Ground-Based Oblique-View Photogrammetry and Sentinel-1 Spaceborne RADAR Reflectivity Snow Melt Processes Assessment on an Arctic Glacier

Round 1

Reviewer 1 Report

1)    Line 23-24: “in each case, it was …… to increased run-offs and melt water fluxes”. Up to now, there is no general conclusion on “the increase of precipitation leads on to more snow accumulation”. When the temperature increase, in some region, the increase precipitation may lead to the increase of rainfall not snowfall. And change “to increased” to “to increase”

2)    Line 37: “the fraction of snow cover (FSC)” ----> “fractional snow cover (FSC)”

3)    Section 1: Please add some literatures review about the combination of radar and optical sensor images to monitor surface snow/ice.

4)    Lines 152-155: Add the reference related to the threshold selection or show me the selection experiment. I can not follow your description how do you determine snow/ice cover with RADAR data. Please show me more detail information on the generation procedure of snow cover map.

5)    In “Results and analysis” section, authors show the readers that the presentation of the results is limited to a qualitative presentation only and lacks the results of a quantitative analysis. It is important to show not only the differences in snow accumulation provided by different sensors, but also to tell the reader quantitatively how much information each sensor can complement.

6)    It is widely known that microwave sensor can compensate more information that the optical sensor cannot provide. This study only qualitatively shows the readers this facts. I think a large number of quantitative analysis experiments should be added.

Author Response

Please see attached PDF

Author Response File: Author Response.pdf

Reviewer 2 Report

Nice paper adressing major issues of snow hydrology. It's an innovative approach to combine year round field camera observations from high elevated positions with oprical and microwave remote senisng data.

Nevertheless, there is one point too less addressed. These are the slush flow hazards, when a massive, completely wet and saturated snow pack is flushing down from the glacier surface. Especially in these high latitudes in Spitsbergen, when in summer there is no sunset, the amount of energy acquired by the snow pack is tremendous. This seems to be so far an underestimated hazard around the arctic. My suggestion would be to observe the duration of sunny weather periods, since this might be an indicator of the slush flow danger. There is a nice publication on this:

Scherer, D. (1994):
Slush Stream Initiation in a High Arctic Drainage Basin in NW-Spitsbergen - An Energy Balance Based Approach Combining Field Methods, Remote Sensing and Numerical Modelling. stratus 1, Basel, Diss., Abt. für Meteorologie & Klimaökologie, Georgraph. Inst. der Univ. Basel, 94 S. ISBN 3859772406.

There is a contradiction to the explanations in the whole text with Figure 7, where it is clearly visible, that moist snow has a higher backscatter (blue) than dryer snow (red), as also displayed on the left side of the Figure 7 with the optical NDWI.

"spaceborne" with "e" at the end

line 137: "an" instead of "and"

Author Response

Please see attached document

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

It has address most of my concerns.  But author still do not provide the statistics analysis on his results.   Whether this paper is published or not depends on the editor.