Influence of snowpack internal structure on snow metamorphism and melting intensity on Hansbreen, Svalbard

This paper presents a detailed study of melting processes conducted on Hansbreen - a tidewater glacier terminating in the Hornsund fjord, Spitsbergen. The fieldwork was carried out from April to July 2010. The study included observations of meltwater distribution within snow profiles in different locations and determination of its penetration time to the glacier ice surface. In addition, the variability of the snow temperature and heat transfer within the snow cover were measured. The main objective concerns the impact of meltwater on the diversity of physical characteristics of the snow cover and its melting dynamics. The obtained results indicate a time delay between the beginning of the melting processes and meltwater reaching the ice surface. The time necessary for meltwater to percolate through the entire snowpack in both, the ablation zone and the equilibrium line zone amounted to c. 12 days, despite a much greater snow depth at the upper site. An elongated retention of meltwater in the lower part of the glacier was caused by a higher amount of icy layers (ice formations and melt-freeze crusts), resulting from winter thaws, which delayed water penetration. For this reason, a reconstruction of rain-on-snow events was carried out. Such results give new insight into the processes of the reactivation of the glacier drainage system and the release of freshwater into the sea after the winter period

Determining the Assumptions for the Selection of Measurement Methods for Products Manufactured with Incremental Methods

The article presents the method of determining the assumptions for the selection of measurement methods for products manufactured with the use of incremental processes. In the research area, an analysis of 3D printing methods was carried out in terms of the specificity of the additive process, the materials used, the possibility of process deformations, and the accuracy of technological machines. With regard to the measurement methods, the analysis covered the accuracy of the method, the speed of the measurements, the costs of the measurements and the applicability to additive manufactured products. As a result of the analysis, assumptions were made for the criteria for selecting measurement methods for incrementally manufactured objects. The accuracy of prototyping in incremental processes largely depends on the accuracy of their numerical models. Taking this into account, simulations and studies of program processing of data were also carried out, starting from the development of a 3D-CAD model, through the export of numerical models and the preparation of data for manufacturing and control-measurement processes

Snow distribution patterns on Svalbard glaciers derived from radio-echo soundings

The spatial distribution of snow thickness on glaciers is driven by a set of clima− tological, meteorological, topographical and orographic conditions. This work presents re− sults of snow accumulation studies carried out from 2006 to 2009 on glaciers of different types: valley glacier, ice plateau and ice cap. In order to determine snow depth, a shallow ra− dio echo−sounding method was used. Based on the results, the following snow distribution patterns on Svalbard glaciers have been distinguished: precipitation pattern, precipita− tion−redistribution pattern, redistribution pattern and complex pattern. The precipitation pattern assumes that the snow distribution on glaciers follows the altitudinal gradient. If the accumulation gradient is significantly modified by local factors like wind erosion and redeposition, or local variability of precipitation, the accumulation pattern turns into the precipitation−redistribution pattern. In the redistribution pattern, local factors play a crucial role in the spatial variability of snow depth. The complex pattern, however, demonstrates the co−existence of different snow distribution patterns on a single glacial object (glacier/ice cap/ice field)

Spatial variations in air temperature and humidity over Hornsund fjord (Spitsbergen) from 1 July 2014 to 30 June 2015

This article presents the variations in air temperature and humidity in the region of the Hornsund fjord for the period from 1 July 2014 to 30 June 2015. Based on measurements at 11 sites, it was established that significant topoclimatic differences were dependent on height above sea level, substrate type, distance from the sea, exposition, atmospheric circulation and the ice conditions. The thermal and humidity conditions of individual sites are presented in relation to the weather conditions at the Polish Polar Station in Hornsund (HOR). In the study period, the warmest annual mean air temperature occurred at Hyttevika (HYT), and the coldest on the summit of Fugleberget (FUG), respectively, +1.1°C and −3.7°C relative to HOR. Meanwhile, relative humidity differs from HOR values most strongly on Fugleberget, where it is greater by an average of 14%. Atmospheric circulation and ice cover were shown to have a significant impact on thermal and humidity conditions. The greatest spatial variations in air temperature (3.0°C) in Hornsund region (between HOR and FUG) occurred in winter during anticyclonic advection from the northern sector. The greatest difference in relative air humidity (20%) relative to HOR occurred in FUG in autumn during cyclonic advection from the eastern sector. The east–west thermal and humidity gradients along the fjord are more pronounced when sea ice is present. Differences in air temperature and relative humidity between the sites located in the inner (TRE) and outer parts of the fjord (HG4 and HYT) rose by about 2.0–2.5°C and 7–9%, respectively

Meteorological and biometeorological conditions in the Hornsund area (Spitsbergen) during the warm season

Meteorological and biometeorological conditions during the warm seasons (June-September) of 1979-2008 are described for the Hornsund area, Spitsbergen. The measurements were taken at four sites: at Hornsund, at the Hans Glacier (at its equilibrium line and in the firn section) and at the summit of Fugleberget. The variation of meteorological and biometeorological conditions was analysed in relation to altitude, distance from the sea and the ground type. In warm seasons, the air temperature at Hornsund was 2.2 °C higher on average than at the Hans Glacier (central section) and by 2.8 °C than at the Hans Glacier (firn section) and at Fugleberget. The average wind speed recorded at Hornsund was higher (0.6ms-1) than at the Hans Glacier and lower (0.9ms-1) than at Fugleberget. Four biometeorological indices were used: wind chill index (WCI), predicted insulation of clothing (Iclp), cooling power (H) and subjective temperature index (STI). The strongest thermal stimuli were observed on the Hans Glacier and in the upper mountain areas. The study has found a considerable degree of spatial variation between the meteorological elements investigated and the biometeorological indices in the Hornsund area. The impact of atmospheric circulation on meteorological elements and biometeorological indices is also presented. The mildest biometeorological conditions of the warm season found at Hornsund were associated with air masses arriving from the southwest and west

Analysis of the Impact of Geometry Modifications on the Fit of Splined Shaft Connections Manufactured Using Selected AM Methods

Broadly, understood additive manufacturing techniques expand the spectrum of production of machine parts that are used in various types of devices. However, the requirements to ensure dimensional and shape accuracy require the determination of appropriate material allowances or clearances to enable correct assembly. For the above reasons, the study presents an analysis of the impact of the assumed geometry modifications on the possibility of assembling a splined connection manufactured using selected AM techniques. The work focused on the analysis of changes in geometry resulting from the technology used. Using the Atos II Triple Scan optical measurement system and Gom Inspect software, the possibility of installation was determined for four variants of the splined shaft connection geometry, resulting from the technologies used

Climatic conditions at Arctowski Station (King George Island, West Antarctica) in 2013–2017 against the background of regional changes

This paper provides an overview of the results of research on changes in ground temperature down to 50 cm depth, on the Kaffiøyra Plain, Spitsbergen in the summer seasons. To achieve this, measurement data were analysed from three different ecotopes (CALM Site P2A, P2B and P2C) – a beach, a moraine and tundra – collected during 22 polar expeditions between 1975 and 2014. To ensure comparability, data sets for the common period from 21 July to 31 August (referred to as the “summer season” further in the text) were analysed. The greatest influence on temperature across the inves− tigated ground layers comes from air temperature (correlation coefficients ranging from 0.61 to 0.84). For the purpose of the analysis of the changes in ground temperature in the years 1975–2014, missin

Surface and bed morphology of hansbreen, a tidewater glacier in Spitsbergen

Hansbreen, a medium size tidewater glacier in Southern Spitsbergen (Svalbard) is one of the most intensively studied glaciers in the Arctic. This work presents new digital elevation models of its surface and basal topography based on data collected during GPS/GPR campaigns conducted in the spring seasons of 2005 and 2008, as well as on other recent topographic/bathymetric sources. The mean thickness of the glacier is calculated as 171 m and its volume is estimated to be 9.6 (±0.1) km3. The main feature of the bedrock morphology is a vast depression that is overdeepened below sea level and extends as far as 11 km upstream from the glacier front. This depression is divided into four individual basins by distinct sills that are related to the main geological/tectonic features of the area. The bedrock morphology affects considerably the glacier's surface topography. The influence of bedrock and surface relief on the subglacial drainage system geometry is discussed. Vast depressions on the glacier surface favor concentration of meltwater and development of moulin systems

Variability of temperature and thickness of permafrost active layer at coastal sites of Svalbard

We present the variability of the thermal state and thickness of permafrost active layer at the raised marine beaches in Svalbard. The investigations were carried out using direct probing, thaw tube, ground temperature and radar soundings at Holocene strand plains 10-20 m a.s.l. in Fuglebergsletta (SW Spitsbergen) and at the shore of Kinnvika Bay (Nordaustlandet). Their results were compared to those obtained at other coastal sites in Svalbard. The ground temperature measurements were conducted in 2009 on August, recognized as the standard month for the maximum thawing during the last decade. The studied sites are typical for close to extreme active layer conditions on Svalbard. In Hornsund, the thawing depth exceeded 2 m, while in Kinnvika the active layer was thinner than 1 m. In Svalbard, the depth of thawing decreases generally from south to north and from the open sea coast to the central parts of islands. These differences are the consequence of diverse climatic conditions strongly determined by the radiation balance modified by a number of regional (e.g. ocean circulation) and local (e.g. duration of snow deposition) conditions

A study of a parametric method for the snow reflection coefficient estimation using air-coupled ultrasonic waves

In this paper, a method for estimating snow pressure reflection coefficient based on non-contact ultrasound examination is described. A constant frequency and air-coupled ultrasound pulses were used in this study, which incorporates a parametric method for reflected energy estimation. The experimental part was carried out in situ in the Antarctic, where the snow parameters were measured along with meteorological data. The proposed method represents a promising alternative for estimating the snow-water equivalent, since it uses a parametric approach, which does not require measurements of absolute values for acoustic pressure