Simulating Heat Stress of Coal Gangue Spontaneous Combustion on Vegetation Using Alfalfa Leaf Water Content Spectral Features as Indicators

Round 1

Reviewer 1 Report

The manuscript entitled: "Simulating heat stress of coal gangue spontaneous combustion on vegetation using alfalfa leaf water content spectral features as indicators" aims at developing a strategy for vegetation heat-stress assessment in coal gangue dump reclamation areas. In order to achieve this goal, a spectral feature-based long short-term memory model was built. 
The manuscript is clear, and the conclusions drawn from the author are supported by the results. I have only minor comments that could improve the manuscript:
C1)  I would suggest the authors to avoid using capital letters after semicolon. 

C2) The authors have discussed cross-validated results (for instance, Fig7) but they refer to RMSE or R^2. Since these entities are internally validated,  I suggest to the authors to refer to these as RMSECV and R^2_CV. 

C3) I think it would be interesting for the readers to look at all the raw and preprocessed spectra; consequently, I think a plot showing these signals could be included into the manuscript (or into the supplementary material). 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments to authors

This manuscript entitled “Simulating heat stress of coal gangue spontaneous combustion on vegetation using alfalfa leaf water content spectral features as indicators” presents the ability to use a spectral feature-based long short-term memory (SF- LSTM) model to estimate alfalfa's heat stress level. Through a temperature gradient experiment, the water content data (live fuel moisture content, relative water content, and equivalent water thickness) and leaf spectrum were collected at different times. The subject is very important and the structure of the manuscript is complete. However, there are still several issues that require further consideration.

• There is no information about the experimental design
• There is no information about the data analysis for the three water content data (LFMC, RWC, and EWT), which presented in Figure 4.
• It is important to present the alphabet letter in Figure 4 to show the significant differences between temperature treatments within each measurements date.
• It is important to present the data regarding the actual temperature of soil around the root zone of the alfalfa plant for each temperature treatment.
• There is a conflict between the two sentences Lines 130-131 “The spectral reflectance of leaves was measured between 10:00 and 14:00 on sunny and windless days.” And Lines 131-132 “The spectral data were collected eight times until November 15, 2020, when it was overcast and rainy.”
• The portable ground object spectrometer was used as active or passive reflectance sensing to detect the spectral reflectance of leaves; please confirm it.
• Lines 133-134 “This was clamped to the middle part of a leaf sample to measure its spectrum”. This sentence is not clear. How many leaves were used to measure the spectral reflectance in each time? The reflectance spectrum was measured for the adaxial or abaxial faces of leaves
• Lines 139-140: “three alfalfa samples were selected for each treatment”. What does this sentence mean? It means that the authors selected three leaves or three plants.
• In Table (1), where the reference [46]. Please check all Ref.
• Lines 276-277 “the differences in LFMC, EWT, and RWC between each experimental group were small” as I mentioned above, it is important to analyze the data of Figure 4. Based on the statistical analysis, this sentence will be changed into “the differences in LFMC, EWT, and RWC between each experimental group were non-significant or significant”
• Line 281 please change “other experimental groups” into “other treatment of temperature groups” please follow this sentence in all manuscript
• Lines 286-287 “there was no significant difference in RWC between the control and experimental groups” this sentence indicate that the statistical analysis for the data of Figure 4 should be done and the alphabet letter of the mean differences among the treatments groups for each date should be shown in Figure 4.
• Line 287 “After heating the soil layer” It is important to present the data of actual soil layer temperature around the root zone.
• The Coefficients of correlation presented in Figure 5 is the average reflectance spectrum of eight measurements, please confirm this.
• Table 2. In general, the spectral reflectance indices (SRIs) are usually categorized into two types: vegetation and water-SRIs. Please identify the SRIs in Table 2 which one is vegetation-SRIs and water-SRIs.
• The values of coefficients of correlation (r) in Table 2 are significant or not. Please mention it under the table as a footnote.
• Lines 431-432 “Root system growth has a huge impact on the dry and fresh weights of the plant leaves” This sentence indicates that it is important to monitor the actual soil temperature around the root zone.   
• The conclusion should be written in one paragraph.
• In many places in the abstract, the semicolon (;) should be changed into full stop (.)

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

thanks for authors 

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