Effect of thaws on snow cover and soil freezing under the contemporary climate change

IF 0.7 Q4 GEOSCIENCES, MULTIDISCIPLINARY

Led i Sneg-Ice and Snow Pub Date : 2019-12-01 DOI:10.15356/2076-6734-2019-4-433

A. V. Sosnovsky, N. Osokin

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引用次数: 4

Abstract

Thaw and liquid precipitation retard cooling of snow cover and soil surface and so may be a factor of heating. This slows down the soil freezing due to more active freezing of the wet snow, and, thus, promotes cooling and re-cooling of the soil. However, there are a number of factors which intensify the soil freezing after thaw. With thaw, the thickness of the snow cover decreases, and its density increases. In addition, after freezing wet snow improves the contact between the ice crystals, which increases the hardness and thermal conductivity of the snow. As a result, after the thaw, the thermal protection ability of the snow decreases, and this can accelerate freezing of the soil. The dynamics of snow accumulation in Russia is considered in the paper. Using data obtained in the Western Svalbard, we demonstrate the increase in the number of thaws and liquid precipitation and influence of them on the snow cover and soil freezing. The influence of thaw on the growth of thermal resistance of snow cover is also considered. Calculations have shown that in the absence of a thaw, the depth of soil freezing is 1.26 m. With a thaw lasting 10 days, which begins on the 40th day from the start of soil freezing, the depth of freezing is reduced down to 1.2 m without considering changes in snow cover. When taking into account changes in the thermal resistance of snow cover, the depth of soil freezing by the end of the cold period increases up to 1.32 cm. With a thaw in the mid-winter, i.e. on the 70th day, the depth of freezing decreases down to 1.22 m, that is smaller than the depth of freezing without thaw. This scenario is in accordance with changes in snow accumulation dynamics under the present-day climate, as in many areas most of the solid precipitation falls in the first half of the cold period. As a result, for a period after a thaw the smaller volume of snow will be deposited, and this will retard increasing in thermal resistance of the snow cover.

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当代气候变化下融雪对积雪和土壤冻结的影响

解冻和液体降水延缓了积雪和土壤表面的冷却，因此可能是加热的一个因素。由于湿雪的更活跃的冻结，这减缓了土壤的冻结，因此，促进了土壤的冷却和再冷却。然而，有许多因素加剧了解冻后土壤的冻结。随着解冻，积雪厚度减小，密度增大。此外，冻湿后的雪改善了冰晶之间的接触，从而增加了雪的硬度和导热性。因此，在解冻后，雪的热防护能力下降，这可以加速土壤的冻结。本文考虑了俄罗斯积雪的动力学过程。利用在斯瓦尔巴群岛西部获得的数据，我们证明了融化和液体降水数量的增加以及它们对积雪和土壤冻结的影响。还考虑了解冻对积雪热阻增长的影响。计算表明，在没有解冻的情况下，土壤冻结深度为1.26米。解冻持续10天，从土壤冻结开始的第40天开始，在不考虑积雪变化的情况下，冻结深度降低到1.2 m。考虑到积雪热阻的变化，寒期结束时土壤冻结深度增加到1.32 cm。隆冬解冻后，即第70天，冻结深度减小至1.22 m，小于未解冻时的冻结深度。这一情景与当今气候下的积雪动态变化相一致，因为在许多地区，大部分固体降水发生在寒冷期的前半段。因此，在解冻后的一段时间内，较小体积的雪将被沉积，这将减缓积雪热阻的增加。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Led i Sneg-Ice and Snow GEOSCIENCES, MULTIDISCIPLINARY-

CiteScore

1.50

自引率

42.90%

发文量

审稿时长

8 weeks

期刊介绍： The journal was established with the aim of publishing new research results of the Earth cryosphere. Results of works in physics, mechanics, geophysics, and geochemistry of snow and ice are published here together with geographical aspects of the snow-ice phenomena occurrence in their interaction with other components of the environment. The challenge was to discuss the latest results of investigations carried out on Russia’s territory and works performed by Russian investigators together with foreign colleagues. Editorial board works in collaboration with Glaciological Association that is professional community of specialists in glaciology from all republics of the Former Soviet Union which are now new independent states. The journal serves as a platform for the presentation and discussion of new discoveries and results which help to elucidate the state of the Earth’s cryosphere and the characteristics of the evolution of the snow-ice processes and phenomena under the current conditions of rapid climate change.