Sensitivity of potential evapotranspiration to changes in climate variables for different Australian climatic zones

Guo, Danlu; Westra, Seth; Maier, Holger R.

doi:https://doi.org/10.5194/hess-21-2107-2017

Articles | Volume 21, issue 4

https://doi.org/10.5194/hess-21-2107-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/hess-21-2107-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 21, issue 4

Research article

|

19 Apr 2017

Research article |

| 19 Apr 2017

Sensitivity of potential evapotranspiration to changes in climate variables for different Australian climatic zones

Danlu Guo, Seth Westra, and Holger R. Maier

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Final revised paper (published on 19 Apr 2017)
Preprint (discussion started on 19 Sep 2016)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'review of HESS-2016-441', Giovanni Ravazzani, 28 Oct 2016
- AC1: 'Authors' Responses to Reviewer #1', Danlu Guo, 07 Dec 2016
RC2: 'Peer Review for the manuscript "Sensitivity of potential evapotranspiration to changes in climate variables for different climatic zones"', Anonymous Referee #2, 21 Nov 2016
- AC4: 'Authors' Responses to Reviewer #2', Danlu Guo, 07 Dec 2016
RC3: 'Comments on Guo et al. paper', Anonymous Referee #3, 22 Nov 2016
- AC3: 'Authors' Responses to Reviewer #3', Danlu Guo, 07 Dec 2016
AC2: 'Authors' Responses to Reviewer #2', Danlu Guo, 07 Dec 2016

Peer-review completion

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

ED: Reconsider after major revisions (further review by Editor and Referees) (20 Dec 2016) by Nunzio Romano

AR by Danlu Guo on behalf of the Authors (22 Dec 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (28 Dec 2016) by Nunzio Romano

RR by Anonymous Referee #3 (27 Jan 2017)

RR by Anonymous Referee #4 (28 Feb 2017)

Suggestions for revision or reasons for rejection

Review of “Sensitivity of potential evapotranspiration to changes in climate variables for different Australian climatic zones”

Guo and colleagues use a scenario-neutral approach to identify the sensitivity of PET possible changes in temperature, relative humidity, solar radiation and wind speed, and thereby focus on the role of the baseline climate conditions. Understanding sensitivities of hydrologic changes from a scenario neutral perspective appeals to me, and I think the presented case study is relevant for HESS.

The authors did a decent job in addressing the concerns of 3 reviewers that have been brought up in the initial review round.

In general the paper is generally Ok written. However, I have a couple of minor suggestions that will hopefully be addressed (see list below). In addition to these minor suggestions, I have several one significant concern that need to be clarified before I can recommend publishing this article:

All results are based on sensitivities with the unit %. This is very strange, as sensitivity should be defined “as change per unit of change in the driver”. E.g. precipitation elasticity of runoff has units “%/%” or streamflow sensitivity to water storage changes can have the unit “%/mm” (since total storage is often unknown). What you seem to present instead are “magnitude of changes derived from sensitivities and typical/expected rates of changes in drivers”. This means that (i) either you have to change your analyses, or you have to change the terminology of your paper (e.g. that you talk about expected magnitudes of change).

Suggestions

Line 11: “anthropogenic” can potentially be removed; the method you use is independent of the cause of climate change, and may thus also be very relevant for other things, such as understanding the impacts of climate variability

Line 32: “fluxes” seems redundant

Lines 34: Note that the 62% is not representative for the part of the land-surface where ET is a more dominant flux than runoff. The fraction of land-surface where evaporation exceeds runoff is actually much larger. (e.g see https://younghydrologicsociety.files.wordpress.com/2016/07/article_1.pdf).

Line 31-39: it would be good to also acknowledge that changing C02 levels will alter ET via other routes (e.g. CO2 fertilizations, changing water use efficiency).

Line 47: “the impact on catchment yield” it is unclear what “yield” you refer to…

Lines 110-115: is it worth mentioning that there is an appendix section for the paper?

Line 134-137: the units seem inconsistent. For radiation you choose to represent a flux by energy amount per unit of time, while for the precipitation flux you ignore in the unit that this is also “per unit of time”. My suggestion is to always include /per unit of time for fluxes such as precipitation or E.

Figures 3-5: I find these figures very unappealing as for some conditions it is impossible to read properly.

A very appealing aspect of previous scenario neutral approaches to climate change impact is presenting the relative changes in the flux of interest (here PET) as a function of the relevant drivers (here temperature, relative humidity, solar radiation and wind speed) (e.g. See Prudhomme et al., 2010; fig 6). I think your paper can benefit from a similar type of plots. I understand that making such a plot is difficult since you have more relevant drivers, but you could to it for e.g. the most important 2 or 3 drivers. Such plots help the reader to conceptualize your findings better.

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ED: Publish subject to revisions (further review by Editor and Referees) (01 Mar 2017) by Nunzio Romano

AR by Danlu Guo on behalf of the Authors (19 Mar 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (20 Mar 2017) by Nunzio Romano

RR by Anonymous Referee #4 (20 Mar 2017)

ED: Publish as is (20 Mar 2017) by Nunzio Romano

AR by Danlu Guo on behalf of the Authors (27 Mar 2017)

Short summary

This study assessed the impact of baseline climate conditions on the sensitivity of potential evapotranspiration (PET) to a large range of plausible changes in temperature, relative humidity, solar radiation and wind speed at 30 Australian locations. Around 2-fold greater PET changes were observed at cool and humid locations compared to others, indicating potential for elevated water loss in the future. These impacts can be useful to inform the selection of PET models under a changing climate.