Scale-Dependent Reliability of Projected Rainfalls over Bangladesh with the PRECIS Model
Round 1
Reviewer 1 Report
The paper evaluated the reliability of projected rainfall from PRECIS model for Bangladesh. The paper used various statistical methods to achieve the goal, and found that the model could capture the overall spatial pattern of mean annual and monthly rainfalls very well, but failed to predict the inter-annual variability and extremes. The results are interesting to readers concerning the applicability of PRECIS model in South Asia. However, the authors used the rainfall observations from BMD at 28 stations, which raises the concern that the observations (the point observation) and the modelled rainfall (areal mean) are mismatching. In addition, whether or not the observed rainfalls are homogenised is not clear. Therefore, the authors need to clarify the observations and design more appropriate way to compare the observed and modelled rainfall.
Minor points:
Ln 250: 'lower' should be 'low'. Ln 337: 'gage' should be 'gauge'.Author Response
The paper evaluated the reliability of projected rainfall from PRECIS model for Bangladesh. The paper used various statistical methods to achieve the goal, and found that the model could capture the overall spatial pattern of mean annual and monthly rainfalls very well, but failed to predict the inter-annual variability and extremes. The results are interesting to readers concerning the applicability of PRECIS model in South Asia.
Point 1: However, the authors used the rainfall observations from BMD at 28 stations, which raises the concern that the observations (the point observation) and the modelled rainfall (areal mean) are mismatching.
Response 1: We thank the reviewer for his concern. However, we humbly would like to point out that we have followed the literature and the papers previously worked on point observations of rainfall versus areal modelled rainfall (e.g., PRECIS, RegCM etc.) on Bangladesh are as follows:
Islam, M.N. Rainfall and Temperature Scenario for Bangladesh. Open Atmos. Sci. J. 2009, 3, 93–103. Islam, M.N.; Rafiuddin, M.; Ahmed, A.U.; Kolli, R.K. Calibration of PRECIS in employing future scenarios in Bangladesh. J. Climatol. 2008, 28, 617–628. Rahman, M.M.; Islam, M.N.; Ahmed, A.U.; Georgi, F. Rainfall and temperature scenarios for Bangladesh for the middle of 21st century using RegCM. Earth Syst. Sci. 2012, 121, 287–295.Point 2: In addition, whether or not the observed rainfalls are homogenised is not clear. Therefore, the authors need to clarify the observations and design more appropriate way to compare the observed and modelled rainfall.
Response 2: Reply: Existing Literature on homogeneity of all point observational stations has been briefly reviewed in the revision (Line 222-226) as follows:
Daily rainfall monitored at all 28 gauges of BMD successfully passed the homogeneity test as has been reported in [32–35]. Notably, for all 28 BMD stations Khan et al. [34] found almost straight lines with no breakpoint in the double mass curves and Mahmud et al. [35] observed homogeneity using Standard Normal Homogeneity test, Von Neumann Ratio test, Buishand Range test and Pettitt test.
Minor points:
Point 3: Ln 250: 'lower' should be 'low'.
Response 3: Corrected accordingly.
Point 4: Ln 337: 'gage' should be 'gauge'.
Response 4: Corrected accordingly.
Reviewer 2 Report
Evaluation of the manuscript entitled:
Scale-dependent reliability of projected rainfalls over Bangladesh with the PRECIS model
By M. Mondal, Mostofa Sakib and Sara Nowreen
This manuscript presents the results of an application of the regional climate model PRECIS in simulating annual, monthly and extreme rainfalls over Bangladesh by using statistical techniques. However, this manuscript is not well written and organized and the content of the manuscript is difficult to understand.
The manuscript has serious drawbacks:
Major comments
Abstract should be rewritten. In the abstract with 200 words maximum to be given (See journal directions) the question addressed and highlight the purpose of the study, methods, results and indicate the main conclusion.
The introduction is so large. It needs to shorten and be more comprehensive. It should define the purpose of the work and its significance. The current state of the research field should be reviewed carefully and should be shown the new that the study brings.
Authors needs to develop a clear logic on why the topic of this article is necessary based on the findings of the previous works that addressed the similar issue. Now, I don't find such a clear logical flow in the introduction.
Must be clear model description and methodology (statistics that were used) and very little information is provided about the rainfall data were used.
The results should be better presented. The paper is generally poorly written. An extensive editing is needed.
It would be helpful to the reader of the study to show the positions of the met. stations
Based on the serious concerns on the quality of this manuscript, I do not recommend that this manuscript can be accepted in the present form.
Author Response
Scale-dependent reliability of projected rainfalls over Bangladesh with the PRECIS model
By M. Mondal, Mostofa Sakib and Sara Nowreen
This manuscript presents the results of an application of the regional climate model PRECIS in simulating annual, monthly and extreme rainfalls over Bangladesh by using statistical techniques.
Point 1: However, this manuscript is not well written and organized and the content of the manuscript is difficult to understand.
The manuscript has serious drawbacks:
Response 1: Authors have tried to reorganize the contents of the manuscript to make it easily understandable for the reviewer (and readers).
Major comments
Point 2: Abstract should be rewritten. In the abstract with 200 words maximum to be given (See journal directions) the question addressed and highlight the purpose of the study, methods, results and indicate the main conclusion.
Response 2: As suggested, the abstract is modified where question is addressed in Line 13-14, the purpose of the study is highlighted in Line 14-15, methods can be found in Line 16-18, results are mentioned in Line 18-22 and the main conclusion is indicated in Line 22-23.
Point 3: The introduction is so large. It needs to shorten and be more comprehensive. It should define the purpose of the work and its significance. The current state of the research field should be reviewed carefully and should be shown the new that the study brings.
Response 3: As suggested, introduction is shortened and made concise. The revised introduction now clearly defines the purpose of the study.
Current state of the research field on PRECIS model is described in a new section (i.e., Section 2).
The main novel contribution that the study makes is mentioned in Line 57-64 as described below:
It is hoped that the performance evaluation of the PRECIS model in simulating the rainfall over Bangladesh will guide a number of vulnerability studies that are currently being conducted for the country using projected climate data (for example, the Ecosystem Services for Poverty Alleviation [ESPA] project funded by the UK's Department for International Development [DfID], and the DEltas, vulnerability and Climate Change: Migration and Adaptation [DECCMA] project funded jointly by DfID and the Canada's International Development Research Center [IDRC]; both ESPA and DECCMA projects are using RCM projection).
Point 4: Authors needs to develop a clear logic on why the topic of this article is necessary based on the findings of the previous works that addressed the similar issue. Now, I don't find such a clear logical flow in the introduction.
Response 4: Previous works did not rigorously check the performance between observed and modelled rainfall the way our study presented. The focuses of previous rainfall works on PRECIS for Bangladesh were different. In particular, in those works calibration of PRECIS was done using RegCM and future scenarios were developed using PRECIS projections. In fact, previous authors indicated the need of a rigorous study like ours in their recommendations, which motivated us to conduct this study.
Point 5: Must be clear model description and methodology (statistics that were used) and very little information is provided about the rainfall data were used.
Response 5: PRECIS is a well-known RCM model, hence, a brief description is provided in Line 42-44 referencing to relevant literatures due to space constraint. Since the reviewer asked, a detail description is provided in supplementary section S1.
Statistical methods mentioned in Line 144-146 are spatial-pattern correlation, temporal correlation, root mean square difference (RMSD) and mean absolute difference (MAD). In addition, Student’s t-test and Probability density functions (PDFs) were mentioned in Line 157-159.
Detail on observed rainfall data are given in Line 176-179 and simulated rainfall data are given in Line 161-165 of Section 3.
Point 6: The results should be better presented. The paper is generally poorly written. An extensive editing is needed.
Response 6: Authors have tried to reorganize the contents of the manuscript to make it easily understandable for readers.
Point 7: It would be helpful to the reader of the study to show the positions of the met. stations
Response 7: Black cross in Figure 1 (left) denotes the location of the observed meteorological (i.e., rainfall) stations. This description is already mentioned in Figure 1.
Based on the serious concerns on the quality of this manuscript, I do not recommend that this manuscript can be accepted in the present form.
Reviewer 3 Report
Observations and Comments
Abstract
OK
IntroductionLine 60: “rainfalls in all the months would increase in future” should be - rainfalls in all the months would increase in the future
Study Area, Methodology and DataOk
Results and discussionLine 196: “probability density functions (pdfs)” – not captured and explained in the methodology section
I suggest adding a simple scatter plot to show the relationships between simulated and observed rainfall
ConclusionOK
Author Response
Abstract: OK
Introduction
Point 1:
Line 60: “rainfalls in all the months would increase in future” should be - rainfalls in all the months would increase in the future
Response 1: Corrected accordingly.
Study Area, Methodology and Data: Ok
Results and discussion
Point 2:
Line 196: “probability density functions (pdfs)” – not captured and explained in the methodology section
Response 2: PDF is included in the methodology section.
Point 3:
I suggest adding a simple scatter plot to show the relationships between simulated and observed rainfall
Response 3: As suggested scatter plot is included as denoted as supplementary Figure S1.
Conclusion: OK
Round 2
Reviewer 1 Report
The authors have appropriately responded to my concerns, and improve the manuscript accordingly. It can be accepted.
Author Response
Dear Reviewer,
Thank you very much.
Regards,
Sara
Reviewer 2 Report
Indeed, the manuscript has improved but I think the authors should respond in the next comment.
In the text of manuscript and supplementary figures are mentioned many names of met. stations (Dinajpur, Mymensingh, Rangpur, Patuakhali, Sylhet etc). The black crosses in Figure 1 (left) denotes the location of the observed rainfall stations but that's not enough. Crosses must be replaced with numbers and link to the names in table S1.
Author Response
Indeed, the manuscript has improved but I think the authors should respond in the next comment.
In the text of manuscript and supplementary figures are mentioned many names of met. stations (Dinajpur, Mymensingh, Rangpur, Patuakhali, Sylhet etc). The black crosses in Figure 1 (left) denotes the location of the observed rainfall stations but that's not enough. Crosses must be replaced with numbers and link to the names in table S1.
Reply:
As suggested, Figure 1 is modified, where meteorological station names are denoted with numbers and linked with Supplementary Table S1. Accordingly, the caption of Figure 1 is edited in the revision (Line 132-133).
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.
