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

• Published in: Ice and Snow
• Main Authors: A. Sosnovsky V., N. Osokin I., А. Сосновский В., Н. Осокин И.
• Other Authors: The mathematical modeling was carried out according to the framework of fundamental scientific studies within the project reg. № 0148-2019-0004, processing and analysis of experimental data were carried out according to the Russian Foundation for Basic Research (RFBR) 1755-80107 BRICS_a project, numerical experiments and their analysis was supported by the RFBR, grant No 18-05-60067, field studies on Svalbard were conducted with financial support from the state assignment and logistical assistance of the Russian Scientific Center on Spitsbergen (RSCS)., Математическое моделирование проводилось в рамках темы Государственного задания № 0148-2019-0004, обработка и анализ архивных материалов – по проекту РФФИ 17-5580107 БРИКС_а, численные эксперименты и их анализ – при поддержке гранта РФФИ № 18-0560067, экспедиционные исследования на архипелаге Шпицберген – при финансовой поддержке госзадания и логистической помощи Российского научного центра на Шпицбергене (РНЦШ).
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: IGRAS 2019
• Subjects: climate changes; depth of soil freezing; liquid precipitation; mathematical modeling; snow cover; thaws; thermal conductivity; глубина промерзания грунта; жидкие осадки; климатические изменения; математическое моделирование; оттепели; снежный покров; теплопроводность; Svalbard; Arctic; The Cryosphere
• Online Access: https://ice-snow.igras.ru/jour/article/view/625; https://doi.org/10.15356/2076-6734-2019-4-433

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 Рассмотрено влияние климатических изменений на динамику ...