Temporal Subset SBAS InSAR Approach for Tropical Peatland Surface Deformation Monitoring Using Sentinel-1 Data

Round 1

Reviewer 1 Report

This article presents the new approach for processing satellite radar interferometry data Temporal Subset SBAS InSAR to monitor surface subsidence of peatlands areas in Southeast Asia.
The proposed methodology was based on increasing the CS points density within the analyzed research polygons. For this purpose, the analyzed period of 3 years (2018-2020, WHOLE) was divided into annual periods (2018, 2019, 2020, SUBSET). Consequently, a different number of CS points in each subset was obtained. The proposed solution was evaluated based on simulated data and then compared selected aspects of WHOLE and SUBSET methods.
The research used spatial data: precipitation sums, maximum temperatures, land use land cover (LULC) maps, fire hotspots, which allowed to additionally link changes in the natural environment with changes observed using the Temporal Subset SBAS InSAR .

The research focused on optimization of the proposed Temporal Subset SBAS InSAR method, based on simulated data. Land surface deformation was presented against the background of LULC changes, NDVI index changes and number of CS points. However, the results of a direct comparison of surface subsidence from two methods of computation (sum of SUBSETs and WHOLE) are missing. What the title of the article directly refers to.

In addition, the discussion or the introduction does not include the description of other articles dealing directly with the monitoring of surface subsidence of peatlands areas, e.g. the ISBAS InSAR method, as well as their advantages and disadvantages.

You present new methods of land surface monitoring and it worth to compare with classical geodetic measurements.  Is there any possibilities to compare Temporal Subset SBAS results with any geodetic measurements to evaluated them.  It could be also GNSS receivers presented in the figure 1.

Please correct acronym in row 471 of NDVI index.

 

Author Response

Point by point response are given as PDF file. 

Author Response File: Author Response.pdf

Reviewer 2 Report

This is an intresting paper, which not only presents an efficient SBAS InSAR technique for the tropical peatland surface deformation monitoring where dynamic surface scatterers change exists, but also  provides a schem of color representation of coherent scatterers (CS) temporal behavior for the visual interpretation of scatterer change. However, this paper should be improved extensively before it can be accepted for publication. My comments are as follows:

1) The references need to be updated. Please cite more papers pulished in the last 5 years properly.

2)  The research situation of the related works are not adequately introduced. Especially, some researchers have also studied the issue of the deformation monitoring for those areas with highly dynamic surface scatterers change using InSAR technique, but the authors only simply introduced one paper.

3) The main problem of this paper is that the innovation is not well introduced. As in Comment 2), some researchers have also studied the issue of the deformation monitoring for those areas with highly dynamic surface scatterers change using InSAR technique, so, what's the innovation of this paper with regard to those ones?

4) Section 2.2, I suggest the authors to use some change detection approach to show the change of the land cover, which can further help the readers better grasp the basic information of the study area. Similarly, try to display the original sentinel-1 images or optical images of the study area in some places.

5) Line 262, "The pixels with higher ? than a predefined threshold of 0.65 are selected as CS in our processing." How was this threshold determined?

6) In the Figures, change "tau" in the legend to the symbol.

7) Figure 13, how was the land cover map obtained, by visual interpretation  from remote sensing images? by computer interpretation （such as supervised classification） from remote sensing images？ or by other means?

8) By now, the conclusion section seems to like a simple extension of the abstract, which needs to be enhanced.

Author Response

Point-by-point response is given as PDF file. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors referred to all comments and remarks and made corrections / changes to the article. I accept the article as it stands.

Author Response

We did a additional correction in English throughout the manuscript. Accordingly, title is bit changed. 

Reviewer 2 Report

This paper is OK for publication now.

Author Response

We did additional corrections in English throughout the manuscript. Accordingly, the title is a bit changed.