Merging Satellite Products and Rain-Gauge Observations to Improve Hydrological Simulation: A Review
Round 1
Reviewer 1 Report
The topic addressed in the paper is interesting but extensive English editing is required to make the manuscript intelligible. I provide some detailed edit corrections in the attached file for the section “Introduction”. In various phrases some words (the subject and articles) are missing and the use of plural and singular verbs is inappropriate.
I suggest to resubmit the manuscript after an extensive English revision that is especially needed for a Review paper.
Comments for author File: 
Comments.pdf
Author Response
The authors would like to thank for reviewing this manuscrpit.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper reviews several methods for the merging of different precipitation observations from gauge, satellites and models and its impact on hydrological modelling.
The paper is clear and well written even if there are now and then some typos and missing words (in the minor comments the authors can find a few reported, but I suggest to carefully go throughout the manuscript).
I would like to ask the Authors to add a personal perspective in the conclusion section. What is the next step that should be done by the hydrological or meteorological communities to foster this topic? I think this should be the most important goal of writing a review.
Please, complete the literature with these two papers that should be useful and add some information.
- Massari, C., Brocca, L., Pellarin, T., Abramowitz, G., Filippucci, P., Ciabatta, L., Maggioni, V., Kerr, Y., Fernández-Prieto, D. (2020). A daily/25km short-latency rainfall product for data scarce regions based on the integration of the GPM IMERG Early Run with multiple satellite soil moisture products. Hydrology and Earth System Sciences, 24, 2687–2710, doi:10.5194/hess-24-2687-2020. https://doi.org/10.5194/hess-24-2687-2020
- Brocca, L., Massari, C., Pellarin, T., Filippucci, P., Ciabatta, L., Camici, S., Kerr, Y.H., Fernández-Prieto, D. (2020). River flow prediction in data scarce regions: soil moisture integrated satellite rainfall products outperform rain gauge observations in West Africa. Scientific Reports, 10, 12517, doi:10.1038/s41598-020-69343-x. https://doi.org/10.1038/s41598-020-69343-x
- Bishop, C. H. and Abramowitz, G.: Climate model dependence and the replicate Earth paradigm, Clim. Dynam., 41, 885–900, 2013
- Crow, W. T., Huffman, G. J., Bindlish, R. and Jackson, T. J.: Improving Satellite-Based Rainfall Accumulation Estimates Using Spaceborne Surface Soil Moisture Retrievals, J. Hydrometeorol., 10, 199–212, https://doi.org/10.1175/2008JHM986.1, 2009.
- Massari, C., Crow, W., Brocca, L. (2017). An assessment of the accuracy of global rainfall estimates without ground-based observations. Hydrology and Earth System Sciences, 21, 4347-4361, doi:10.5194/hess-21-4347-2017. http://dx.doi.org/10.5194/hess-21-4347-2017
Minor comments
Lines 44-46. Which is the problem the authors are referring to? Please rephrase the sentence. Moreover I think “to” is missing after interpolation.
Line 61. Please change P estimation with P estimates
Line 72. Warm orographic what? Rainfall, precipitation?
Line 99. add “of” after “review”
Line 103. Add “of” after “aspects”
Line 113. REMOVE .)
Author Response
The authors would like to thank for reviewing this manuscrpit.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The revised version of the manuscript was improved especially in section 1 and 2, but detailed English corrections are still needed.
Some edit corrections are provided in the attached file.
I agree with the discussion proposed by the authors about the importance of rain gauge observations to derive reliable estimations of precipitation measurements. In this direction, I suggest to introduce a paragraph (in the Introduction section) about the importance of the correction of precipitation measurements biases for precipitation gauges. In particular, precipitation gauges are affected by instrumental and environmental biases. Wind is the main environmental source of measurement bias and the evidence of the wind-induced undercatch is clearly explained in the following papers:
Jevons, W. S. (1861). On the deficiency of rain in an elevated rain-gauge, as caused by wind. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 21(4). Available from https://doi.org/10.1016/0016-0032(62)90997-3 .
Cauteruccio, A., Brambilla, E., Stagnaro, M., Lanza, L.G. and D. Rocchi (2021). Experimental evidence of the wind-induced bias of precipitation gauges using Particle Image Velocimetry and particle tracking in the wind tunnel. J. of Hydrol., 600, 126690. https://doi.org/10.1016/j.jhydrol.2021.126690.
Folland, C. K. (1988). Numerical models of the rain gauge exposure problem, field experiments and an improved collector design. Quarterly Journal of the Royal Meteorological Society, 114(484), 1485-1516. Available from https://doi.org/10.1002/qj.49711448407 .
The description of the instrumental biases and of the calibration procedure to correct this biases is described in the following book chapter and in the references therein.
Cauteruccio A., Colli M., Stagnaro M., Lanza L.G. and E. Vuerich (2021). In situ precipitation measurements, p. 359 – 400. In: Foken T. (ed.), Springer Handbook of Atmospheric Measurements. Springer Nature, Switzerland, ISBN 978-3-030-52170-7, e-ISBN 978-3-030-52171-4, pp. 1740. https://doi.org/10.1007/978-3-030-52171-4_12
Marsalek, J. (1981). Calibration of the tipping-bucket raingage. Journal of Hydrology, 53 (3-4), 343-354. Available from https://doi.org/10.1016/0022-1694(81)90010-X .
Sevruk, B. (1982). Methods of correction for systematic error in point precipitation measurement for operational use. Tech. Rep. WMO N. 589, OHR N. 21. ISBN 978-92-63-10589-9.
I suggest to introduce an appropriate discussion also in the Conclusion section.
Comments for author File: Comments.pdf
Author Response
The authors of this manuscript would like to thank for your time valuable comments and suggestions.
Author Response File: Author Response.docx
