Study on the Influence of Vegetation Restoration on Evapotranspiration in Mountainous Areas of the Luan River Basin

Round 1

Reviewer 1 Report

GENERAL COMMENTS

The manuscript presents a study of the evapotranspiration effects on runoff in an important river basin area in China. The aim is to see if the vegetation restoration over large areas has decreased the runoff, and reserves for socio-economic water use.

For areas with primaly only remote observation the comparison of determined evapotranspiration and NDVI is also an important part in the manuscript.

As it is said that average annual temperature in some parts is below zero, I would like to see some additional discussion on how the solid precipitation periods affect runoff, and how evapotranspiration model is applicable during these seasons. Possible climate warming could also have different impact on areas with seasonal snow cover. You only have a brief comment related to this in the end of the "Discussion" chapter.

COMMENTS ON DETAILS

1. Figure 4 has two quantities, and you should clearly indicate which is which in the plot.

2. Lines 268-271 discussion on evapotranspiration and NDVI.: "evapotranspiration is not only influenced by vegetation NDVI but also by various climate factors". Influenced by vegetation sounds OK, but influenced by an index is not so. The text would need a slight modification perhaps. On the other hand you could refer to the equations you have used for calculation of evapotranspiration.

3. In the discussion on lines  353-354 "there are uncertainties in the results of this study" sounds like this was a big disappointment to the writers. However, uncertainty is what is to be expected in exact sciences, and estimates of the uncertainty are essential part of the studies.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

It is an interesting paper. Sub-section "2.2.1 Method" needs extensive revision. The concept of the analysis presented there is not clear (see also remarks below). Although English of the text is generally OK, in sub-section 2.2.1 it is difficult to understand.  

Particular remarks:

Line 137 " Ga ... calculated from Eq. (2)". What is Gi in this equation? 

Line 140: Cc is not given by Eq. (3) but by Eq. (4). 

What is Qh in Eq. (4) ?

Line 147 " Not very sensitive, soil evaporation ...." what does this sentence mean?

Lines 166-167: Here appears "watershed I" , which is not yet introduced.

Lines 161-162: "gsx ... is a calibrated parameter ... ". Which are the other calibrated parameters? 

How is Ga calculated owing to the fact that it is a function of Gc (Eq. 2) and Gc is according to Eq. 4 a function of the calibration parameter gsx? 

Lines 170-172: Which components of the water budget are considered in the water balance equation of the three sub-regions, how these components have been estimated or measured and which is the time scale of the water balance equation?    

Figure 2: What do the three graphs in Fig. 2 show? The graphs are not mentioned or discussed in the text. What is the procedure of calibration and what is the verification?  

Sub-chapters 3.1 and 3.2 have the same title

Line 230: According to the results in Figure 5, the highest value occurred in the year 2014 and not in 2012. 

Line 232: It is Figure 6(a) and not Figure 5(a). 

For which region is the graph in Figure 7(a) valid? The graph seems to be similar to that of Watershed I in Fig. 2. In the text there is no reference to Fig 7(a). 

Same question for Fig. 7(b). What does the phrase "(b) The relationship" in the caption of Fig. 7(b) mean?    

Lines 278-282: What is in this section compared with what?

Lines 300 and 302: Use evapotranspiration as in the text instead of evaporation. 

Lines 305-306: How is the effect of rainfall fluctuations removed from runoff? 

English in the text is generally OK, however section 2.2.1 needs a systematic reconsideration. 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Line 149: "fects" it should be probably "reflects"

Lines 151-156: "Zhang[33] pointed out ... results". Which results are meant here? These should be something different than "the vegetation evaporation results" mentioned in the next sentence. Otherwise there is a contradiction between the two sentences in the lines 151-156.

Lines 277-287: In the text there is no reference to Fig. 7(a)   

Lines 171-172: "Since ... Luan River Basin", check the meaning of this sentence. It seems to be incomplete.   

some minor editing required

Author Response

Thank you very much for your professional and meticulous comment, and we have made careful revisions according to your suggestions

Line 149: "fects" it should be probably "reflects"

Response: Thank you very much for pointing out the problem. The author corrected the wrong word.

Lines 151-156: "Zhang[33] pointed out ... results". Which results are meant here? These should be something different than "the vegetation evaporation results" mentioned in the next sentence. Otherwise there is a contradiction between the two sentences in the lines 151-156.

Response: We changed the difficult sentence to ” Zhang[33] pointed out that in areas with better vegetation conditions, f has less effect on simulated results of evapotranspiration.”

Lines 277-287: In the text there is no reference to Fig. 7(a)

Response: We added the reference Fig 7 (a) in line 274

Lines 171-172: "Since ... Luan River Basin", check the meaning of this sentence. It seems to be incomplete.

Response: we have revised the sentence “Since it is difficult to obtain actual evapotranspiration data and there are no long-term observation data from flux towers in the Luan River Basin, the water balance method was used to verify the accuracy of the simulated actual evapotranspiration.”

Author Response File: Author Response.pdf