Spatiotemporal Distribution Pattern and Driving Factors Analysis of GPP in Beijing-Tianjin-Hebei Region by Long-Term MODIS Data

Round 1

Reviewer 1 Report

Please check the attached document

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

 

Thanks very much for taking your time to review this manuscript. I really appreciate all your comments and suggestions! At the same time I have made a lot of adjustments to the English language and style. Please find my itemized responses in below and my revisions/corrections in the re-submitted files.

 

Thanks again!

Author Response File: Author Response.docx

Reviewer 2 Report

This study analyze driving factors of GPP in BTH from 2000-2020. Generally, the logic flow is good and the presentation is clear. I just have some minor comments for improving this study.

L22 the unit should be constant, such as gC m-2 yr-1 or gc/m2/yr.

L55 What is Geodetector? Please added one sentence for describing this before you used it.

S2.2.1 please point out which version of MODIS GPP product you used, since MODIS v5 and MODIS v6 is very different.

L 119-121 it is a bit confusing here. The authors accumulated GPP from April to October, but the Spring from March to May, Autumn from September to November, so do you accumulated GPP at March and November during the year?

Figure 2 why the authors just used GPP at 2000, 2005, 2010, 2015, 2020 but not all the available years? Besides, please make sure the resolution of figures is clear enough.

Figure 4-5, please added the p-value for the fitting line. This helps to show whether the trend is significant or not.

Figure 7 please delete the xx.tif in the figure legend.

Author Response

Dear Reviewer,

 

Thanks very much for taking your time to review this manuscript. I really appreciate all your comments and suggestions! At the same time I have made a lot of adjustments to the English language and style. Please find my itemized responses in below and my revisions/corrections in the re-submitted files.

 

Thanks again!

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript is focused on Gross Primary Production Data and their analyses by various methods via selected ecological and human-induced factors in Beijing-Tianjin-Hebei Region. Input data of GPP have been taken from MOD17 datasets of NASA EOS program and all other data (precipitation, land surface temperature etc.) have also been taken from different databases cited in manuscript. The main goal of the study has been analysed the importance of analysed factors on spatial and temporal variation and identification of the importance of individual factor on the temporal and spatial variation of GPP. Two statistical methods have been used: Man-Kendall trend test and Pearson Correlation. All data have been analysed in resolution grid 500 x 500 m and time period 2000-2020. The statistical methods have been used correctly as well as the results comments, but it is necessary to add some general comments to methodology and results:

1. The grid resolution (500x500 m) for GPP analysis is relatively large and is suitable for global studies not regional.

2. The manuscript did not offer important supported data such e.g. land cover data (forests, grasslands, arable lands, urban lands, ...) and their changes (temporal, spatial) what is very important for interpretation of the results.

3. The selection of the analysed factors in relation to GPP especially the land surface temperature (LST) and night time light (NLT) are not very good (I know that these factors are very good to obtain from satellite observations). LST is not a primary factor before is a result of interaction of radiation balance, evapotranspiration and land type, therefore the influence of LST on GPP could be covered by interactions of  mentioned processes. Similarly, the NLT influence could be recovered by the night temperature change (and their influence on respiration) etc.

Technically the statistical analyses are correct, but I strongly recommend the wider discussion and very care interpretation of the results in the light of the above mentioned remarks. 

Author Response

Dear Reviewer,

 

Thanks very much for taking your time to review this manuscript. I really appreciate all your comments and suggestions! At the same time I have made a lot of adjustments to the English language and style. Please find my itemized responses in below and my revisions/corrections in the re-submitted files.

 

Thanks again!

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Please refer to the attached file

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thanks very much for taking your time to review this manuscript. I really appreciate all your comments and suggestions! Please find my itemized responses in below and my revisions/corrections in the re-submitted files.

Thanks again!

Author Response File: Author Response.docx