Snow-ice Cover Research Articles

Особенности эксплуатации лесовозных дорог в весенне-зимний период

Seasonal roads are not capital construction objects. Unlike all-season ones, they can be of summer and winter action. During the transport development of forests, both allseason paved roads and temporary unpaved roads are required. The share of temporary roads is more than 90 % of all logging roads. One of the main problems of temporary logging roads is uneven seasonal operation, especially in summer. Seasonal roads do not have a permanent surface; more often it is natural soil, subject, except for mechanical impacts, to atmospheric ones, which is most evident in the summer-autumn period. Therefore, about 80 % of the harvested wood is exported via winter roads. The density of temporary roads depends on the general harvesting technology in a particular area, including the wood skidding distance and the angle of relative position of forest roads. Winter road construction works are carried out in summer and winter. In summer, engineering surveys are carried out, the optimal direction of the future route is determined, a clearing is cut, a roadbed is prepared, and if necessary, culverts are installed. With the onset of cold weather, the existing soil is compacted and leveled to accelerate its freezing. If the roadbed is sufficiently frozen, a snow-ice cover is formed. The article considers the influence of roadside forest plantations on the air temperature near the road surface, soil temperature, blocking solar radiation – the factors that are directly related to the overall service life of a winter road. Special attention is paid to slowing down the decrease in the winter road pavement strength in the shade of preserved trees by choosing the optimal route direction. The slowdown in the decrease in the pavement strength of the forest dirt road has been established and confirmed in areas where solar radiation is blocked by trees, i.e. in the shade. The difference in strength reduction to the minimum is 33 days. Based on the research results, it has been concluded that a comprehensive development of the logistics strategy for the organization of roundwood transportation via winter roads is necessary.

ПАРАМЕТРИЗАЦИЯ ТЕПЛО- И ВЛАГООБМЕНА В РЕГИОНАЛЬНОЙ ТЕРМОДИНАМИЧЕСКОЙ МОДЕЛИ МОРСКОГО ЛЬДА

The prevailing types of the atmospheric stratification over the snow-ice cover at the top of Taganrog Bay for eleven winter seasons of 2007/2008-2017/2018 have been determined using the numerical experiments on reproducing the seasonal variations in the sea ice thickness. Series of calculations both with the constant transfer coefficients and with the coefficients obtained taking into account the surface stratification of the atmosphere have been carried out. The model results of both series have been compared with each other and with in situ measurements.

Application of the CHIMERE-WRF Model Complex to Study the Radiative Effects of Siberian Smoke Aerosol in the Eastern Arctic

We describe a computational technology for studying the effects of the aerosol-radiation interaction and calculating regional estimates of the direct (DRE) and semidirect radiative effects (SDRE) of biomass burning (BB) aerosol based on simulations with the CHIMERE chemistry transport model coupled with the WRF meteorological model. The technology was applied to numerical studying the radiative effects of Siberian biomass burning aerosol in the eastern Arctic in the period of July 16–31, 2016. The model simulations show that Siberian smokes, on the whole, had a significant cooling effect on the atmosphere in the eastern Arctic in that period due to the DRE, the value of which at top of the atmosphere was, on average, −6.0 W m−2, being minimal over the snow-ice cover of the ocean (−1.2 W m−2). At the same time, the contribution of the Siberian BB aerosol DRE to the radiative balance of the Arctic atmosphere is found to be offset to a certain extent by the SDRE, which is positive (2.0 W m−2), on average. The SDRE is formed as a result of the multihour aerosol effect on meteorological processes and plays the most important role over the snow-ice Arctic covers, where it exceeds the DRE in absolute value. It has been shown that the SDRE of Siberian BBA in our numerical experiments is mainly due to scattering (rather than absorption) of radiation by aerosol particles.

Hydroclimate and vegetation variability of high Andean ecosystems.

Mountain ecosystems are sensitive to climate fluctuations; however, the scarcity of instrumental data makes necessary the use of complementary information to study the effect of climate change on these systems. Remote sensing permits studying the dynamics of vegetation productivity and wetlands in response to climate variability at different scales. In this study we identified the main climate variables that control vegetation dynamics and water balance in Cumbres Calchaquíes, NW Argentina. For this, we built annual time series from 1986 to 2019 of Soil Adjusted Vegetation Index (SAVI, to quantify spare vegetation productivity), lake area, and snow-ice cover of peatlands, as indicators of mountain productivity and hydrology. We used a decompose function to explore trend, seasonality and random signal of the three-time series, and explored for significant changes in the mean value of consecutive periods. We used correlational analysis to explore their associations with climate records at local, regional, and global scales. The results showed that, SAVI and hydrological indicators presented different fluctuation patterns more pronounced since 2012, when they showed divergent trends with increasing SAVI and decreasing lake area and snow-ice cover. The three indicators responded differently to climate; SAVI increased in warmer years and lake area reflected the water balance of previous years. Snow-ice cover of peatlands was highly correlated with lake area. La Niña had a positive effect on lake area and snow-ice cover and a negative on SAVI, while El Niño had a negative effect on SAVI. Fluctuations of lake areas were synchronized with lake area in the nearby Argentinian puna, suggesting that climate signals have regional extent. The information provided by the three hydroclimate indicators is complementary and reflects different climate components and processes; biological processes (SAVI), physical processes (snow ice cover) and their combination (lake area). This study provides a systematic accessible replicable tool for mountain eco-hydrology long-term monitoring.

Study of climate change patterns of the Kashkadarya River basin based on GIS technologies

The article deals with the problem of studying changes in some climatic indicators (temperature, precipitation) in the Kashkadarya River basin. For this purpose, the analysis of land surface temperature and area of snow and ice cover on Landsat 8 images was used. Comparison of the obtained results with the results of analysis of archival data of Uzhydromet and water level data of gauging stations showed that the growth rate of average annual temperatures in Kashkadarya province is 0.21oC, and the rate of reduction of snow-ice cover area is 1% per year. in general, which has decreased over the past 15 years, by 75%. Such trends may lead to a significant reduction in the river flow of the Kashkadarya River in the coming years.

Dissolved Oxygen in a Shallow Ice-Covered Lake in Winter: Effect of Changes in Light, Thermal and Ice Regimes

Oxygen conditions in ice-covered lakes depend on many factors, which, in turn, are influenced by a changing climate, so detection of the oxygen trend becomes difficult. Our research was based on data of long-term measurements of dissolved oxygen (2007–2020), water temperature, under-ice solar radiation, and snow-ice thickness (1995–2020) in Lake Vendyurskoe (Northwestern Russia). Changes of air temperature and precipitation in the study region during 1994–2020 and ice phenology of Lake Vendyurskoe for the same period based on field data and FLake model calculations were analyzed. The interannual variability of ice-on and ice-off dates covered wide time intervals (5 and 3 weeks, respectively), but no significant trends were revealed. In years with early ice-on, oxygen content decreased by more than 50% by the end of winter. In years with late ice-on and intermediate ice-off, the oxygen decrease was less than 40%. A significant negative trend was revealed for snow-ice cover thickness in spring. A climatic decrease of snow-ice cover thickness contributes to the rise of under-ice irradiance and earlier onset of under-ice convection. In years with early and long convection, an increase in oxygen content by 10–15% was observed at the end of the ice-covered period, presumably due to photosynthesis of phytoplankton.

Parametrizatsiya pogloshcheniya solnechnoy radiatsii snezhno-ledyanym pokrovom v termodinamicheskoy modeli l'da Azovskogo morya

Purpose. The work is aimed at assessing the influence of choice of the parameterization scheme of the snow and ice radiation features upon reproduction of seasonal evolution of the snow-ice cover thickness and temperature distribution in it in the Taganrog Bay top part. Methods and Results. Thermal seasonal dynamics of the snow-ice cover thickness in the northeastern part of the Taganrog Bay was studied using a non-stationary thermodynamic model of sea ice. The model reproduces formation of ice and accumulation of snow on its surface, spatial-temporal change in their thermophysical characteristics, melting of the snow-ice cover, vertical distribution of temperature, and solar radiation absorbed in its thickness at a preset timed data on the meteorological parameters. In the numerical solution of the heat conductivity equation for snow and ice including a radiation source, a computational grid permitting to maintain spatial resolution of the temperature profiles in the snowice cover during its melting and growth was applied. Two variants of parameterization of solar radiation transfer in the sea ice were considered. The first version assumed exponential decay of radiation with the constant transmittance and attenuation coefficients. In the second one, a two-layer scheme of the solar radiation penetration into ice was used; it simulated the near-surface transition layer. Attenuation of intensity of solar radiation in the snow thickness was described by the Bouguer – Lambert law with the attenuation coefficient both as independent of the snow thermophysical characteristics and as represented by the function of its density. The numerical experiments with the purpose to reproduce seasonal evolution of the snow-ice cover thickness and its vertical temperature profile in the Taganrog Bay top part were performed for the winter season, 2016/17. Comparative analysis of the simulation results and the sea ice thickness values taken from the ESIMO ice maps made it possible to choose a combination of the model parameters that provides the best correspondence between the calculated and actual values. Conclusions. It is shown that in reproducing the seasonal changes in the ice cover thickness in the Taganrog Bay top part in winter, 2016/17, the choice of the transmittance and attenuation coefficients for white ice represented by the cloudiness functions, on the one hand, and the thickness of the layer with the most intense absorption of short-wave radiation ∼ 4 cm, on the other, turned out to be the most justified.

Methods for Assessing the State of Snow-Ice Cover

The development new methods for measuring the electrophysical and geometric parameters multilayer dielectric medium in order to identify their layers, as well as to detect inhomogeneities in them, is an urgent scientific task. Methods for assessing the state the snow-ice cover are proposed, based on the identification layers of the snow-ice cover by the dielectric permittivity obtained indirectly as a result inclined sounding of the underlying surface by an electromagnetic wave with vertical and horizontal polarization. Under normal sensing the underlying surface, in the form snow-ice cover, by radio waves with vertical and horizontal polarization, the obtained values the reflection coefficient from the boundary layers the received signals are identical. Oblique sensing by a vertically polarized wave in the range from 25 to 90 degrees leads to a sharp dip in the values the reflection coefficient from the boundary layers at certain angles, so for dry snow – 47…55°, dry firn – 55 … 58° and dry ice – 58…61°. These angles characterize the dielectric properties the layers (permittivity), which are explained by the complete polarization the reflected wave in a plane perpendicular to the plane incidence, since at this moment the vibrations the layer's electrons along the direction their movement do not lead to the emission electromagnetic waves in the direction the reflected wave (absent). The given estimated values the complex relative permittivity snow-ice cover as two component medium air and ice at a temperature from minus one to minus forty degrees, or three component medium air, ice and water at zero temperature are a sample for establishing the identity the characteristic properties layers. The purpose this article is to develop methods for assessing the state snow-ice cover used in determining the possibility performing a safe landing a helicopter – type aircraft on an unprepared site with snow-ice cover based on the identification the obtained characteristics snow-ice cover layers based on the results radar sensing with calculated data

The Speed Electromagnetic Wave Propagation in the Snow-Ice Underlying Surface

The results calculations the electromagnetic wave propagation velocity in the snow-ice cover depending on the density, the proportion liquid water content, and the propagation speeds the electromagnetic wave in dry snow, dry firn, and dry ice vary very markedly depending on the proportion liquid water content, the preferred orientation, and the shape ice and air structure are presented. The inclusions in the snow. The performed estimates the complex relative permittivity the medium that determines the speed propagation electromagnetic waves show a noticeable influence the density, the proportion liquid water content and the structure the underlying surface (snow, firn, ice), which allows identifying the layers the underlying surface in order to remotely determine the possibility landing a helicopter-type aircraft on an unprepared site with snow-ice cover. Shown, when the portion the water content in the medium is equal to zero, which is typical for negative temperatures, the speed propagation electromagnetic waves in the medium will depend on the density the medium and structure the dry ice in a small range of 1 m/μs temperature. In dry snow, vertically and horizontally elongated or spherical inclusions make a significant contribution to the change in the speed propagation the electromagnetic wave. At zero temperature, in the frequency range of 2 ... 8 GHz, the share water content in the medium, the density and structure the medium will play a determining role in the speed propagation an electromagnetic wave in the medium. The purpose this article is to determine the change ranges speed propagation electromagnetic waves in snow-ice the underlying surface depending on the density, structure, water content to restore the structure the snow and ice according to radar sensing, a more accurate determination the depth snow and thickness ice cover used in the assessment the possibility the safe landing an aircraft the helicopter type on an unprepared ground with snow-ice cover

Mathematical Model of Fluids Motion in Poroelastic Snow-ice Cover

The dynamics of a snow-ice cover is considered within the theory of poroelasticity. The snow-ice cover is modeled by a three-phase medium consisting of water, air and ice. The governing equations are the equations of mass conservation for each phase with phase transitions, the equations of conservation of phase momentum in the form of Darcy’s law, the equation of conservation of momentum of the whole system, the rheological equation for porosity and the equation of heat balance of snow. In the full formulation the liquid and air pressures are functions of the temperature and the corresponding densities, and the viscosity and compressibility coefficients of ice are functions of the temperature. The problem of two-dimensional nonstationary filtration of water in a thin poroelastic ice plate is considered in the model case. The solution is obtained in quadratures

Method for Remote State Identification Snow-Ice Cover by the Ratio of Fresnel Reflection Coefficients

Introduction. Currently, the development of safe helicopter landing systems as the most complex and dangerous stage of a flight is one of the priority tasks. A significant number of companies in Russia and abroad are engaged in its solution. Landing on unprepared (unequipped) sites with snow-ice cover may be caused by the need to deliver units, cargo and ammunition in combat conditions, search and rescue operations, evacuations of victims, etc. A key factor for a landing decision is information about the height of snow and about the depth of ice cover. In the paper remote identification of the state of snow-ice cover, excluding the need to present any person (crew member or rescue worker) on a landing site is proposed.Aim. To develop a method for the remote identification of the state of snow-ice cover used to determine the possibility of a helicopter - type aircraft safe landing on a reservoir with snow-ice cover.Materials and methods. Numerical simulation of echo signals Fresnel reflection coefficients polarization ratio was realized in MatLab. Vertical and horizontal polarizations in the range from 25 to 45 degrees were simulated.Results. Intervals of polarization relations correspond to the interval density of snow-ice layers for fixed angles. For example, when θ = 34 for dry snow ρds = 100…500 kg/m3 (ε'ds = 1.162…1.984) – Prm = 5.6915...3.3266, dry firn ρdf = 500…700 kg/m3 (ε'df = 1.984…2.51) – Prm = 3.3266...2.8311, dry ice ρdi = 700…913 kg/m3 (ε'di = 2.51…3.179) – Prm = 2.8311...2.4753. A layer reconstruction inverse problem was solved by indirect determining of complex relative permittivity of each successive underlying layer with 10-2 real part resolution. The identity of the obtained characteristics of snow-ice layers with calculated (standard) values was established.Conclusion. Remote identification of components of a snow-ice cover structure allows one to automate the process of evaluating of landing possibility. Thereby it reduces a decision-making time and increases a level of safety. In contrast to the known methods of identification of the surface layer the identification of multilayer medium layers was carried out.

Sea ice - atmosphere heat exchange during expedition “Transarctica-2019”

This paper describes the characteristics of atmospheric surface layer and heat balance components of snow-ice cover during drift of RV “Akademik Treshnikov” to the north of the archipelagos Franz Josef Land and Svalbard, in the area 80 - 82N, 30 - 45E, in comparison with observations at drifting station North Pole-35”, worked in the same area in April 2008, and “Ice Base Cape Baranova” in April 2019. Characteristics of atmospheric surface layer and the energy exchange processes during the drift of the expedition”Transarctica-2019” were significantly affected by the presence of clouds and the state of the ice cover. The influence of these factors led to a decrease in the radiative cooling of the surface, the formation of a warmer and wetter ABL and to a weakening of the turbulent exchange between the atmosphere and the snow-ice cover. Comparison of energy exchange characteristics, calculated for the Bolshevik Island (79° N) and for expedition “Transarctica 2019” area shows good agreement between the monthly averaged values and trends in heat fluxes, despite the fact that in the first case the underlying surface was sea ice cover, and in the second it was the land surface.

Dispersed Sedimentary Matter in the Marine Cryosystem: Snow–Drifting Ice–Icewater of the Arctic and Antarctic

A comparative description of sedimentary matter in the snow–ice cover of the Circumpolar Arctic and fast ice of the Antarctic is given. The main distribution patterns of dispersed sedimentary matter in the marine cryosystem of snow–sea ice–ice water of the Arctic and Antarctica are obtained. Sedimentary matter fluxes from the bottom of sea ice to the ocean bottom are calculated.

Vliyanie fazovogo sostava atmosfernyh osadkov na sezonnuyu evolyutsiyu snezhno-ledyanogo pokrova v vershine Taganrogskogo zaliva

Vliyanie fazovogo sostava atmosfernyh osadkov na sezonnuyu evolyutsiyu snezhno-ledyanogo pokrova v vershine Taganrogskogo zaliva

Influence of the Atmospheric Precipitation Phase Composition on Seasonal Evolution of Snow-Ice Cover in the Taganrog Bay Apex

Influence of the Atmospheric Precipitation Phase Composition on Seasonal Evolution of Snow-Ice Cover in the Taganrog Bay Apex

Concentration, composition and fluxes of dispersed sedimentary matter in the snow-ice cover of the near-pole Arctic region

Direct determinations of the dispersed sedimentary matter in the snow-ice cover near the North Pole are carried out. The composition of sedimentary material in the snow-ice cover was studied at the maximum for the high latitudes of the Northern Hemisphere distance from the continents, the vertical fluxes of matter from the under-ice layer were determined. These data were obtained using sediment traps. For snow and ice investigations melt waters of large volume were studied. It was found that dispersed sedimentary matter of aeolian genesis is of primary importance in snow and sea ice.

The North Pole Region: First Data on the Snow–Sea Ice–Ice Water Sedimentation System

The dispersed sedimentary material in the snow–ice cover near the North Pole was analyzed directly for the first time. The composition of sediments in the snow–ice cover and vertical fluxes of the material from the ice water layer were studied at the maximal distance for the Northern Hemisphere from the continents. The data were obtained by sedimentation traps (for water) and in large volumes of melt water (for snow and ice). It has been revealed that the dispersed sedimentary material of aeolian genesis plays the leading role in snow and sea ice.

ИСПОЛЬЗОВАНИЕ ГИДРОАКУСТИЧЕСКОГО ОБОРУДОВАНИЯ В ПЕРИОД ЛЕДОВОГО ПОКРЫТИЯ ВОДОЕМОВ

The paper presents the technique of hydroacoustic equipment operation for ichthyologic studies in the period of reservoir icing and minimum ambient temperature. The stages of carrying out a mobile sonar survey are described: creating a route with drilling holes in the ice and conducting the survey. For trouble-free operation of the software-technical hydroacoustic complex it has been proposed to use warm sledge-trailer for the snowmobile. A metal frame and a geotextile awning are installed on the top of the sledge-trailer to protect it against precipitation and low temperatures. Inside the sledge there is installed a gas-electric generator, a hydroacoustic complex; in addition, in the front part of the sledge there is a workplace for the operator making the survey. To discharge the exhaust gases of the generator there is an opening made in the sidewall of the awning; to prevent melting of generator sides there are set up asbestos sheets. The awning is located at the rear of the sledge and takes 2/3 of its length. In the middle of the sledge-trailer there is an amortization table, on which a hydroacoustic complex and a field tablet are installed. The table is attached to the sledge body with rubber ties, due to which shaking of the equipment is minimized when the snowmobile and sleigh are moving over the uneven snow-ice cover of the investigated water area. Due to the air-cooling of the generator under the awning, a positive temperature is maintained, which ensures the uninterrupted operation of computerized scientific research equipment and allows the operator to work comfortably. The described method was successfully tested in ichthyologic studies in the field at min ambient temperatures in the winter-spring period on the watercourses of the Tyumen region within the Tobolsk and Uvat regions in the period 2016-2018.

Problems of heat and mass transfer in the snow-ice cover

The snow-ice cover is considered as a three-phase continuous medium consisting of water, air, and ice. The mathematical model is based on the equations of mass conservation for each phase, the two-phase filtration equation for water and air in a movable porous ice skeleton, the rheological equation for porosity, the balance of forces and the equation of energy conservation for the ice-water-air system. The paper presents the results on analytic and numerical solutions of the problems under consideration.

Some engineering estimations of oil spill parameters in the marine environment

Estimation of the oil spill size at continuous spills on the moving sea surface or on the drifting ice field is the actual practical problem. Engineering estimation means the reduction of the hydrodynamic equations system to the balance of only two main forces that cause movement and resistance of the oil flow. From the simplified problem statement some practical relations were obtained for estimating the size of spill, including continuous oil spill with surface water currents presence, for spill onto porous snow-ice cover and onto the drifting ice cover. The obtained estimations can be used in more complicated models of oil spill transformation in the marine environment, primarily in the Arctic zone, and give basis for development of adequate responses on oil spills. The comparison of the obtained estimates with the self-similar solutions of the corresponding equations of motion of the spreading substance shows a satisfactory fit.