Klucz do zrozumienia Arktyki. Fiord jako ogniwo integrujące ocean, ląd i atmosferę

Fjords are long and deep bays of the glacial origin. Thanks to their extent into the interior they effectively contributed settlement process. Currently fjords are economically exploited by the wide scope of activities related to marine economy and tourism. Due to sea – atmosphere – land interactions, fjords become the subject of interdisciplinary studies on feedbacks between the individual environment components. Particular scientific interest is focused on the arctic fjords due to their still unaffected nature and climate changes 2–4 times faster in polar areas than in other regions of the world. Such kind of studies devoted to the observations of the fjords in Svalbard were carried out within AWAKE international project and are continued with AWAKE2. In particular, the investigations concern the frequency and results of the warm Atlantic water inflow into the fjords. Glaciers terminating into fjords influenced by environmental changes, since the end of 19th century are in permanent recession. Glaciers supply increased amount of freshwater coming from both the melting and the calving

The Thickness of Talus Deposits in the Periglacial Area of SW Spitsbergen (Fugleberget Mountainside) in the Light of Slope Development Theories

Periglacial slopes are susceptible to recent climate change. The rate of morphogenetic processes depends on numerous factors. The most important of these is the warming of the air and ground, increased precipitation (extreme rainfall in particular), and the rate of snow cover decay. The dynamics of these processes may effectively modify contemporary slope development models. The paper shows the structure of selected talus slopes on a Fugleberget mountainside, based on field observations and radar (GPR) soundings. The results are then compared to classical slope models. The radar survey in April and May 2014 used a RAMAC CU II Malå GeoScience system equipped with a 30 MHz RTA antenna (Rough Terrain Antenna). Five GPR profiles of different lengths were obtained along the talus axes, transversally on Fugleberget and partly on the Hansbreen lateral moraine. According to the radar soundings, the maximum thickness of the debris deposits is 25–30 m. The thickness of the weathered material increases towards the talus cone’s terminal part, and debris deposits overlap marine sediments. The talus slopes’ morphometry shows that their current forms differ from standard slope models, which may be due to the significant acceleration of geomorphic processes resulting from climate change, including rapid warming in the last four decades

Role of discrete water recharge from supraglacial drainage systems in modeling patterns of subglacial conduits in Svalbard glaciers

As the behavior of subglacial water plays a determining role in glacier dynamics, it requires particular attention, especially in the context of climate warming, which is increasing ablation and generating greater amounts of meltwater. On many glaciers, water flowing from the glacier’s surface is the main source of supply to the subglacial drainage system. This system is largely influenced by the supraglacial drainage system, which collects meltwater and precipitation and rapidly delivers it to discrete points in the glacier bed via moulins and crevassed areas, called water input areas (WIAs). Models of patterns of subglacial conduits mainly based on the hydrological potential gradient are still regularly performed without taking into account the supraglacial drainage system. We modeled the pattern of subglacial channels in two glaciers located in Svalbard, the land-terminating Werenskioldbreen and the tidewater Hansbreen during the 2015 melt season.We modeled a spatial and a discrete water recharge in order to compare them. First, supraglacial catchments were determined for each WIA on a high-resolution digital elevation model using the standard watershed modeling tool in ArcGIS. Then, interpolated water runoff was calculated for all the main WIAs. Our model also accounts for several water pressure conditions. For our two studied glaciers, during the ablation season 2015, 72.5% of total runoff was provided by meltwater and 27.5% by precipitation. Changes in supraglacial drainage on a decadal timescale are observed in contrast to its nearly stable state on an annual timescale. Nevertheless, due to the specific nature of those changes, it seems to have a low impact on the subglacial system. Therefore, our models of subglacial channel are assumed to be valid for a minimum period of two decades and depend on changes in the supraglacial drainage system. Results showed that, for Svalbard tidewater glaciers with large crevassed areas, models of subglacial channels that assume spatial water recharge may be somewhat imprecise but are far from being completely incorrect, especially for the ablation zone. On the other hand, it is important to take discrete water recharge into account in the case of landterminating Svalbard glaciers with limited crevassed areas. In all cases, considering a discrete water recharge when modeling patterns of theoretical subglacial channels seems to produce more realistic results according to current knowledge

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)

Glacier facies of Vestfonna (Svalbard) based on SAR images and GPR measurements

The warming climate of the Arctic affects the mass budget of glaciers, and changes in the distribution of glacier facies are indicative of their response to climate change. The glacial mass budget over large land ice masses can be estimated by remote sensing techniques, but selecting an efficient remote sensing method for recognizing and mapping glacier facies in the Arctic remains a challenge. In this study, we compared several methods of distinguishing the facies of the Vestfonna ice cap, Svalbard, based upon Synthetic Aperture Radar (SAR) images and terrestrial high frequency Ground Penetrating Radar (GPR) measurements. Glacier zones as determined using the backscattering coefficient (sigma0) of SAR images were compared against GPR data, and an alternative application of Internal Reflection Energy (IRE) calculated from terrestrial GPR data was also used for differentiating the extent of glacier facies. The IRE coefficient was found to offer a suitable method for distinguishing glacier zones and for validating SAR analysis. Furthermore, results of analysis of fully polarimetric Phased Array type Lband Synthetic Aperture Radar (ALOS PALSAR) and European Remote Sensing Synthetic Aperture Radar (ERS-2 SAR) images were compared with the IRE coefficient classification. Especially promising method is H-α segmentation, where the glacier zone boundaries corresponded very well with both GPR visual interpretation and IRE classification results. The IRE coefficient's simplicity of calculation makes it a good alternative to the subjective GPR visual interpretation method, where results strongly depend on the operator's level of experience. We therefore recommend for GPR profiles to be used for additional validation of SAR image analysis in studies of glacier facies on the High Arctic ice masses

Distribution of snow accumulation on some glaciers of Spitsbergen

We describe the spatial variability of snow accumulation on three selected gla− ciers in Spitsbergen (Hansbreen, Werenskioldbreen and Aavatsmarkbreen) in the winter seasons of 1988/89, 1998/99 and 2001/2002 respectively. The distribution of snow cover is determined by the interrelationships between the direction of the glacier axes and the domi− nant easterly winds. The snow distribution is regular on the glaciers located E−W, but is more complicated on the glaciers located meridionally. The western part of glaciers is more predisposed to the snow accumulation than the eastern. This is due to snowdrift intensity. Statistical relationships between snow accumulation, deviation of accumulation from the mean values and accumulation variability related to topographic parameters such as: alti− tude, slope inclination, aspect, slope curvature and distance from the edge of the glacier have been determined. The only significant relations occured between snow accumulation and altitude (r = 0.64–0.91)

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

Current views on treatment of the ovarian granulosa-cell tumor

Summary The granulosa-cell tumor ( folliculoma ) is a rare type of ovarian neoplasm, accounting for 5% of all cases [1]. It is the most common type of sex cord-stromal tumors, diagnosed in 70% of cases. The granulosa-cell tumor is a hormone active one, originating from granulosa cells which produce estradiol. Overproduction of estradiol is helpful in the diagnosis of the tumor because of its numerous symptoms. There are two types of folliculoma: juvenile (5%) and adult (95%). The juvenile type is mostly recognized ( 90% ) in FIGO I stage and has a better prognosis. Operation is often a sufficient way of treatment in this group [1]. Tumors in higher stages are more aggressive and must be treated further[ 2]. The adult folliculoma is more aggressive in its nature. Patients with the disease diagnosed in higher stages must be treated by adjuvant radiotherapy or chemotherapy[1]. Recurrence appears often many years after the treatment and has high mortality. Many old ( platinum) and new (taxans) agents are active when used in treatment of this type of tumor. Randomized study must be made to establish standard therapy of granulosa-cell tumor. Currently, the most frequent way of treatment is chemotherapy with BEP (Blemycyna, Etopozyd, Cisplatyna)

Variability of the snow avalanche danger in the Tatra Mountains during the past nine decades

In order to recognise the variability of the snow avalanche danger in the Tatra Mountains, the danger levels on consecutive days with snow cover over the last nine decades were calculated. To accomplish this task, the longest series of meteorological data were used from the Tatras along with an empirical method for determining the regional avalanche danger on the basis of elementary meteorological data. The results point to the fact that over the last 25 years the number of days with a level 2 avalanche danger significantly decreased, whereas the number of days with level 1 increased. This should result in a decreasing trend in the incidence of small and medium-sized natural avalanches. In the structure of snow cover, the percentage of melt forms might increase. However, this should not correlate with a significant increase in wet-snow avalanches, because the number of days with wet snow also reduces. The contemporary changes in the snow conditions and avalanche danger in the subalpine belt of the Tatras have been primarily associated with an increase in the air temperature (shorter winters and less snow)