Deuterium excess in the atmospheric water vapour of a Mediterranean coastal wetland: regional vs. local signatures

Delattre, H.; Vallet-Coulomb, C.; Sonzogni, C.

doi:https://doi.org/10.5194/acp-15-10167-2015

Articles | Volume 15, issue 17

https://doi.org/10.5194/acp-15-10167-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-15-10167-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 15, issue 17

Research article

|

14 Sep 2015

Research article |

| 14 Sep 2015

Deuterium excess in the atmospheric water vapour of a Mediterranean coastal wetland: regional vs. local signatures

H. Delattre, C. Vallet-Coulomb, and C. Sonzogni

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Final revised paper (published on 14 Sep 2015)
Preprint (discussion started on 20 Jan 2015)

Interactive discussion

Status: closed

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

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RC C188: 'Review of "Deuterium excess in atmospheric water vapor of a Mediterranean coastal wetland: regional versus local signatures"', Anonymous Referee #1, 12 Feb 2015
RC C222: 'Review of "Deuterium excess in atmospheric water vapor of a Mediterranean coastal wetland: regional versus local signatures" by H. Delattre et al.', Anonymous Referee #2, 13 Feb 2015
RC C1521: 'Review', Anonymous Referee #3, 13 Apr 2015
AC C3331: 'Author responses', Christine Vallet-Coulomb, 08 Jun 2015
AC C3333: 'revised manuscript', Christine Vallet-Coulomb, 08 Jun 2015

Peer-review completion

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

AR by Christine Vallet-Coulomb on behalf of the Authors (08 Jun 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (08 Jun 2015) by Heini Wernli

RR by Anonymous Referee #1 (03 Jul 2015)

RR by Anonymous Referee #2 (10 Jul 2015)

Suggestions for revision or reasons for rejection

Review of "Deuterium excess in atmospheric water vapor of a Mediterranean coastal wetland: regional versus local signatures" (revised version) by H. Delattre et al.

In this revision, Delattre et al. have improved their manuscript. Some points are still unclear, as detailed below, but once these have been clarified, I think the paper can be published in ACP. The English writing could still be improved (which can be done by the ACP copyediting, I believe).

Specific comments:

- Lines 28, 341, Figures 5-7: Here the term "24-hour average values" (or something similar) is still used for the daily cycle analysis, which is not correct (it indicates that the data have been averaged over 24 hours, which is not the case).

- L 33 and other places: The term "the PBL vanishes" is a bit strange; I think "collapses" would be better.

- L 97-98: The abbreviations for d-excess should be harmonized.

- L 225: "Backward trajectories were started/initialized" instead of "Trajectories were parameterized to end up"

- L 227: It is still not clear what is meant by "oceanic source".

- L 274-295: The most important point here is not the normalization with respect to surface temperature, but the fact that it is the RH at the location where the water evaporated from the surface, and not at the measurement location, that is most closely related to the d-excess. As RH is not conserved during air mass transport (e.g., when the air parcel descends and is heated adiabatically, this changes RH), these are not the same. This should certainly be mentioned here.

- L 306-308: It is still not very clear how this classification is done. Please be a bit more specific by explicitly mentioning the geographic limits/coordinates of the different sectors and the time (backward along the trajectories) for which the classification is performed.

- L 330 "strong linear fits are evidenced" is not correct English

- L 396-412: It is a bit difficult to get the point of this paragraph, as the "dew formation" is only mentioned very late (in line 409). I'd note earlier that this is most likely the process leading to the observed gradual night-time depletion.

- Page 15: It confuses me that the equations are given in two very similar forms with the same meaning, but different notations. Moreover, the units of the symbols in equation (3) do not match. I'd suggest to remove equations (3) and (4); all the physics can be explained with equations (5) and (6).

- L 444: I don't understand the meaning of "until 1/q_1". The composition of the additional vapor is simply given by the intercept of the linear regression, isn't it?

- L 488-498: The description of these sensitivity analyses is too vague to be understandable. Which values have been used for the humidity and isotopic composition of the third component? What is meant by "remains compatible with a linear delta_v-1/q trend"? Doesn't this depend on the choice of the input values?

- L 508-510: I don't understand the meaning of this sentence.

- L 527: The global average of 10 refers to precipitation and not necessarily to water vapor. Please clarify.

- L 534-535: "or by local evaporation" instead of "either". What is meant by "spatial significances"?

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ED: Reconsider after major revisions (10 Jul 2015) by Heini Wernli

AR by Christine Vallet-Coulomb on behalf of the Authors (17 Aug 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 Aug 2015) by Heini Wernli

RR by Anonymous Referee #1 (26 Aug 2015)

ED: Publish as is (30 Aug 2015) by Heini Wernli

AR by Christine Vallet-Coulomb on behalf of the Authors (31 Aug 2015)

Short summary

Based on summer measurements of δ18O and δD in the atmospheric vapour of a Mediterranean coastal wetland exposed to high evaporation, this paper explores the main drivers of isotopic signal variability. After having classified the data according to the main regional air mass trajectories, average diurnal cycles are discussed with regards to the contribution of local evaporation to the ground level atmospheric vapour.