Processes governing snow ablation in alpine terrain –  detailed measurements from the Canadian Rockies

Schirmer, Michael; Pomeroy, John W.

doi:https://doi.org/10.5194/hess-24-143-2020

Articles | Volume 24, issue 1

https://doi.org/10.5194/hess-24-143-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Understanding and predicting Earth system and hydrological...

https://doi.org/10.5194/hess-24-143-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 24, issue 1

Research article

|

13 Jan 2020

Research article |

| 13 Jan 2020

Processes governing snow ablation in alpine terrain – detailed measurements from the Canadian Rockies

Michael Schirmer and John W. Pomeroy

Download

Final revised paper (published on 13 Jan 2020)
Preprint (discussion started on 14 May 2018)

Interactive discussion

Status: closed

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

- Printer-friendly version

- Supplement

RC1: 'review', Anonymous Referee #1, 05 Jun 2018
- AC1: 'Reply to reviewer 1', Michael Schirmer, 13 Dec 2018
RC2: 'Review comments for hess-2018-254', Anonymous Referee #2, 13 Jun 2018
- AC2: 'Reply to reviewer 2', Michael Schirmer, 13 Dec 2018
RC3: 'Review of hess-2018-254', Charles Luce, 20 Jun 2018
- AC3: 'Reply to Charles Luce', Michael Schirmer, 13 Dec 2018

Peer-review completion

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

ED: Reconsider after major revisions (further review by editor and referees) (07 Jan 2019) by Markus Weiler

AR by Michael Schirmer on behalf of the Authors (04 Mar 2019) Author's response

ED: Referee Nomination & Report Request started (16 Mar 2019) by Markus Weiler

RR by Anonymous Referee #2 (03 Apr 2019)

Suggestions for revision or reasons for rejection

The authors have addressed all of my comments and improved the readability of the manuscript. I have just a few minor comments that
they might want to consider before resubmission. All comments refer to the most recent version (without track changes).
P1L16: I would suggest to introduce “HS” as abbreviation for “snow depth” here and to use it throughout the abstract.

P1L28: “Analysing the reasons for a missing correlation in this study area provided some prerequisites for large spatial correlations and for when these need to be taken into account by SCD curves.” What do you mean by “some prerequisites for large spatial correlations”?

P2L1-2: “models […] must account for correlations between SWE and melt […]”, this seems to contradict your earlier statement that there is “… only a weak spatial correlation developed between initial snow depth and dHS”.

P2L32: Missing “that” in “There are studies have found…”

P2L10: Remove “by” in “LiDAR by…”

P3L18-22: “On the other side, spatially varying melt rates […] can alter this pre-melt SWE distribution and, when correlated to SWE, result in a spatial variability to SCD […]” This statement is confusing. Do you mean that pre-melt SWE is correlated to SWE which is measured during melt? What is spatially variable to SCD? Is this a grammar error?

P7L2-3: “As such HS and dHS are analysed and interpreted as proxies for SWE and melt in the text.” I would have thought that dHS is a proxy for ablation (mainly melt and redistribution) rather than melt alone.

P13L1-2: “The lack of correlation in the Fig. 5c point cloud was contributed to by compensation between the positive correlation driven by melt energy and the negative correlation from a cold content.” I do not understand from the previous discussion of Figure 5c (P12L17-31) how you can reach this conclusion. Melt energy and cold content were not explicitly analyzed, so your statement seems to be rather hypothetical. Although you discuss melt energy and cold content much later on P17, it might be useful to add a reference to this discussion to the earlier statement on P12.

P13L14-15: “Remote sensing techniques such as remote sensing can determine where deep drifts occur on north-facing slopes […]”

P14L6-14: How was this correlation analysis done? Did you compare spatial or temporal patterns of ablation (dHS)?

P17L11-12: “The large scatter between HS0 and dHS results from the observation that most of the variance of HS0 occurs at much smaller scales (Fig. 7a).” Doesn’t this statement refer to Figure 8c? Figure 7a refers to dHS, not HS0.

Figures 2-6: Sub-plot references (a, b, c and d) are missing in all figures.

Figure 5: What are the red, blue and yellow data points in Figure 5c? Please indicate in the caption that you show data of P1 only.

Figure 8: The caption seems incomplete, e.g., what are “dHS.irradiance” and “dHS.HS0”?

Hide

RR by Charles Luce (04 Jul 2019)

Suggestions for revision or reasons for rejection

The authors have done a nice job revising the paper. The introduction is much more succinct and focused on the problem needing to be solved, and the novel contribution is outlined and given in the conclusions.

There is a little bit of new writing that left some concern for me. P4 lines 20-25 presents what seems to be not entirely a fair, nor necessarily accurate, criticism of using empirical modeling of initial SWE variability. While the Dornes citation is given for inconsistency between years (but also discusses correlations with melt, which steps outside of the initial SWE variability issue), others, Luce and Tarboton (2004) as one example, show the opposite, relatively consistent SCD curves across years (at least when presented dimensionlessly, which is not how everyone describes SCD curves). The Dornes work certainly gives pause with respect to generality, but this paragraph gives the impression of concluding that one should not use initial SWE variability based on empirical information period. At the same time, the current manuscript eventually concludes that initial SWE variability is the most important factor in the current study, but does not actually assess interannual variability in the initial distribution. The concluding sentence states that it is not possible to evaluate the impacts of correlations without first knowing the contribution from initial variability. Again, the critiqued methods do just that (at least one of them does). It seems strange to criticize these methods for this issue in this manuscript, when this manuscript mostly notes that scale mismatches may be a key reason for not finding spatial correlations between melt and initial SWE distributions. If this paragraph fits into this paper, a more balanced discussion is necessary. It seems reasonable to see the issue presented as a question, or even a point of difference among sites that could be measured with replication, but the current way it is presented makes the issue look settled.

Hide

ED: Publish subject to minor revisions (review by editor) (15 Aug 2019) by Markus Weiler

AR by Michael Schirmer on behalf of the Authors (20 Sep 2019) Author's response Manuscript

ED: Publish as is (17 Oct 2019) by Markus Weiler

AR by Michael Schirmer on behalf of the Authors (04 Nov 2019)

Short summary

The spatial distribution of snow water equivalent (SWE) and melt are important for hydrological applications in alpine terrain. We measured the spatial distribution of melt using a drone in very high resolution and could relate melt to topographic characteristics. Interestingly, melt and SWE were not related spatially, which influences the speed of areal melt out. We could explain this by melt varying over larger distances than SWE.