Influence of snow cover on the thermal regime of a polythermal glacier in Western Spitsbergen

Сосновский, В.; Мачерет, Я.; Глазовский, Ф.; Лаврентьев, И. И.

doi:10.15356/2076-6734-2015-3-27-37

Cited by 3 publications

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References 7 publications

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“…Снежный покров существенно влияет на локальный и региональный климат, термиче ский режим подстилающих пород [1][2][3], баланс массы ледников, а также ледниковый и речной сток [4,5] . Основные его параметры -толщи на, структура и плотность -определяют снего запасы и теплоизолирующие свойства снежного покрова .…”

Section: Introductionunclassified

Snow Thickness on Austre Grønfjordbreen, Svalbard, From Radar Measurements and Standard Snow Surveys

et al. 2018

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Comparison of two methods of measurements of snow cover thickness on the glacier Austre Grønfjordbreen, Svalbard was performed in the spring of 2014. These methods were the radar (500 MHz) observations and standard snow surveys. Measurements were conducted in 77 different points on the surface of the glacier. A good correlation (R 2 = 0.98) was revealed. In comparison with the data of snow surveys, the radar measurements show a similar but more detailed pattern of the distribution of the snow cover depth. The discrepancy between the depths of snow cover on maps plotted from data of both methods did not exceed 30 cm in most parts of the glacier. The standard error of interpolation of the radar data onto the entire glacier surface amounts, on average, to 18 cm. This corresponds to the error of radar measurements of 18.8% when an average snow depth is about 160 cm and 9.4% at its maximum thickness of 320 cm. The distance between the measurement points at which the spatial covariance of the snow depth disappears falls between 236 and 283 m along the glacier, and between 117 and 165 m across its position. We compared the results of radar measurements of the pulse-delay time of reflections from the base of the snow cover with the data of manual probe measurements at 10 points and direct measurements of snow depth and average density in 12 snow pits. The average speed of radio waves propagation in the snow was determined as V cr = 23.4±0.2 cm ns −1 . This magnitude and the Looyenga and Kovacs formulas allowed estimating the average density of snow cover ρ L = 353.1±13.1 kg m −3 and ρ K = 337.4±12.9 kg m −3 . The difference from average density measured in 12 pits ρ av.meas = 387.4±12.9 kg m −3 amounts to −10.8% and −14.8%. In 2014, according to snow and radar measurements, altitudinal gradient of snow accumulation on the glacier Austre Grønfjordbreen was equal to 0.21 m/100 m, which is smaller than the average values (0.35 m/100 m). According to the results of snow measurements of 2011-2014, the average thickness of the snow cover on the glacier Austre Grønfjordbreen was by 17 cm greater than in 1979. In the very snowy year 2012, it was higher by 21.5 cm in comparison with the year 1979, and its spatial variability (standard deviation σН) had increased by 25.6 cm. Estimates of spatial and temporal variability of snow cover depth will be used to analyze the hydrothermal state of the glacier and its changes with regard to revealed features and climatic trends.

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Section: Introductionunclassified

Snow Thickness on Austre Grønfjordbreen, Svalbard, From Radar Measurements and Standard Snow Surveys

et al. 2018

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Hydrothermal structure of a polythermal glacier in Spitsbergen by measurements and numerical modeling

et al. 2016

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Thickness of the upper cold ice layer in the ablation area of the polythermal glacier Grønfjordbreen (Spitsbergen) was estimated by means of numerical modeling. The results were compared with data of radio-echo sounding of the same glacier obtained in 1979 and 2012. Numerical experiments with changing water content in the lower layer of temperate ice and surface snow cover thickness made possible to compare calculated and modeled cold ice thicknesses and to estimate their changes for 33‑year period caused by regional climate change. According to data of radio-echo sounding, thickness of the cold ice layer decreased, on average, by 34 m. Numerical modeling shown similar results: the cold ice layer became thinner by 31 m and 39 m at altitudes 100–300 a.s.l. under the snow cover thickness of 1 m and 2 m. We explain this by rising of annual mean air temperature by 0,6 °С as compared to data of the nearest meteorological station Barentsburg in the same period. We believe that changes in cold ice layer thickness in polythermal glaciers can be used for estimation of changes in such regional climatic parameter as mean air temperature at different altitudes of the glacier surface in the ablation area.

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Mass Balance of Austre Grønfjordbreen, Svalbard, 2006–2020, Estimated by Glaciological, Geodetic and Modeling Aproaches

et al. 2021

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Glacier mass balance measurements, reconstructions and modeling are the precondition for assessing glacier sensitivity to regional climatic fluctuations. This paper presents new glaciological and geodetic mass balance data of Austre Grønfjordbreen located in the western part of Nordenskiöld Land in Central Spitsbergen. The average annual mass balance from 2014 to 2019 was −1.59 m w.e. The geodetic mass balance from 2008 to 2017 was −1.34 m w.e. The mass balance was also reconstructed by the temperature-index model from 2006 to 2020 and by spatially-distributed energy-balance models for 2011–2015 and 2019. We found a cumulative mass balance of −21.62 m w.e. over 2006–2020. The calculated mass-balance sensitivity to temperature was −1.04 m w.e. °C−1, which corresponds to the highest glacier mass balance sensitivity among Svalbard glaciers. Sensitivity to precipitation change was 0.10 m w.e. for a 10% increase in precipitation throughout the balance year. Comparing the results of the current study with other glacier mass balance assessments in Svalbard, we found that Austre Grønfjordbreen loses mass most rapidly due to its location, which is mostly influenced by the warm West Spitsbergen Current, small area and low elevation range.

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Influence of snow cover on the thermal regime of a polythermal glacier in Western Spitsbergen

Cited by 3 publications

References 7 publications

Snow Thickness on Austre Grønfjordbreen, Svalbard, From Radar Measurements and Standard Snow Surveys

Snow Thickness on Austre Grønfjordbreen, Svalbard, From Radar Measurements and Standard Snow Surveys

Hydrothermal structure of a polythermal glacier in Spitsbergen by measurements and numerical modeling

Mass Balance of Austre Grønfjordbreen, Svalbard, 2006–2020, Estimated by Glaciological, Geodetic and Modeling Aproaches

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