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The Arctic region plays an important role in the global climate system. To promote the application of Medium Resolution Spectral Imager-II (MERSI-II) data in the ice surface temperature (IST) inversion, we used the thermal infrared channels (channels 24 and 25) of the MERSI-II onboard Chinese FY-3D satellite and the thermal infrared channels (channels 31 and 32) of the Earth Observing System (EOS) Moderate-Resolution Imaging Spectroradiometer (MODIS) onboard the National Aeronautical and Space Administration (NASA) Aqua satellite for data analysis. Using the Observation–Observation cross-calibration algorithm to cross-calibrate the MERSI and MODIS thermal infrared brightness temperature (Tb) data in the Arctic, channel 24 and 25 data from the FY-3D/MERSI-II on Arctic ice were evaluated. The thermal infrared Tb data of the MERSI-II were used to retrieve the IST via the split-window algorithm. In this study, the correlation coefficients of the thermal infrared channel Tb data between the MERSI and MODIS were >0.95, the mean bias was −0.5501–0.1262 K, and the standard deviation (Std) was <1.3582 K. After linear fitting, the MERSI-II thermal infrared Tb data were closer to the MODIS data, and the bias range of the 11 μm and 12 μm channels was −0.0214–0.0119 K and the Std was <1.2987 K. These results indicate that the quality of the MERSI-II data is comparable to that of the MODIS data, so that can be used for application to IST inversion. When using the MERSI thermal infrared Tb data after calibration to retrieve the IST, the results of the MERSI and MODIS IST were more consistent. By comparing the IST retrieved from the MERSI thermal infrared calibrated Tb data with MODIS MYD29 product, the mean bias was −0.0612–0.0423 °C and the Std was <1.3988 °C. Using the MERSI thermal infrared Tb data after calibration is better than that before calibration for retrieving the IST. When comparing the Arctic ocean sea and ice surface temperature reprocessed data (L4 SST/IST) with the IST data retrieved from MERSI, the bias was 0.9891–2.7510 °C, and the Std was <3.5774 °C. [ABSTRACT FROM AUTHOR]

All materials have different and unique thermal properties that determine how the temperature changes when a material is subjected to a temperature difference. This study was intended to investigate the thermal properties of a polymer called Polyurethane, focusing on anti-seepage and anti-abrasion polyurethane. The thermal conductivity and heat transfer coefficient of cold polyurethane specimens have been calculated by capturing the infrared signature using a FLIR T1030Sc Infrared camera and comparing the results with simulated results. The simulations were carried out in MATLAB®, and the solution is based on the Heat equation. This paper describes the driving mechanisms behind the Heat equation and how the approximated solution to the Heat equation is obtained by discretizing through a forward-time central-space (FTCS) finite-difference method. The results reveal that the heat transfer coefficient for anti-abrasion Polyurethane is almost four times that for anti-seepage Polyurethane. The thermal conductivity for the respective has a difference of a factor of two. A good agreement between the experimental and the numerical study was achieved. This study is helpful for the potential use of polyurethane material in Arctic regions either as a coating material for pipes or as a sealant in the oil and gas industry. [ABSTRACT FROM AUTHOR]

The values of the snow and soil thermal conductivity, ksnow and ksoil, strongly impact the thermal regime of the ground in the Arctic, but very few data are available to test model predictions for these variables. We have monitored ksnow and ksoil using heated needle probes at Bylot Island in the Canadian High Arctic (73° N, 80° W) between July 2013 and July 2015. Few ksnow data were obtained during the 2013-2014 winter, because little snow was present. During the 2014-2015 winter ksnow monitoring at 2, 12 and 22 cm heights and field observations show that a depth hoar layer with ksnow around 0.02Wm-1 K-1 rapidly formed. At 12 and 22 cm, wind slabs with ksnow around 0.2 to 0.3Wm-1 K-1 formed. The monitoring of ksoil at 10 cm depth shows that in thawed soil ksoil was around 0.7Wm-1 K-1, while in frozen soil it was around 1.9Wm-1 K-1. The transition between both values took place within a few days, with faster thawing than freezing and a hysteresis effect evidenced in the thermal conductivity- liquid water content relationship. The fast transitions suggest that the use of a bimodal distribution of ksoil for modelling may be an interesting option that deserves further testing. Simulations of ksnow using the snow physics model Crocus were performed. Contrary to observations, Crocus predicts high ksnow values at the base of the snowpack (0.12-0.27Wm-1 K-1) and low ones in its upper parts (0.02-0.12Wm-1 K-1). We diagnose that this is because Crocus does not describe the large upward water vapour fluxes caused by the temperature gradient in the snow and soil. These fluxes produce mass transfer between the soil and lower snow layers to the upper snow layers and the atmosphere. Finally, we discuss the importance of the structure and properties of the Arctic snowpack on subnivean life, as species such as lemmings live under the snow most of the year and must travel in the lower snow layer in search of food. [ABSTRACT FROM AUTHOR]

Nowadays a lot of ports and quays are constructed in the areas with seasonal ice cover. Ice can prevent marine operations and lead to lost of time and therefore lost of money. One of the solutions to prevent ice adfreeze to marine and ocean structures is heating of the quayage. Heating prevents ice formation and provides acceptable conditions for loading/unloading of the vessels. The process and technology for this process are not properly described in the existing literature. However, estimation of the amount of the heat which is needed to prevent ice formation is vitally important and influences the entire construction project. The amount of heat can be estimated by a numerical simulation. The work also proposes the mathematical way for rough estimation of the power needed to prevent freezing in the ice. Mathematical estimation correlated with the numerical estimation. Calculations are made for possible time for the vessel to spend in the port – two weeks of freezing during −10 °C (140 freezing-degree-days). [ABSTRACT FROM AUTHOR]

We use a 1-D model to study how salinity evolves in Arctic sea ice. To do so, we first explore how sea-ice surface melt and flooding can be incorporated into the 1-D thermodynamic Semi-Adaptive Multi-phase Sea-Ice Model (SAMSIM) presented by Griewank and Notz (2013). We introduce flooding and a flushing parametrization which treats sea ice as a hydraulic network of horizontal and vertical fluxes. Forcing SAMSIM with 36 years of ERA-interim atmospheric reanalysis data, we obtain a modelled Arctic seaice salinity that agrees well with ice-core measurements. The simulations thus allow us to identify the main drivers of the observed mean salinity profile in Arctic sea ice. Our results show a 1.5–4 g kg–1 decrease of bulk salinity via gravity drainage after ice growth has ceased and before flushing sets in, which hinders approximating bulk salinity from ice thickness beyond the first growth season. In our simulations, salinity interannual variability of first-year ice is mostly restricted to the top 20 cm. We find that ice thickness, thermal resistivity, freshwater column, and stored energy change by less than 5% on average when the full salinity parametrization is replaced with a prescribed salinity profile. [ABSTRACT FROM AUTHOR]

Global warming may induce an increase of active layer thickness in the Arctic region. The freezing and thawing of the active layer can damage infrastructures such as roads, railways, and embedded pipe lines in cold regions. A few methods, however, have been proposed to characterize the active layer. The objective of this study is to evaluate the characteristics of the active layer by laboratory and field tests, especially using the instrumented dynamic cone penetrometer (IDCP). Geographical and geological characteristics of Ny-Alesund, Svalbard are introduced, and the geotechnical properties, microstructure observations, and thermal properties of the Ny-Alesund soils are investigated. In addition, subsurface temperatures monitored for a year are discussed. The IDCP, which is able to measure the energies transferred into the rod head and the cone tip, is applied to the evaluation of the strength variation and the thickness of the active layer in Ny-Alesund. During dynamic penetration tests, the IDCP can produce profiles of the corrected cone tip resistance as well as the dynamic cone penetration index (DCPI). The results show that the active layer thickness estimated from the DCPI and corrected cone tip resistance profiles is approximately 1700mm. Furthermore, the bottom of the active layer significantly corresponds to that estimated by the maximum ground temperature profile with a soil thermal diffusivity of 5.5·10−7 m2·s−1. This study represents the characteristics of Ny-Alesund soils investigated with a variety of laboratory tests, and suggests that the IDCP may be effectively used for active layer characterization. [ABSTRACT FROM AUTHOR]

The article discusses a paper which examines the climatic and related environmental changes in the Arctic regions and its impacts in Eurasia, as well as to human activities, economic development, and national security. It outlines various manifestations of Arctic climate warming such as the reduction of the permafrost zone and reduced Arctic ice cap thickness. It suggests that climate change directly affect Eurasia and thus need to respond economically and socially to environmental changes.

Important environmental parameters in arctic periglacial landscapes (i.e. permafrost temperature, active-layer depth, soil moisture, precipitation, vegetation cover) will very likely change in a warming climate. The thawing of permafrost, especially, might cause massive landscape changes due to thermokarst and an enhanced release of greenhouse gasses from the large amounts of carbon stored in frozen deposits, resulting in positive climate-warming feedback. For the identification, mapping, and quantification of such changes on various scales up to the entire circum-Arctic, remote sensing and spatial data analysis are essential tools. In this study an extensive field-work dataset including spectral surface properties, vegetation, soils, and geomorphology was acquired in the largest Arctic delta formed by a single river, the Siberian Lena River Delta. A portable field spectrometer (ASD FieldSpec Pro FR®) was used for spectral surveys of terrain surfaces, and optical satellite data (Landsat Enhanced Thematic Mapper (ETM+), CHRIS-Proba) were used for the characterization, manual mapping, and automatic classification of typical periglacial land-cover units in the Lena Delta. Qualitative data from soils, vegetation, soil moisture, and relief units were correlated with the field-spectral data and catalogued for a wide variety of surface types. The wide range of micro- and meso-scale variations of periglacial surface features in the delta results in distinctive spectral characteristics for different land-cover units. The three main delta terraces could also be spectrally separated and characterized. The present dataset provides a basis for further spectral data acquisitions in the Lena Delta and for comparisons with periglacial surfaces from other regions. [Copyright &y& Elsevier]

Permafrost soils in boreal and Arctic ecosystems store almost twice as much carbon as is currently present in the atmosphere. Permafrost thaw and the microbial decomposition of previously frozen organic carbon is considered one of the most likely positive climate feedbacks from terrestrial ecosystems to the atmosphere in a warmer world. The rate of carbon release from permafrost soils is highly uncertain, but it is crucial for predicting the strength and timing of this carbon-cycle feedback effect, and thus how important permafrost thaw will be for climate change this century and beyond. Sustained transfers of carbon to the atmosphere that could cause a significant positive feedback to climate change must come from old carbon, which forms the bulk of the permafrost carbon pool that accumulated over thousands of years. Here we measure net ecosystem carbon exchange and the radiocarbon age of ecosystem respiration in a tundra landscape undergoing permafrost thaw to determine the influence of old carbon loss on ecosystem carbon balance. We find that areas that thawed over the past 15 years had 40 per cent more annual losses of old carbon than minimally thawed areas, but had overall net ecosystem carbon uptake as increased plant growth offset these losses. In contrast, areas that thawed decades earlier lost even more old carbon, a 78 per cent increase over minimally thawed areas; this old carbon loss contributed to overall net ecosystem carbon release despite increased plant growth. Our data document significant losses of soil carbon with permafrost thaw that, over decadal timescales, overwhelms increased plant carbon uptake at rates that could make permafrost a large biospheric carbon source in a warmer world. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess initial effects of warming on the CO2 balance of a lichen-rich dwarf shrub tundra, a widespread but little studied ecosystem type in the Arctic. We analyzed whole ecosystem carbon exchange rates as well as nutrient dynamics, microbial and plant community composition and biomass after 2 years of experimental temperature increase. Plant biomass increased significantly with warming, mainly due to the strong response of lichens, the dominant plant group within this ecosystem. Experimental warming also increased soil nitrogen pools and nitrogen turnover rates. Major changes in soil microbial and plant composition, however, were not detected. Although experimental warming increased gross ecosystem productivity, the higher plant biomass did not compensate for the much greater increase in C losses. Ecosystem respiration and net ecosystem CO2 losses were significantly higher in warmed plots compared to control ones. We suggest that this was due to increased soil respiration, since soil carbon pools were lower in warmed soils, at least in the upper horizons. Our study thus supports the general hypothesis that tundra ecosystems turn from a carbon sink to a carbon source when temperatures increase in the short-term. Since lichens, which produce low quality litter, increased their biomass significantly with warming in this specific ecosystem type, CO2 losses may slow down in the long-term. [ABSTRACT FROM AUTHOR]

• Effect of waste perlite and activation by jet mill on structure of cement paste is revealed. • Decrease in density and heat conductivity of plaster mortar is established. • Standard physical properties of plaster mortars are due to improved structure of cement paste. • The superplasticizer reduce the segregation of the cement-perlite mix. • Technology for production of low-density plaster thermal insulation mix was developed. The direction of many leading states is aimed at the development of the Arctic, so the creation of new generation thermal insulation materials is given priority. The novelty of the paper is to identify the scientific patterns of the influence of binder composites based on Portland cement and waste of expanded pearlite sand during joint jet grinding on the hydration mechanism and the structure of the plaster mortar. The grinding of heat-insulating binders in ball, vibration and vortex jet mills was studied. The features of hydrated phase formation and hardening of modified binders were studied taking into account the chemical, structural and morphological features of perlite wastes. Besides, the microstructural, morphological and thermal properties of the hardened binders at 28 days of curing were determined. For the first time, the scientific data were obtained on the properties of modified heat-insulating binder and plaster mortars based on it, obtained by mechanochemical jet activation. The results indicate that the jet activation of the modified binder based on Portland cement, waste from the production of expanded perlite sand and superplasticizer, contributes to the improvement of the physicomechanical properties of 28-days hardened binder: the compressive strength of 84.2 MPa and density of 2100 kg/m3. Based on the developed modified binder, the effective heat-insulating plaster mortars with heat conductivity of 0.051–0.059 W/(m·°C), a density of 240–260 kg/m3 and a compressive strength of 1.3–1.43 MPa were obtained, which meets the requirements. Technological route for the production of low-density plaster thermal insulation mix was developed. [ABSTRACT FROM AUTHOR]