geographical and annual changes in rice planting patterns with satellite images in flood-prone area of Pampanga River Basin, the Philippines”. In this paper, MODIS LAI data (MCD15A2H) from 2007 to 2022 were to evaluate annual and geographical differences in cultivation patterns in the Candaba municipality of the basin. Two stages of hierarchical clustering were employed to classify the areas and annual LAI dynamics, respectively. As the authors mentioned, the results of this study provides an effective tool for the analysis of MODIS LAI data when considering cultivation patterns characterized by annual and geographical differences. I have some comments summarized as follows:

1. LAI data include outliers, so how to solve the issue of outlier or how to choose more robust methods to analyze the data?

2. Lines178-181. Please provide any references to clarify this important finding?

3. Lines 215-217. Please explain more about the meaning of these sentences.

4. Lines 252-254. Please explain more about the meaning of these sentences.

Author Response

This is a communication paper entitled “Evaluation of geographical and annual changes in rice planting patterns with satellite images in flood-prone area of Pampanga River Basin, the Philippines”. In this paper, MODIS LAI data (MCD15A2H) from 2007 to 2022 were to evaluate annual and geographical differences in cultivation patterns in the Candaba municipality of the basin. Two stages of hierarchical clustering were employed to classify the areas and annual LAI dynamics, respectively. As the authors mentioned, the results of this study provides an effective tool for the analysis of MODIS LAI data when considering cultivation patterns characterized by annual and geographical differences. I have some comments summarized as follows:

Thank you very much for your kind comment.

 

1. LAI data include outliers, so how to solve the issue of outlier or how to choose more robust methods to analyze the data?

・We added following sentences to the Section 2.2.:

Since the positions of GLCNMO and MCD15A2H do not necessarily match, the average of the LAI values of all MCD15A2H pixels in the range of GLCNMO pixels was used as the LAI of the pixels.

 

2. Lines178-181. Please provide any references to clarify this important finding?

・Since we can not find an example of two stage clustering, we add a figure to support our finding.

 

3. Lines 215-217. Please explain more about the meaning of these sentences.

・We added following two sentences to the discussion.:

Accordingly, the tendency of lower peaks in the rainy season may be due to the lower accuracy of LAI product and the inconsistency of cultivation periods in the same pixel.

The relationship between LAI dynamics and rice production will be analyzed in a next study.

 

4. Lines 252-254. Please explain more about the meaning of these sentences.

・We added following sentences to the discussion.:

the inundation detected by SAR can be judged as natural flooding or paddy field preparation based on the cultivation period.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I thank the authors for their time and effort, which has resulted in a substantial improvement in the quality of the manuscript. Here is another small suggestion. It is recommended that the authors add a description of the geographic location and environment of the study area. It is recommended that the manuscript be published after minor revisions

Author Response

I thank the authors for their time and effort, which has resulted in a substantial improvement in the quality of the manuscript. Here is another small suggestion. It is recommended that the authors add a description of the geographic location and environment of the study area. It is recommended that the manuscript be published after minor revisions.

Thank you for the comments. We addid the location and climate zone classification in L73. 

 

 

Reviewer 3 Report

Comments and Suggestions for Authors

No further question.

Author Response

Thank you for your confirmation.