Spatial Estimation of Snow Water Equivalent for Glaciers and Seasonal Snow in Iceland Using Remote Sensing Snow Cover and Albedo

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

General Comments

 

This paper uses established methods for reconstruction of SWE using SCA and albedo data (various citations given). While this in itself is not novel, the application to Iceland is novel. There is not much widely circulated literature on seasonal snow in Iceland. The differentiation between seasonal snow and glaciers is very interesting. Unfortunately, many of the unique citations (e.g., 9-22) have no DOIs and are in Icelandic. It would be great if some of those were accessible. Perhaps the authors can at least provide an English translation of the titles of these documents. Further, these (and other) citations seem rather incomplete.

 

None of the data are available, except through citations, which, as stated previously, are not complete or in English. I know that this is likely a policy issue, but it makes it difficult to evaluate any of the work undertaken here.

 

In the bigger picture, the paper is fine. The writing is choppy and the authors should consider how they put the pieces together. I recommend that they write research objectives at the end of the Introduction and use those to guide their writing.

 

 

Specific Comments:

-        Introduction: overall it is acceptable, but the various single sentence paragraphs are not acceptable. It provides useful information, but reads rather choppy.

-        Lines 56-60: where the “Long-term observations of snow cover (binary snow cover)” just no present or not? This is unclear.

-        Some statements in the Introduction (and elsewhere) need citations, such as “In an average hydrological year, about 60 % of flows for hydropower energy production originate from seasonal snow (10 to 15 %) and glacier ablation (50 %).” Where does this come from? Does this mean that glaciers are at a significant negative mass balance?

-        Lines 114-118: can specific research objectives be stated after the purpose?

-        Lines 138 and 331: this is not validation, but rather evaluation.

-        Lines 156-157: is this the height of the sensor? Unclear: “radiation sensors which have relatively uniform spectral response ranging from 0.3 to 2.8 m”

-        Sections 3.1 and 3.4: a station map would be useful. For 3.4, the reader has no idea where Setur is

-        Line 211 and beyond (e.g., Figure 4): what is the maximum SWE that can be measured by the CS725?

-        Section 5 is Results and Discussion

-        Figure 5 is confusing. Consider separating into two figures of seasonal snow and glacier melt.

-        Figure 6: it would be useful for the reader’s visual comparison to have the same scale for each month. It could be a non-linear color-ramp to consider the difference between April and July

-        Figure 11: why are there lines as series of dots in this figure? What is this an artifact of?

-        The Conclusions are mostly a summary. That may be what MDPI wants, but as a reader, I want to know the key results and their implications.

-        The Appendices need more information to tell the reader what is in them, more than just the Figures/Tables.

-        Check the citations. Some of are incomplete, such as not including the journal name

Comments on the Quality of English Language

The Quality of English Language is fine. The issue with this paper is the structure is not easy to follow, with numerous single sentence paragraphs. Statements in the Results section starting with "Figure X shows ..." are discouraged. The reader should know what the figure is if the caption is appropriate. 

Author Response

Please see the attached document

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript estimates regional SWE using spatially distributed energy balance model and satellite-based retrievals of albedo and snow cover product, it will certainly contribute to the cryosphere, especially the snow hydrology research area. I think the content of the original manuscript is sufficient and the methodology is innovative. However, I still have some comments which should be noticed by the authors.

 

(1)    The snow water equivalent can also be inverted using remote sensing, and there are currently several remote sensing data products. How do these products compare with the method in this article? Or can passive microwave remote sensing data be added to the method in this article to assist in determining the snow water equivalent and melting situation?

(2)    How to convert to SWE from available melt energy? Please clarify that, it is not clearly stated in the moment manuscript.

(3)    The article is estimating the snow water equivalent on the ground or the snow water equivalent generated by melting, and these two aspects are not distinguished in many places of the manuscript, which is very confusing.

(4)    From Fig.4, it shows that the SWE estimation errors are a little bit large, will the final conclusion be affected by using such a large error data?

(5)    P. 21, Line 584, “Statistically significant trends (p >0.05) are shown with stipples”, significant trends should be represented by p <0.05, isn’t it ?

Author Response

Please see the attached document

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors, 

 

I was invited to review your manuscript: “Spatial estimation of snow water equivalent for glaciers and seasonal snow in Iceland using remote sensing snow cover and albedo”. 

 

In my opinion, the manuscript is acceptable in its present form. However, the minimal correction is still possible to apply to improve the text, tables and figures (small list of corrections I would suggest to apply). 

 

Line 101: What do you mean by “snow-age-based empirical relations”? 

Line 107: I would suggest adding the explanation for the abbreviation SNOTEL (first time in text).

Line 117-118. The abbreviation MODIS is already given in the line 103, it does not need to repeat it.

Table 1: please, check the width of the third column.

Table 2: please, correct the width of the table and second column.

Line 165. The first sentence repeats the previous text. 

Line 252: “... long-wave …” radiation?

Fig. 3 : there is no color bar given.

Table A1: please, fit the width of column four. 

Fig A1: what is SWE GL? Please explain in the notation to the figure.

 

with the best regards,

Anonymous referee 

 

Author Response

Please see the attached document

Author Response File: Author Response.pdf