Comments to the article by Zarylbek Rakhmatilla uulu, Ryskul Usubaliyev, Andrey V. Mitusov “Broadband albedo and area changes of the Ak-Shyjrak Glacier Massif during 1994-2018, Tien Shan, Kyrgyzstan”

A.G. Terekhov

https://doi.org/10.29258/CAJWR/2020-R1.v6-1/82-82.eng

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One of the study’s objectives was formulated as the analysis of long-term dynamics of the broadband snow and ice albedo of the Ak-Shyjrak Mountain Massif’s glaciers.  6 (six) LANDSAT satellite images taken during 1994-2018 were used to accomplish it.

Weather characteristics are usually highly variable both between seasons as well as from year to year.  The same applies to the glacier surface albedo.  Depending on the actual weather conditions (temperatures – precipitation) prior to the satellite flight over it, a glacier may be either covered with fresh snow or not.  Likewise, albedo values may significantly vary from 0.1 (dirty ice) to 0.9 (fresh snow), i.e. the magnitude of glacier surface albedo variability due to weather is extremely high.   Thus, 6 (six) satellite images covering 24 years, each of them corresponding to a different season (from July 1 to October 6), cannot characterize the long-term glacier albedo dynamics.

The task might have been accomplished based on daily satellite monitoring, e.g. using Terra/Aqua MODIS Satellites (product MOD 09 – physical reflection coefficients).  The array of 1,800 satellite coverages [MOD 09; 2000-2019, from July to September] for this territory might have been sufficient to register the long-term change trends of the glacier surface’s spectral characteristics, but by no means the 6 LANDSAT satellites flights used in the study.

Furthermore, the work contains some serious inaccuracies.  As the relation of energy characteristics of the reflected electromagnetic flow to these of the falling one, albedo is a dimensionless parameter ranging from 0 (zero) to 1 (one).  In the article (abstract, p. 6,Table 2), albedo is indicated as a dimensional parameter (µm), i.e. allegedly measured in meters, which has no physical sense.


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How to cite:

Terekhov, A.G. (2020). Comments to the article by Zarylbek Rakhmatilla uulu, Ryskul Usubaliyev, Andrey V. Mitusov “Broadband albedo and area changes of the Ak-Shyjrak Glacier Massif during 1994-2018, Tien Shan, Kyrgyzstan”. Central Asian Journal of Water Research, 6(1), 82–82.

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