Spatio-Temporal Assessment of Satellite Estimates and Gauge-Based Rainfall Products in Northern Part of Egypt

Round 1

Reviewer 1 Report

• The performance of 12 rainfall products in northern Egypt was studied in this paper. The main poblems of the paper are as follows.

  1.Abstract should provide data to supportthe summary conclusion.

  2.The conclusion should correspond to the previous research content.

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Author Response

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Reviewer 2 Report

The manuscript developed an extensive and comparative analysis of several rainfall products available in the Egypt region. The relevance of this kind of study serves to highlight the meaninfulness of every rainfall product when there are installed validation points for checking the truth in field. The Egipt region has the difficult feature that rain is the missing event (really few mm by year) for being detected by rainfall product and remote sensing even for being validated by true field mesurents.

One suggestion can be improve the present visualisation results from Figure 3, just by starting the plot in july and finishing it by june, wich will left the maximum at the middle.

Author Response

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Reviewer 3 Report

This paper evaluated the performance of 12 rainfall products for 8 locations in the Northern part of Egypt. The rainfall products are compared with the rain gauges at monthly and annually time scales. Overall, I find this study suffers from several technical issues (see below).

Major Comments:

1. The author only used 8 rain gauges and compared the rainfall products at monthly and annual time scales. From both spatial and temporal aspects, it’s too coarse to say it as “spatio-temporal assessment”.

2. It is hard to understand why the author chose to aggregate daily rainfall products, instead of evaluating the products at daily scales. The only reason given is in lines 189 to 190, ‘’ As mentioned in literature, daily timescale was ignored in this research as a result of low performance of RP [47]. This is due to a measurement time difference between the ground stations and the RP.” This reason is not convincing, the 12 RPs are not specific to a time of the day. If a RP is daily product, it represents the daily accumulative, or average, rainfall amount.

3. The annual aggregation is especially problematic. For RPs with short temporal coverages, e.g., TRMM, RFE and CMORPH. The annual aggregation results in small data sample size (< 30), which is not suitable for statistical evaluation (sections 3.1 and 3.2). All the metrics (in table 2) should be calculated using sufficiently large samples.

4. Another issue is the RPs have very different temporal coverages. This makes the content 3.1 and 3.2 rather meaningless. In other words, it does not make sense to compare the 18-year annual rainfall distribution from CMORPH to the 128-year distribution from GPCC; they essentially represent two different climates.

Author Response

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Reviewer 4 Report

General Comments

The research manuscript intent to investigate the performance of several RP across Northern Egypt for annual and monthly rainfall. The review on the RP (sub-section 1.1 to sub-section 1.4) in the introduction is excellent and commendable, as it will peak the interest from a lot of researcher and reader. However, the objective is weak, as the annual and monthly rainfall assessment too general and does not give any significant results for the climate assessment. The research can be extended to various other specific indices such as extreme rainfall, bioclimatic indices etc., which are lowly investigated. There is no relation made on the annual/monthly rainfall assessment to large scale climate phenomena or any other change in other environmental state (flood, drought etc). The results are too general and the author is advisable to prepare the spatial mapping of the study area rainfall pattern based on the selected or best RP that can simulate the local rainfall? At this point, I will reject the manuscript. My other specific comments are provided as below.

Specific comments

Abstract

·       Line 16: rainfall products > RP. Please use the abbreviation after it as mentioned for the first time. Make correction for the rest of the manuscript.

·       Line 17: annually > annual

·       Please briefly specify and explain how the evaluation process and methodology was conducted in the abstract.

Keywords

·       Please provide at least five relevant keywords

1.0 Introduction

·       Line 23: Chirps > CHIRPS

2.2 Evaluation rainfall products

·       Line 169: Can you give justification for the usage of more than 15 years’ recorded data?

·       Table 1: Please give the full name of the rainfall product.

2.4 Statistical evaluation of rainfall products

·       Line 187: Why did the zero rainfall on the months of June, July and August is not being evaluated? Zero rainfall means no rainfall occurrence. Do you mean missing data here?

·       Line 190-191: The justification that daily rainfall data was ignored due to time difference between ground station and RP does not make any sense.

·       Table 2: Please justify the acceptable range used in the manuscript for each statistical index.

3.1 Annual rainfall distribution

·       Figure 2: The background line can be remove (Make similar revision for all figure). The boxplot color bar/line can be make consistent for each RP. Please consider the usage of Probability Density Function (PDF) Plot or Taylor diagram to compare the performance of the RP.

3.2 Evaluation of annual rainfall products

·       Line 240-242: Please use italic/bold words or asterisk symbol (*) instead of color shade in Table 3. Make similar revision for other figure/table.

3.3 Monthly rainfall distribution

·       What do you mean by “value” in this section? Please be more specific, for example, “monthly rainfall” etc.

·       Figure 3: please consider using Probability Density Function (PDF) Plot or Taylor diagram to compare the performance of the RP.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

No further comments

Author Response

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Reviewer 4 Report

General Comments

The research manuscript intent to investigate the performance of several RP across Northern Egypt for annual and monthly rainfall. The manuscript has been substantially improved by the authors following the first review. However, the quality of the figure is low. There is improvement needed to make the figure more presentable and clear. My other specific comments are provided as below.

Specific comments

1.0 Introduction

·       Line 154. Please list the name of the RP that you used for comparison in the study

·       Line 156: Please list the name of the statistical indicator used in the study.

·       Line 154-158: This sentence can be separated into two.

2.2 Evaluation rainfall products

·       Table 1: Remove the repetitive abbreviation under heading “Rainfall product”. The heading for “abbreviation” is already there.

·       Table 1: In the temporal coverage, please revise “1983-now”. Do you mean 1983-2022? Please be specific as it is confusing.

2.4 Statistical evaluation of rainfall products

·       Line 202: It is difficult to understand what do you mean by “time difference” here. It is confusing. Please be more clear. Do you mean different start/end year? Or is there a lag time difference here? Or do you mean time zone difference? I just don’t understand. Very confusing.

·       Line 203: “In addition, CRU and GPCC data sets are monthly timescale.” > “In addition, CRU and GPCC data sets are only available for monthly timescale, therefore, comparative assessment for daily timescale will be unable to be undertaken with other RP”. Please be more clear.

3.1 Annual rainfall distribution

·       Figure 2: Remove the outer box of the figure, and background line of the boxplot. Remove the outer box for other figure in the manuscript.

·       Figure 3: This is a line chart, not a PDF. I might be wrong, maybe you’re using different way of constructing PDF. Please refer to this journal for an example. https://link.springer.com/article/10.1007/s00704-022-04007-6

3.3 Monthly rainfall distribution

·       Figure 4: One legend is sufficient to reflect all the station. Similar revision can be done for Figure 5.

·       Figure 6: Remove the outer box for each map. It is advisable to use one color with different color intensity for the map.

Comments for author File: Comments.pdf

Author Response

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