Evaluation of Satellite-Derived Products for the Daily Average and Extreme Rainfall in the Mearim River Drainage Basin (Maranhão, Brazil)

Round 1

Reviewer 1 Report

My comments are attached.

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

06-October-2021

Dear

Ms. Tina Jiang

Section Managing Editor, MDPI Beijing

Remote Sensing

 

Thanks for the opportunity to participate in this evaluation. The Manuscript remotesensing-1402864entitled "Evaluation of satellite-derived products for the daily average and extreme rainfall in the Mearim River Basin (Maranhão, Brazil)." requires improvements. The paper is interesting, as it uses several satellite products to analyze their capability to represent rainfall and extreme indices over the Mearim river basin, however, I believe it is convenient to resolve several concerns throughout the paper before it is accepted. I have some comments that I expressed in detail. Therefore, I recommend a major revision.

 

As the paper does not have continuous line numbering, it is difficult to make guided observations in the paper. So my remarks are given for each subtopic of the document.

 

The abstract should have more synthesis work, it is very extensive.

Line 35. There is an unclosed parenthesis.

 

Introduction

Although the authors have made a correct formulation of the research problem, pointing out the difficulty of the density of stations and the opportunity provided by satellites, it is important to highlight previous studies on South America that have validated satellite data in other similar regions, which will provide greater relevance to their research.

 

Study area

The decimal number in the MDB area is unnecessary.

 

The percentages of the MDB biomes are not clear; they mention 54% for Amazonian biome, 46% for Cerrado, and 60% for MATOPIBA, the way it appears it seems to add up to 160%. It is important to improve this in the text; it is clear that they are two different kinds of percentages in the map.

 

Figure 1 needs to be improved. The authors barely mention in the text the box on the left of Figure 1, the maps on the right are not even mentioned; in my opinion, they are not contributing anything, or at least in the text, this is not clear.

 

Methods

 

Just a concern. They were considering that the gridBR data are only available from 1980 to 2013; why didn't the authors decide to work directly with the data from the stations with a more updated period of record? In my view, there are almost seven years of data (2014-2020) that would be interesting for this validation. And even more so if we consider that CHIRPS, MSWEP and PERSIAN have data up to the present.

 

How to ensure that the stations used by CHIRPS are not included in the validation with gridBR data? This is an important point to be careful about; otherwise, they would be using the same data twice to calculate their error statistics. https://data.chc.ucsb.edu/products/CHIRPS-2.0/diagnostics/chirps-n-stations_byCountry/Brazil/

What is the rationale for choosing only monthly mean and rx1day - maximum rainfall in 1 day (mm) to study extreme precipitation events recommended by the ETCCDI?

 

Authors change the font size from one paragraph to another; it is important to be consistent with journal standards.

 

Results

 

All figures need to be improved; their presentation is not quite adequate. Within the pixels in the basin (Figures 2-5), there are two in the northern part in white; is this an error in the data? Would it not be better to present only the pixels that are within the MDB?

 

The graphic scales in which Figures 6 and 7 have been classified have different class ranges; in my opinion, this makes the figures not comparable with each other, i.e., the CHIRPS data (Figure 6a) should all have the same class range, otherwise, it is not possible to recognize month to month differences.

Author Response

Please see the attachment. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thanks for authors' efforts for addressing all of my comments. I think the current version of manuscript is suitable for publication.

Reviewer 2 Report

The authors have responded to my concerns, and the paper satisfies the parameters for publication.

Nonetheless, I maintain my recommendation to present only the pixels within the basin in Figures 2 to 13, this would improve the quality of the final paper.