Growth of the fast ice and its influence on the freezing of bottom sediments in the Buor-Khaya Bay coastal zone, Laptev Sea (in Russian)

Results of the ice and hydrological measurements carried out in the winter of 2014/15 in theTiksiGulf(Buor-KhayaBay) are described. These data served a basis for development of a conceptual thermodynamic model of seasonal freezing of the sea water layers and underlying bottom sediments in the sea-shore zone. The model uses two methods of localization of the phase transition zones: a classical (frontal) one is used for water, while another one within the range of temperatures – for the bottom. For real atmospheric conditions, we investigated specific features of the water freezing through in the shallow coastal zone of theLaptev Sea. The quantitative characteristics of the process were obtained. The calculations demonstrated that the distinguishing feature of the process is a stabilization of the ice thickness, taking place due to essential increasing of a salinity of the sea water. As a result of this, a shallow water body does not frozen through down to the bottom at even the very low air temperatures. Cooled salt waters does not allow liquid to be frozen in pores of the bottom ground. Salinization of the under-ice water layer can cause the melting of fast ice in the shallow water with its simultaneous increase away from the coast. Ice formation in water layers and bottom sediments begins at the same time, although it proceeds differently at different depths. Due to salinization of the bottom ground a continuous frozen zone is not formed, and the whole layer of freezing precipitation is a two-phase (partially frozen) area. As a whole, the model estimates of the process parameters including the motions of the phase fronts agree with known data of direct measurements. Despite such conformity, the model data should be considered as only evaluative ones. If a bottom is flat, the horizontal mixing and advection, which are not reproduced by a one-dimensional model in principle, the actual salinity parameters will most likely not reach the calculated values. However, for small values of the tides in theBuor-KhayaBayand insignificant reverse flows of salt, effect of the last ones does not apparently exert significant influence on the intensity of cooling of the under-ice water layer as well as on the ice formation in upper layers of the bottom within such time scales as a season

Динамика сезонного протаивания мерзлоты в районе научно-исследовательского стационара «Ледовая база “Мыс Баранова”» (о. Большевик, арх. Северная Земля)

The results of permafrost observations in the northern part of theBolshevikIsland(Severnaya Zemlya Archipelago) started in February 2016 at the meteorological site of the research station “Ice Base “CapeBaranov” are presented. Features of two-year measurements of temperature, heat flux and humidity in the soil active layer due to the processes of its seasonal thawing/freezing, including the so-called “zero curtain effect” are described. The review of climatic and landscape characteristics of the research area, as well as the parameterization of thermophysical properties of the three main types of arctic soils (sandy, sandy loamy and clayey) in the frozen and thawed state was performed. Using the stationary model, realizing the Kudryavtsev’s algorithm, the data of atmospheric reanalysis and direct meteorological observations, interannual variability of seasonal thawing depth as well as mean annual temperature of permafrost surface for various soil types on theBolshevikIslandwere obtained. It is shown that the permafrost-climatic changes during last 70 years, despite significant interannual fluctuations, reflecting the variability of atmospheric conditions at the Severnaya Zemlya Archipelago, are consistent with global temperature increase, and taken into account variations in the snow layer thicknesses and vegetation cover are close to the same measured in 2016–2017 years.Представлены результаты первых мерзлотных наблюдений в северной части о. Большевик (арх. Северная Земля), начатых в феврале2016 г. на НИС «Ледовая база “Мыс Баранова”». Описаны особенности температурной структуры и влажности деятельного слоя грунта, обусловленные процессами сезонного протаивания/промерзания, включая так называемый «эффект нулевого занавеса». Выполнена параметризация теплофизических свойств основных типов арктических грунтов в мерзлом и талом состоянии. С помощью стационарной модели, основанной на известном алгоритме Кудрявцева, данных атмосферного реанализа и прямых метеонаблюдений получены оценки многолетней изменчивости глубины сезонного протаивания грунтов о. Большевик. Показано, что мерзлотно-климатические изменения последних 70 лет, несмотря на существенные межгодовые колебания, согласуются с ходом глобального повышения температуры

A model of melt pond evolution on sea ice

A one-dimensional, thermodynamic, and radiative model of a melt pond on sea ice is presented that explicitly treats the melt pond as an extra phase. A two-stream radiation model, which allows albedo to be determined from bulk optical properties, and a parameterization of the summertime evolution of optical properties, is used. Heat transport within the sea ice is described using an equation describing heat transport in a mushy layer of a binary alloy (salt water). The model is tested by comparison of numerical simulations with SHEBA data and previous modeling. The presence of melt ponds on the sea ice surface is demonstrated to have a significant effect on the heat and mass balance. Sensitivity tests indicate that the maximum melt pond depth is highly sensitive to optical parameters and drainage. INDEX TERMS: 4207 Oceanography: General: Arctic and Antarctic oceanography; 4255 Oceanography: General: Numerical modeling; 4299 Oceanography: General: General or miscellaneous; KEYWORDS: sea ice, melt pond, albedo, Arctic Ocean, radiation model, thermodynami

РОСТ ПРИПАЯ И ЕГО ВЛИЯНИЕ НА ЗАМЕРЗАНИЕ ВЕРХНЕГО СЛОЯ ДОННЫХ ОТЛОЖЕНИЙ В ПРИБРЕЖНОЙ ЗОНЕ ГУБЫ БУОР-ХАЯ (МОРЕ ЛАПТЕВЫХ)

Results of the ice and hydrological measurements carried out in the winter of 2014/15 in theTiksiGulf(Buor-KhayaBay) are described. These data served a basis for development of a conceptual thermodynamic model of seasonal freezing of the sea water layers and underlying bottom sediments in the sea-shore zone. The model uses two methods of localization of the phase transition zones: a classical (frontal) one is used for water, while another one within the range of temperatures – for the bottom. For real atmospheric conditions, we investigated specific features of the water freezing through in the shallow coastal zone of theLaptev Sea. The quantitative characteristics of the process were obtained. The calculations demonstrated that the distinguishing feature of the process is a stabilization of the ice thickness, taking place due to essential increasing of a salinity of the sea water. As a result of this, a shallow water body does not frozen through down to the bottom at even the very low air temperatures. Cooled salt waters does not allow liquid to be frozen in pores of the bottom ground. Salinization of the under-ice water layer can cause the melting of fast ice in the shallow water with its simultaneous increase away from the coast. Ice formation in water layers and bottom sediments begins at the same time, although it proceeds differently at different depths. Due to salinization of the bottom ground a continuous frozen zone is not formed, and the whole layer of freezing precipitation is a two-phase (partially frozen) area. As a whole, the model estimates of the process parameters including the motions of the phase fronts agree with known data of direct measurements. Despite such conformity, the model data should be considered as only evaluative ones. If a bottom is flat, the horizontal mixing and advection, which are not reproduced by a one-dimensional model in principle, the actual salinity parameters will most likely not reach the calculated values. However, for small values of the tides in theBuor-KhayaBayand insignificant reverse flows of salt, effect of the last ones does not apparently exert significant influence on the intensity of cooling of the under-ice water layer as well as on the ice formation in upper layers of the bottom within such time scales as a season.Представлены и проанализированы данные стандартных ледовых наблюдений зимой 2014/15 г. в бухте Тикси (губа Буор-Хая, южная часть моря Лаптевых). Описаны особенности изменчивости поля температур в припайном льду и подлёдном слое моря. Данные наблюдений дополнены модельными оценками замерзания слоя воды и верхних слоёв донных отложений

Phenomenology of the Lense-Thirring effect in the Solar System

Recent years have seen increasing efforts to directly measure some aspects of the general relativistic gravitomagnetic interaction in several astronomical scenarios in the solar system. After briefly overviewing the concept of gravitomagnetism from a theoretical point of view, we review the performed or proposed attempts to detect the Lense-Thirring effect affecting the orbital motions of natural and artificial bodies in the gravitational fields of the Sun, Earth, Mars and Jupiter. In particular, we will focus on the evaluation of the impact of several sources of systematic uncertainties of dynamical origin to realistically elucidate the present and future perspectives in directly measuring such an elusive relativistic effect.Comment: LaTex, 51 pages, 14 figures, 22 tables. Invited review, to appear in Astrophysics and Space Science (ApSS). Some uncited references in the text now correctly quoted. One reference added. A footnote adde

Thermomechanical erosion modelling of Baydaratskaya Bay, Russia with COSMOS

Rapid coastal erosion threatens Arctic coastal infrastructure, including communities and industrial installations. Erosion of permafrost depends on numerous processes, including thermal and mechanical behaviour of frozen and unfrozen soil, nearshore hydrodynamics, atmospheric forcing, and the presence of sea ice. The quantification and numerical modelling of these processes is essential to predicting Arctic coastal erosion. This paper presents a case study of Baydaratskaya Bay, Russia, using the COSMOS numerical model to predict thermal-mechanical erosion. In particular, this study focuses on thermoabrasional rather than thermodenudational processes. A field dataset of onshore thermal and mechanical soil characteristics was supplemented by sources from the literature to serve as input for the model. A detailed sensitivity analysis has been conducted to determine the influence of key parameters on coastal erosion rates at the study site. This case study highlights the need for expanded data collection on Arctic coastlines and provides direction for future investigations

Sea ice growth at nonstationary ocean-atmosphere heat exchange

A thermodynamic model of sea snow-ice cover growth under the influence of heat flows on its upper and lower surfaces is presented. The growing is described with an extended region of phase transition (a two-phase region) with a linear temperature distribution. The temperature of the upper surface is calculated with the use of a heat-balance equation on the basis of determinable meteorological observation data. The comparison of the model results with freezing experimental data is performed