Precipitation stable isotopic signatures of tropical cyclones in Metropolitan Manila, Philippines, show significant negative isotopic excursions

Jackisch, Dominik; Yeo, Bi Xuan; Switzer, Adam D.; He, Shaoneng; Cantarero, Danica Linda M.; Siringan, Fernando P.; Goodkin, Nathalie F.

doi:https://doi.org/10.5194/nhess-22-213-2022

Articles | Volume 22, issue 1

https://doi.org/10.5194/nhess-22-213-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/nhess-22-213-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 22, issue 1

Research article

|

28 Jan 2022

Research article |

| 28 Jan 2022

Precipitation stable isotopic signatures of tropical cyclones in Metropolitan Manila, Philippines, show significant negative isotopic excursions

Dominik Jackisch, Bi Xuan Yeo, Adam D. Switzer, Shaoneng He, Danica Linda M. Cantarero, Fernando P. Siringan, and Nathalie F. Goodkin

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Final revised paper (published on 28 Jan 2022)
Supplement to the final revised paper
Preprint (discussion started on 02 Jan 2020)
Supplement to the preprint

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Referee's comments', Anonymous Referee #1, 18 Mar 2020
- AC1: 'Response to reviewer', Dominik Jackisch, 21 May 2020
RC2: 'Referee comments on Precipitation stable isotopic signatures of tropical cyclones in Metropolitan Manila, Philippines show significant negative isotopic excursions', Anonymous Referee #2, 01 Sep 2020
- AC2: 'Response to second reviewer', Dominik Jackisch, 12 Oct 2020
RC3: 'Review of “Precipitation stable isotopic signatures of tropical cyclones in Metropolitan Manila, Philippines show significant negative isotopic excursions“ by Jackisch et al.', Anonymous Referee #3, 08 Oct 2020
- AC3: 'Response to third reviewer', Dominik Jackisch, 19 Nov 2020

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (further review by editor and referees) (24 Mar 2021) by Paolo Tarolli

AR by Dominik Jackisch on behalf of the Authors (30 Apr 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (06 May 2021) by Paolo Tarolli

RR by Anonymous Referee #2 (10 May 2021)

RR by Anonymous Referee #4 (23 May 2021)

Suggestions for revision or reasons for rejection

General comment
In this manuscript the authors analysed the isotopic signature of precipitation from March 2014 to October 2015 in Metropolitan Manila, Philippines. They found that rain water collected during the landfall of some tropical cyclones had a progressive more depleted isotopic composition compared to rain water sampled during other rainfall events. Based on the data analyses, the authors found a significant relation between the daily isotopic composition of precipitation and the distance of the tropical cyclones from the sampling site.
I think the authors presented an interesting and valuable dataset of the isotopic composition of precipitation in Metropolitan Manila, Philippines. Despite the interesting presentation of the data collected during the landfall of some tropical cyclones, there is still a lack of a thorough analysis of the dataset, and particularly of the isotopic fractionation, which was speculated in section 4, and the meteorological characteristics (e.g., rainfall amount, air temperature etc.) that could influence the isotopic signature of precipitation during the landfall of tropical cyclones and the other rainfall events (please see the specific comments). There is a vast literature on these topics, and the authors could give a read to manuscripts which presented analyses of long time series of precipitation isotopic data (e.g., Guo et al., 2021). Furthermore, I think the authors should have accepted the valuable indications of the previous reviewer 3 because most of those comments were feasible to implement in the revised manuscript.
In addition, I think the current version of the manuscript still lacks some clarity. For example, the authors should clearly present and organize the research questions and the specific objectives. At the moment, the results are presented in only one section, but the authors could split them into 2-3 sections, and move the results of the statistical relations from the discussion to the proper section of the results.

Specific comments
L refers to the lines in the revised manuscript with the highlighted changes.
- L104-105: Please clearly formulate the research questions.
- L105-106: Please clearly report the specific objectives of this research study.
- Section 3: Why is there only one sub-section? The authors could organize the results based on the specific objectives and move here some of the results presented in the discussion (e.g., L348-353). In addition, I suggest to provide in this section the results for δ2H, and improve the section by the analysis of deuterium excess (Dansgaard, 1964) and the relations between the two isotopes, and between them and some meteorological characteristics (e.g., rainfall amount and air temperature).
- L241-243: Please expand the description of the results for Figure 5b.
- L247: I suggest to not use the term ‘proxy’ because stable isotopes cannot be assumed as representative of tropical cyclones. Please rephrase the title.
- L253-254: I have not found the hypothesis in the introduction. The authors should add it or clearly address it.
- L255-256: ‘isotopic fractionation’ was not assessed in the data analyses. I think the authors could significantly improve this manuscript by adding an analysis of deuterium excess, and of the dual-isotope plot (please see also my previous comments).
- L262 and L266-273: Please refer directly to the amount effect.
- L304-306: Please refer to a specific figure.
- L312-317: Rainfall amounts are not shown in Figure 2, and these sentences are not well supported by the results.
- L319: Why should we use stable isotopes of precipitation to detect or predict the landfall of tropical cyclones? It does not make sense to use isotopes in precipitation when satellite and radar data are available, particularly if the isotopic samples are collected at the daily timescale.
- L331-332: Rainfall amount data should be shown in the figures and not only on the supplementary material.
- L424-425: It is very unclear why the authors should suggest the sampling of stalagmites or trees, instead of precipitation. Why in the same location should we expect a different isotopic composition in precipitation and water used by vegetation (assuming that vegetation exploits mainly waters associated to tropical cyclones)?
- L435-436: Distance cannot be considered as a factor controlling/determining the isotopic signature of precipitation.
- Section 5 seems to propose again part of the discussion. I think the section should be more concise.
- Figure 2: Please add the time series of the main meteorological characteristics, i.e. daily rainfall and mean daily temperature measured at a local weather station.
- Figure 4: Please show rainfall amount as vertical bars.
- Figure 5 and 6: I suggest to connect the dots associated to the same tropical cyclone (this should help to understand the trajectories/direction of the tropical cyclones).

Technical corrections
- L24-25: ‘isotopic response to tropical cyclones’ is unclear. I suggest to replace with ‘isotopic variation related to tropical cyclones’.
- L104: I suggest to rephrase as follows: ‘if there is an isotopic variation in precipitation associated to the TC landfall’.
- L340: ‘causes’; I am not sure the authors could refer to a cause-effect relation.
- L349: Please put sample size, p-value and confidence interval between parentheses.
- L365-366: Please refer to Figure 6 and clearly identify the two outliers in the figure.
- L372: ‘a “false non-TC signal” of very negative rainfall unassociated with TC activity’ is quite difficult to understand. I suggest to rephrase.

References
Dansgaard W., 1964. Stable isotopes in precipitation. Tellus, 16(4), 436-468. DOI: 10.1111/j.2153-3490.1964.tb00181.x
Guo X., Gong X., Shi J., Guo J., Domínguez-Villar D., Lin Y., Wang H., Yuan D., 2021. Temporal variations and evaporation control effect of the stable isotope composition of precipitation in the subtropical monsoon climate region, Southwest China. Journal of Hydrology, 599, 126278. DOI: 10.1016/j.jhydrol.2021.126278

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ED: Reconsider after major revisions (further review by editor and referees) (23 May 2021) by Paolo Tarolli

AR by Dominik Jackisch on behalf of the Authors (27 Sep 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (01 Oct 2021) by Paolo Tarolli

RR by Anonymous Referee #4 (18 Oct 2021)

Suggestions for revision or reasons for rejection

I thank the authors for considering my comments. I think the manuscript has improved significantly compared to earlier versions. However, I still have some more specific comments that should be addressed before accepting the manuscript.

Specific comments
L refers to the lines in the revised manuscript with the highlighted changes.
- L208-209: Please move the sentence to Section 2.2.
- L210-212: Based on my experience, I would say that there is a high temporal variability in d-excess. Indeed, some samples seem to have a very evaporative signature (negative d-excess), whereas others have a d-excess even larger than 10.
- L232: I do not understand why the authors computed an average monthly rainfall. I think that the monthly rainfall amount (i.e., the sum) should be reported in Table 2, as well as in the following sentences (and in the data analysis).
- L239: Please report in the text what ‘r’ is. Does it indicate the Pearson correlation coefficient?
- L411-413: These results are not evident based only on Table 2. I suggest presenting a figure similar to Figure 4, but using monthly data. Please consider using monthly rainfall amounts, and not an average.
- L425-430: These lines belong to the Results. Please move them to the proper section.
- Conclusions: This section seems too long, and I do think the main conclusions were presented already between L506 and L522. My advice is to remove the remaining text (or to shorten it), especially all the sentences presenting again in great detail the results and part of the discussion.
- Figure 4: I suggest showing the samples associated to TCs with a different color.

Technical corrections
- L103: It should be ‘The main objectives of this research are the following:’
- L202 and L253: It is unclear what the authors mean with ‘rainfall intensive’.

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ED: Publish subject to minor revisions (review by editor) (12 Nov 2021) by Paolo Tarolli

AR by Dominik Jackisch on behalf of the Authors (01 Dec 2021) Author's response Author's tracked changes Manuscript

ED: Publish as is (04 Dec 2021) by Paolo Tarolli

AR by Dominik Jackisch on behalf of the Authors (14 Dec 2021) Manuscript

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Short summary

The Philippines is a nation very vulnerable to devastating typhoons. We investigate if stable isotopes of precipitation can be used to detect typhoon activities in the Philippines based on daily isotope measurements from Metropolitan Manila. We find that strong typhoons such as Rammasun, which occurred in July 2014, leave detectable isotopic signals in precipitation. Besides other factors, the distance of the typhoon to the sampling site plays a key role in influencing the signal.