Round 1

Reviewer 1 Report

Line 23: "... WT ..." – the abbreviation at the first mention should be decoded.

Line 45: "... Areas ..." – no need to use a capital letter.

Line 50: "... day. [1]" – extra point.

Line 55: "... [3].The..." – add a spacebar.

Line 61: "... 6.7%. [4]" – extra point.

Line 157: "... point and P the target ..." – not clear, better to reword.

Line 195: "... square kilometers ..." – better to replace by "km²" as throughout the text.

Figure 7: – better to start the name of the axis with a capital letter.

Figures: – please add scale and North direction where required (fig. 4, 6).

Text formatting: need revision, check use of “bold” (e.g. lines 291-295).

Author Response

Response to Reviewer 1 Comments

 

Point Comments

Line 23: "... WT ..." – the abbreviation at the first mention should be decoded.

 

Line 45: "... Areas ..." – no need to use a capital letter.

 

Line 50: "... day. [1]" – extra point.

 

Line 55: "... [3]. The..." – add a spacebar.

 

Line 61: "... 6.7%. [4]" – extra point.

 

Line 157: "... point and P the target ..." – not clear, better to reword.

 

Line 195: "... square kilometers ..." – better to replace by "km²" as throughout the text.

 

Figure 7: – better to start the name of the axis with a capital letter.

 

Figures: – please add scale and North direction where required (fig. 4, 6).

 

Text formatting: need revision, check use of “bold” (e.g. lines 291-295).

 

Response 1: for Point 1.

The abbreviation added in Line 23

 

Response 2: for Point 2.

The capital letter changed into lowercase in Line 45

 

Response 3: for Point 3.

Extra point was deleted in Line 50

 

Response 4: for Point 4.

A spacebar added in Line 55

 

 

Response 5: for Point 5.

Extra point was deleted in Line 61

 

Response 6: for Point 6.

Revised it by added tobe “is” after P in Line 157

 

Response 7: for Point 7.

“square kilometer” changed to “km²” in Line 205

 

Response 8: for Point 8.

The name of all axis in Figure 7 start in capital letter in Line 262

 

Response 9: for Point 9.

Added North direction for Figure 4 in Line 201 and for figure 6 already added (6c), but for images in range and azimuth mode (Figure 6 (a) and (b)) in Line 233 no need north direction.

 

Response 10: for Point 10.

Bold text was changed to normal text in Line 291-295

Reviewer 2 Report

General comment:

 

This paper concerns the use of SAR interferometry on ALOS-2 PALSAR data and real-time in-situ measurements in order to monitor changes of Water Table Depth. This is a very important work as these changes of Water Table Depth are inducing a subsidence and are one of the health indicators of the forests. Bringing together precise and real time in-situ measurements together with large satellite measurements should allow to monitor precisely large areas of tropical forests.

 

The paper is particularly well written and represents a significant contribution to this field. However, while the validation part is solid and well detailed, the theoretical part (SAR interferometry) is not clear. A light improvement of this theoretical part would greatly improve the scientific impact of this paper.

Detailed comments:

 

P.1 L.21: “… into WT depth data…” Please provide there the meaning of the acronym WT: “… into Water Table (WT) depth data…”.

P.3 L.97: “… time GW Depth…” Please provide there the meaning of the acronym GW: “… time Ground Water (GW) Depth…”

P.3 L.107: Please remove the acronym “WT” from this sentence, as it was introduced earlier.

P.3 L.129-130: “Since microwave … generate them.”: This is superficial: the most important parameter here is the precision of the instrument and effects of the ionosphere and troposphere. Of course, for a given phase error, if the frequency increases, the related error in distance decreases, but the vertical ambiguities will be closer (the phase unwrapping will be more difficult…). Please develop the original sentence to include that type of concerns.

P.4 L.142: This equation seems to be wrong: Phi_ik should be a difference of the two phases and not a multiplication. As Phi_ik is a difference, it could be also noted with a “Delta_Phi”. The equation related to the coherence could be also provided, together with an explanation of why the coherence is important (low coherence -> low precision of the phase)

P.4 L.150: A figure presenting all the geometrical parameters introduced in the paper (points O, P, distances Bn, Delta_n, Delta_R, Rk, theta…) should be added somewhere in the paper.

P.5 L.153: The transition from the previous equations to this one is not clear. In addition, it there should be an additional “Delta_Phi_ik” on the right part of the equation, related to the displacement between two images.

P.5 L.156: “The ambiguity height was Delta_ha, the height that generates…” This sentence is unclear and should be rephrased.

P.6 L.160: The transition from the equation (7) to this one is not clear. The Delta_phi_DinSAR value corresponding to a vertical displacement should be introduce before in the paper.

P.6 L.162: Please move there the definition of GWT.

P.7 L.194: “… not all area coherence was due to the existence…” This sentence is unclear. Please rephrase it. It could be something like that: “The interferogram could not be generated on the entire image due to large temporal decorrelation” (if this was the proper meaning of the original sentence).

P.9 L.214: I the figure, there is twice the blue and red colors for different things. Please avoid duplicates of colors in the map and in the legend.

P.10 L.228: In the figures, there seems to be two different colors for the plot of the soil moisture. Could these soil moisture plots be harmonized?

P.13 L.313: The name and surname of the authors are wrong (https://www.jstor.org/stable/24432333?seq=1#page_scan_tab_contents). Please add the usual information for publication (“Vol. 25, Nb 1, January 2015. DOI: 10.1890/13-2014.1”).

P.14 L.316: The URL cannot be reached. In general, please avoid URLs in references, when possible.

P.14 L.320: Please add the ISBN (“ISBN: 978-90-327-0357-8”) in order to find the paper more easily in case of broken URL.

P.14 L.346: Please add the ISNI (“ISNI: 0000 0004 2714 2033”) in order to find the paper more easily in case of broken URL.

Author Response

Response to Reviewer 2 Comments

 

Point of Comments

1 L.21: “… into WT depth data…” Please prov ide there the meaning of the acronym WT : “… into Water Table (WT) depth data…”. 3 L.97: “… time GW Depth…” Please prov ide there the meaning of the acronym GW: “… time Ground Water (GW) Depth…” 3 L.107: Please remove the acronym “WT” from this sentence, as it was introduced earlier. 3 L.129-130: “Since microwave … generate them.”: This is superficial: the most important parameter here is the precision of the instrument and effects of the ionosphere and troposphere. Of course, for a given phase error, if the frequency increases, the related error in distance decreases, but the vertical ambiguities will be closer (the phase unwrapping will be more difficult…). Please develop the original sentence to include that type of concerns. 4 L.142: This equation seems to be wrong: Phi_ik should be a difference of the two phases and not a multiplication. As Phi_ik is a difference, it could be also noted with a “Delta_Phi”. The equation related to the coherence could be also prov ided, together with an explanation of why the coherence is important (low coherence -> low precision of the phase) 4 L.150: A figure presenting all the geometrical parameters introduced in the paper (points O, P, distances Bn, Delta_n, Delta_R, Rk, theta…) should be added somewhere in the paper. 5 L.153: The transition from the prev ious equations to this one is not clear. In addition, it there should be an additional “Delta_Phi_ik” on the right part of the equation, related to the displacement between two images. 5 L.156: “The ambiguity height was Delta_ha, the height that generates…” This sentence is unclear and should be rephrased. 6 L.160: The transition from the equation (7) to this one is not clear. The Delta_phi_DinSAR value corresponding to a vertical displacement should be introduce before in the paper. 6 L.162: Please move there the definition of GWT . 7 L.194: “… not all area coherence was due to the existence…” This sentence is unclear. Please rephrase it. It could be something like that: “The interferogram could not be generated on the entire image due to large temporal decorrelation” (if this was the proper meaning of the original sentence). 9 L.214: I the figure, there is twice the blue and red colors for different things. Please avoid duplicates of colors in the map and in the legend. 10 L.228: In the figures, there seems to be two different colors for the plot of the soil moisture. Could these soil moisture plots be harmonized? 13 L.313: The name and surname of the authors are wrong (https://www.jstor.org/stable/24432333? seq=1#page_scan_tab_contents). Please add the usual information for publication (“Vol. 25, Nb 1, January 2015. DOI: 10.1890/13-2014.1”). 14 L.316: The URL cannot be reached. In general, please avoid URLs in references, when possible. 14 L.320: Please add the ISBN (“ISBN: 978-90-327-0357-8”) in order to find the paper more easily in case of broken URL. 14 L.346: Please add the ISNI (“ISNI: 0000 0004 2714 2033”) in order to find the paper more easily in case of broken URL.

 

Response 1: response for Point 1

Added in P1 - Line 23

 

Response 2: response for Point 2

All of the word “GW” in this paper changed into “WT”

 

Response 3: response for Point 3

Already deleted it, please check in P-1 Line 116

 

Response 4: response for Point 4

This sentence has been deleted because the research method has been refined

 

Response 5: response for Point 5

This equation was deleted it and about coherence explained in Equation (2) and P-5 Line 149

 

Response 6: response for Point 6:

Added Figure 3 in P 6 Line 159

 

Response 7: response for Point 7:

Already modified in P-6 Line 166 - 171

 

Response 8: response for Point 8:

Already revised all in P6 – Line 175-177

 

Response 9: response for Point 9:

Added new equation and sentence from Line 167 – 177 in Page 6 as transition explanation.

 

 

Response 10: response for Point 10:

All oacronym GWT already delete it in this paper

 

Response 11: response for Point 11:

The sentence revised as shown in Page 9 Line 226-227

 

Response 12: response for Point 12:

The same color of layer and legend of  Map (Figure 8) was revised into another color in Page 14 Line 312

 

Response 13: response for Point 13:

All of soil moisture line color in Figure 7 was revised into harmonic color in Page 12 Line 262

 

Response 14: response for Point 14:

Already deleted it

 

Response 15: response for Point 15:

Revised and avoid using URL

 

Response 16: response for Point 16:

Revised and avoid using URL

 

Response 17: response for Point 17:

Revised and avoid using URL

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.