Forcing the Penman-Montheith Formulation with Humidity, Radiation, and Wind Speed Taken from Reanalyses, for Hydrologic Modeling

Round 1

Reviewer 1 Report

The study describes an evaluation of hydrological modeling using input from 4 reanalysis datasets. After reading the manuscript, while I am not aware of the improvement of model results and hard to get the main key points. Please see the following comments:

1.      The title “Penman-Montheith formulation” indicates this study is mainly about evapotranspiration. While the results cannot show that Penman-Montheith formulation is better than the temperature-based Hamon method, although Penman-Montheith formulation requires much more input. Generally, evapotranspiration is shortened as “ET” not “E”. The ET simulation using reanalysis datasets should be compared to observed ET. The authors only show ET relationships with other climate variables (Figure 5), which is not the objective of the study. Even with the corrected of HRW fields, I cannot clearly see the improvement of simulation.

2.      Figures 1 and 2 need to be improved, such that can be easily understood. Add legend and DEM in Figure 1. Try to fully spell the words in Figure 2, what is the meaning “p”?

3.      Line 75, use “study” instead of “manuscript”

4.      “Without formally exploring this idea, Auerbach et al. [7] suggested exploiting the HRW fields from the CFSR reanalysis in order to simulate hydrologic processes on more mechanistic grounds.” in Lines 79-81, this statement should be your conclusion, for which more figures and evidence should be given to get the conclusion.

5.      Line 91 “nivopluvial” should be “nivo-pluvial”, you may want to explain its meaning a little bit.

6.      The columns of “ID” and “Meteorological station ID” are not necessary.

7.      Line 117-120, why these four reanalysis datasets are selected, any reason? In addition, you can easily get the surface temperature from these datasets, however, observed temperature is used for the following simulations. I this study want to evaluate the feasibility and applicability of reanalysis dataset in the hydrological model, temperature from reanalysis should be used for in-depth comparisons.

8.      Some variables in Table 2 are not clear to me. Is the correction parameter “as” a free parameter? Better explain “?????”. Is “Qh” the interflow, which is the same as “Qint”?

9.      Please add a table to show the optimized values of all the parameters.

10.   For the Correction of simulated HRW fields, why Eq (10a) differs from Eq(10b) and EQ(10c)? My question is why not use the same logic, use a ratio to correct humidity in Eq (10a)?

11.    Figure 4, the better performance in hydrologic modeling using corrected HRW fields is not clear or significant. Are all the simulations using the same optimized free parameters?

12.   Figure 5 does not show the well-simulated ET using the HRW fields.

13.   Line 333, “The hydrologic response is known sensible to the selection of a given E0 formulation” is not demonstrated based on the results.

Author Response

We would like to thank Reviewer 1 for his constructive revision. We believe the resulting modifications significanlty improve the manuscript. See full response to comments in the uploaded PDF file.

Author Response File: Author Response.pdf

Reviewer 2 Report

I really enjoyed reading the manuscript.  The motivation of the study is clear and the results are well presented.  I particularly enjoyed the  discussion section where the authors also focus on the limitations of the study.   Overall I liked the manuscript in its current form and am happy to approve it. 

Author Response

We would like to thank Reviewer 2 for his time and positive comments.

Reviewer 3 Report

Great study and the manuscript is well written. The results seem complex to read and the discussion needs some improvement by comparing the presented results with the past studies. Wind should be replaced by wind speed throughout the manuscript. The manuscript may be edited for grammar and spellings.

Comments for author File: Comments.pdf

Author Response

We would like to thank Reviewer 3 for his constructive commments. A full response is provided in the uploaded PDF file.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

My comments are clearly and carefully responded.   Thanks for the work.