Sensitivity of the Penman–Monteith Reference Evapotranspiration Equation to Meteorological Variables for Puerto Rico
Round 1
Reviewer 1 Report (Previous Reviewer 2)
Dear authors
The submitted manuscript is very interesting to the readers of Hydrology. However, some minor revision is needed and some aspects must be improved such as:
Lines 45 to 48: Figure 1 caption should be improved; units should be presented in the International System of Units (IS) and should not include references. The figures 1 and 2 must be presented in the material and methods
Lines 67: According to Allen et al. (1998) must be used crop evapotranspiration (ETc) and not ETp
Lines 139 to 141 mention that: “" Rainfall has a bimodal distribution with high rainfall in May-early June and late July-November." It must be shown average annual precipitation.
In the discussion, it is important to analyse other studies, verifying if the P-M equation shows the same sensitivity to the analysed variables in others latitude.
Author Response
Please see attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report (Previous Reviewer 3)
Dear Authors,
Sensitivity of the Penman-Monteith Reference Evapotranspiration Equation to Meteorological Variables for Puerto Rico
This paper examines the sensitivity of the American Society of Civil Engineers standardized reference evapotranspiration (ETo) equation to five meteorological variables derived from GOES-PRWEB data for Puerto Rico was determined. The author used dynamically downscaled climate projections from two general circulation models (CNRM and CESM). The authors showed that the sensitivity coefficients for RHmean dominates the sensitivity of ETo throughout most of the island even more so that the SCs for Rs and Tmax. And showed that both models project a 5.6% average increase in annual ETo between the two periods mainly because of projected increases in Tmax and Tmin and a decrease in RHmean. The article deals with an important topic that can be used to improve public policies. After the first version was submitted, the authors carried out an extensive revision of the document, showing significant improvements. This way, However, this manuscript requires an minor revision yet. I suggest a minor revision.
The authors greatly improved the introduction and the goals it achieved.
You just need to improve the abstract, you need to clarify the purpose of this article. Just as a conclusion is not clearly presented to the readers.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
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.
Round 1
Reviewer 1 Report
1. To justify the soundness of using climate model data to compute reference ET (RET), it is suggested that meteorological data from a few existing weather stations (if possible) be selected to compute RET to compare with that of the climate models. Quantities such as annual total, daily RET time series and scatter plot can be compared to justify if RET of the climate model can properly resemble that of the weather stations.
2. The paper states: “Both models project a 5.6% average increase in annual ETo between the two periods mainly as a result of projected increases in Tmax and Tmin and a decrease in RHmean”. To show how ETo changes over time from climate change (e.g., trend, magnitude of fluctuation), it is suggested that annual total ETo from selected representative stations or whole region is presented.
3. The period from 1985 to 2005 is what already happened. Can the simulation results be somehow justified with the existing meteorological data observed (if any)?
4. “The ASCE standardized reference evapotranspiration equation” published by ASCE (American Society of Civil Engineers) EWRI (Environmental and Water Resources Institute) Task Committee on Standardization of Reference Evapotranspiration, 2005 lays out a platform in computing ETo in various ways (hourly or more frequent humidity data, versus RHmax, RHmin, Tmax, Tmin, versus RHmean, Tmax, Tmin, etc.) and time steps (daily, hourly, etc.). This study has demonstrated a methodology in examining the sensitivity and applicability of using the right meteorological parameter sets and approaches in computing ETo for specific situations.
5. As a minor observation, on Line 362 “Comparison of Figures 1a and 1b shows two distinct areas of high rainfall”, where are Figures 1a and 1b? They can not be seen in the paper.
Reviewer 2 Report
Dear authors
The submitted manuscript is very interesting to the readers of Hydrology. However, some minor revision is needed and some aspects must be improved such as:
Lines 45 to 48: Figure 1 caption should be improved; units should be presented in the International System of Units (IS) and should not include references. The figures 1 and 2 must be presented in the material and methods
Lines 67: According to Allen et al. (1998) must be used crop evapotranspiration (ETc) and not ETp
Lines 139 to 141 mention that: “" Rainfall has a bimodal distribution with high rainfall in May-early June and late July-November." It must be shown average annual precipitation.
In the discussion, it is important to analyse other studies, verifying if the P-M equation shows the same sensitivity to the analysed variables in others latitude.
Reviewer 3 Report
Dear Authors,
Sensitivity of the Penman-Monteith Reference Evapotranspiration Equation to Meteorological Variables for Puerto Rico
This paper examines the sensitivity of the American Society of Civil Engineers standardized reference evapotranspiration (ETo) equation to five meteorological variables derived from GOES-PRWEB data for Puerto Rico was determined. The author used dynamically downscaled climate projections from two general circulation models (CNRM and CESM). The authors showed that the sensitivity coefficients for RHmean dominates the sensitivity of ETo throughout most of the island even more so that the SCs for Rs and Tmax. And showed that both models project a 5.6% average increase in annual ETo between the two periods mainly because of projected increases in Tmax and Tmin and a decrease in RHmean. The article deals with an important topic that can be used to improve public policies. However, this manuscript requires an important revision. The authors need to better discuss the results they found. These and other issues should be considered/clarified prior to acceptance. I suggest a major revision.
Introduction
The abstract needs to clarify the purpose of this article.
The introduction needs more details of the methodology used. If it was applied in other studies, or compared with the state of the art.
The introduction also needs to clarify the importance of this study, justifying the reason for this research
There is no connection between the paragraphs in introduction.
The objectives are not well described. What are the secondary objectives?
Results and Discussion
In general, the results are well presented and demonstrate the importance of the study. However, a better discussion with the factors that contribute these results. And the effects that can occur to lead to these results.
Conclusion
You need to conclusion better your work. And it does not answer all the proposed objectives. It needs to be improved.
