Fifty Years of Tidewater Glacier Surface Elevation and Retreat Dynamics along the South-East Coast of Spitsbergen (Svalbard Archipelago)

Tidewater glaciers on the east coast of Svalbard were examined for surface elevation changes and retreat rate. An archival digital elevation model (DEM) from 1970 (generated from aerial images by the Norwegian Polar Institute) in combination with recent ArcticDEM were used to compare the surface elevation changes of eleven glaciers. This approach was complemented by a retreat rate estimation based on the analysis of Landsat and Sentinel-2 images. In total, four of the 11 tidewater glaciers became land-based due to the retreat of their termini. The remaining tidewater glaciers retreated at an average annual retreat rate of 48 m year−1, and with range between 10–150 m year−1. All the glaciers studied experienced thinning in their frontal zones with maximum surface elevation loss exceeding 100 m in the ablation areas of three glaciers. In contrast to the massive retreat and thinning of the frontal zones, a minor increase in ice thickness was recorded in some accumulation areas of the glaciers, exceeding 10 m on three glaciers. The change in glacier geometry suggests an important shift in glacier dynamics over the last 50 years, which very likely reflects the overall trend of increasing air temperatures. Such changes in glacier geometry are common at surging glaciers in their quiescent phase. Surging was detected on two glaciers studied, and was documented by the glacier front readvance and massive surface thinning in high elevated areas.

Review of the Barents sea hydrological conditions

Based on more than 50 works published during the period 1946−2019, the chapter gives an overview of current ideas about bottom topography, large-scale circulation, currents and tides, water flows across borders, temperature and salinity distribution, water masses, frontal zones, seasonal and interannual variations in hydrological characteristics, stratification and ice conditions of the Barents Sea. Among the many classifications of water masses of the sea, the review gives preference to the most consistent and reasonable classification proposed by V. Ozhigin and V. Ivshin in 1999.

Fine-scale structures as spots of increased fish concentration in the open ocean

Oceanic frontal zones have been shown to deeply influence the distribution of primary producers and, at the other extreme of the trophic web, top predators. However, the relationship between these structures and intermediate trophic levels is much more obscure. In this paper we address this knowledge gap by comparing acoustic measurements of mesopelagic fish concentrations to satellite-derived fine-scale Lagrangian Coherent Structures in the Indian sector of the Southern Ocean. First, we demonstrate that higher fish concentrations occur more frequently in correspondence with strong Lagrangian Coherent Structures. Secondly, we illustrate that, while increased fish densities are more likely to be observed over these structures, the presence of a fine-scale feature does not imply a concomitant fish accumulation, as other factors affect fish distribution. Thirdly, we show that, when only chlorophyll-rich waters are considered, front intensity modulates significantly more the local fish concentration. Finally, we discuss a model representing fish movement along Lagrangian features, specifically built for mid-trophic levels. Its results, obtained with realistic parameters, are qualitatively consistent with the observations and the spatio-temporal scales analysed. Overall, these findings may help to integrate intermediate trophic levels in trophic models, which can ultimately support management and conservation policies.

The “U-Tube”: An improved aspirated temperature system for mobile meteorological observations, especially in severe weather

Obtaining quality air temperature measurements in complex mesoscale environments, such as thunderstorms or frontal zones, is problematic, and particularly challenging from a moving platform. For some time mobile weather platforms known as Mobile Mesonets (MMs) have used custom aspirated temperature shields. The original design was known as the “J-Tube”, which addresses some but not all of the unique problems associated with mobile temperature measurements. For VORTEX-2 2009, a second, well documented shield, the R.M. Young (RMY) 43408 was included but was also found to have certain shortcomings in some severe weather environments. Between the end of VORTEX2 2009 and the start of VORTEX2 2010, a third and new shield called the “U-tube” was designed, tested and installed.Reported here are the results of efforts to better characterize the J-Tube, RMY 43408, and the U-Tube. Several tests designed to isolate key aspects of a radiation shield’s performance, such as performance in rain, high solar radiation, varying wind conditions, and general response time were completed. A period of intercomparison between the three shields during the 2010 season of VORTEX 2 is also used to highlight each shield being used in “real world” conditions. Results indicate that the U-Tube has several significant advantages over the J-tube and 43408 in terms of aspiration rate, sampling efficiency, performance during rain, variable winds, and high solar radiation periods, as well as response time. Given these results, the U-tube should be utilized for mobile observations going forward.

UKRAINIAN DANCE CULTURE IN GEOGRAPHICAL AND ETHNOLOGICAL CONCERN ETHNOCHOREOGRAPHIC FRONTS

The problem of zoning of Ukrainian folk dance culture and its autochthonous and influential elements, which are especially active in the border areas with other ethnic groups and peoples, namely - ethnochoreographic fronts, in areas where the most intense processes of interaction and interpenetration of multinational dance segments. In the course of the research it was revealed that frontal zones can concern not only exclusively border areas (main meso-feature), but also function in much more localized territories of even one ethnic region (micro-feature), as well as cover large geographical areas or totally spread throughout territory of the country (macro-feature). An important factor is the intensity of the spread and assimilation of non-national or non-ethnic dance cultures, which can be measured in a few cases or be mass.

Time-dependent Plume Front Positioning and Its Dynamics Coupled With Seasonal River Efflux

The time-dependent plume front fluctuation concerning different tidal phases and its dynamics coupled with seasonal river efflux in the shelf off Kochi, south west coast of India, were investigated using Finite Volume Community Ocean Model (FVCOM). The region is linked with a monsoonal estuary, featured by mixed semi-diurnal tide (1 m) and exhibited a highly complicated plume pattern. The rivalry between river efflux with tidal phases create plume fronts in the shelf, whose gradients fortified or weakened by mixing dynamics. Eventhough the incessant river efflux in the summer monsoon impart significant momentum in the shelf, the range of frontal fluctuation was curtailed to 2 km by strong monsoon currents. During transient phase of the season (fall inter-monsoon), the tidal forcings on plume positioning overwhelm the shelf currents, such that the plume front fluctuate between 6-17 km (range increased to ~11 km) from the inlet. In low tides, the region near to the inlets was almost homogenized (Rd<1). While, it gets more stratified in high tides due to the transport of high saline ambient water towards the inlet and also by the decreasing kinetic energy (Rd>1). The location of frontal zones suitable for the propagation of nonlinear waves (F≤1)will change in respect to the competition between river efflux and tide-topography interaction. The strong stratified plume front regions with increased Brunt Vaisala Frequency (BVF) in summer monsoon behave as active zones of non linear wave propagation only when the plume front decelerates from supercritical to subcritical. During dry season, the F≤1 was satisfied at limited locations, but the absence of BVFmax zone (frequency >0.3 s-1) revealed that the amplitude of such nonlinear waves would be considerably small. The study divulge that tidally pulsating plume front fluctuates between 3-18 km from inlet and also highlights that the propagation of nonlinear waves with considerable amplitude will depend on both the plume front velocity and the Brunt Vaisala Frequency of the water column.

Variability of the frontal and eddies dynamics of the Kara Sea in the summer period

&lt;p&gt;The dynamics of fronts in the Arctic region is crucial in the formation and further variability of processes in the atmosphere and hydrosphere as a whole. However, the significant synoptic variability of the boundaries of the frontal zones and their characteristics determines the relevance of their study in a changing climate.&lt;/p&gt;&lt;p&gt;The article considers the relationship between the position of frontal zones and eddies structures in the Kara Sea in August and September 2019. To identify frontal zones, a single database is used, formed based on data on sea surface temperature from the Suomi NPP Viirs satellite, sea surface salinity from the NASA SMAP satellite and sea level from the international AVISO base. The cluster analysis method is used to detect frontal zones in the Kara Sea. To register the manifestations of eddies structures 358 Sentinel-1A and-1B satellite radar images obtained in the C-band at BB polarization and EW and IW shooting modes are analyzed.&lt;/p&gt;&lt;p&gt;It was possible to identify four classes of water in the sea area, one of which was identified as the River Plums frontal zone (RPFZ) the Ob and Yenisei. The maximum synoptic temperature gradient in the RPFZ region is 0.14&amp;#176;C/km, salinity is 0.12&amp;#8240;/km, and the level is 2 cm/km. It was found that the area of the RPFZ varies from 190K km&lt;sup&gt;2&lt;/sup&gt; in August to 221K km&lt;sup&gt;2&lt;/sup&gt; in September. During the research period, 1272 eddies structures were identified. It is shown that in August the number of eddies observed inside and within the boundaries of the frontal zones was twice as high as in September. In general, in the warm season of 2019 in the Kara Sea, most eddies occur in the RPFZ region. Thus, the number of eddies on the borders and inside the RPFZ in August is 30% more, and in September it is 20% more. The percentage difference is related to the wind impact over the Kara Sea, which is observed in September.&lt;/p&gt;&lt;p&gt;The analysis of the frontal zones and eddies in this work was supported by RFBR grant 20-35-90053.&lt;/p&gt;