Three types of rock glaciers (moraine, cirque and subslope ones) were distinguished in northwestern Wedel Jarlsberg Land. Subslope rock glaciers were found different from nival moraines. A development of subslope and fossil cirque rock glaciers was connected with the older Holocene whereas of active cirque and moraine rock glaciers with the Little Ice Age.
Spitsbergen glaciers react rapidly to changes in the polar environment, which is expressed in differences in extent of their fronts and surface geometry. The Scott Glacier, which is situated in the NW part of Wedel Jarlsberg Land, is an example of the glacier that has undergone almost continuous recession since the Little Ice Age, interrupted by surges. The variations in recession are characterised based on multiannual data with particularly consideration of the period 1990–2005 and the season 2005/2006. Acceleration of front recession and lowering the surface was found only within the tongue up to a height of about 220 m a.s.l. Whereas, in the area situated in the zone of rock steps and above in the ablation zone, the change of glacier surface ablation (Dh) has been recorded compared to the mean annual recession for the period 1990–2005. Moreover, for the upper firn field, the positive surface ablation (DhS7 = +0.19 m) was observed. As the result of progressive reduction of the Scott Glacier mass, with the participation of other factors (bedrock relief among others), new surfaces of roche moutonnée are uncovering particularly in the tongue zone.
Traditional mass balance measurements by stake readings and snow surveying have been conducted annually since 1996 on the Waldemar Glacier (= Waldemarbreen) in northwest Spitsbergen, Svalbard. Several indirect methods were also used for estimating its mass balance. These methods were divided into two major groups: climatological and geodetic. A comparison of the latest map (2000) with that of 1978 and climatological records enable us to calculate the change in the mass balance of Waldemarbreen over 34 years. These methods include air temperature and degree-day (PDD) models. The average mass balance of Waldemarbreen, computed by climatological methods, was -0.42 m a-1 of water equivalent (w.e.) for the period 1970-2004, and -0.51 m w.e. for 1996-2004. These balances were compared with the glaciological balance for the period 1996-2004, -0.53 m w.e.. The mass balance was also computed using geodetic method, giving -0.52 m of w.e. from 1978 to 2000. It is suggested that, from these results, the approach used for Waldemarbreen might be also useful for estimation the mass balances of other small Svalbard glaciers which terminate on land.
Although the terrestrial marginal zones of some glaciers on Spitsbergen are relatively well described, we are largely ignorant about the morphology of their submarine forefields. Initial reconnaissance of the forefields of the Aavatsmark and Dahl glaciers in the Kaffiøyra region and soundings made in that of the Hans Glacier (southern Spitsbergen ) indicate the occurrence of sea-floor push-moraines which can be as much as 3 m high. Their lateral separation is considered to denote annual recession rates. They appear to result from cyclical annual advances of ice-cliffs during winters when the deposits are risen up at the contact of the ice with the sea-floor. The development of the major forms may be related to surge. There is some evidence that certain elements in the sea-bed morphology date from the Little Ice Age (LIA).
The differentiation of the isotopic composition of glacial water in some Hornsund glaciers was found to depend on its position with respect to the firn line, situation in the circulation system and on seasonal variations of air temperature. Intensive ice thawing in the ablation zone is marked by decreased values of the tritium content in the discharge of the glacier, whereas water from thawing snow nad firn increases these values. The isotopic differentiation which occures in waters in the main flow systems indicates the magnitude of the shares of water from thawed ice firn and snow in the total drainage of the glacier.
The radar device for measurement of thickness and structure of "warm" glaciers was used in this work. The measurement of thickness of dielectric is based here on the examination of transit time of hight frequency electromagnetic pulse throught the measured stratum. A total ice volume of "warm" glaciers is in the melting temperature here. Such glaciers are characterized by a large number of internal structure defects. The electromagnetic wave reflections are caused not only b the glacier base but, additionally by ice crevasses, more imbided water layers and by all other defects of the internal glacier structure, too. The simple statistical method was elaborated for differentiation of essential layers reflections from random reglections caused by less extented objects. This method was used to obtain the two transversal profiles of the Hans Glacier (South Spitsbergen).
Arctic glaciers respond quickly to climatic conditions, which is why they play a special role as climate warming indicators. Studying them in the long term is the key to understanding future global environmental changes.
The ablation of glaciers is an important factor in energy exchange between the atmosphere and land ice masses. The dynamics of ablation closely reflects climate changes and is important for the estimation of the outflow of meltwater, which, having penetrated a glacier to bedrock, stimulates its velocity by increasing basal sliding. More detailed studies using automatic weather stations (AWS) and the calculation of the energy budget are rarely conducted on small glaciers. The mass balance of the Hans Glacier has been monitored since 1989. Its intensified monitoring using AWS began in 2003. The results show that ablation depends more evidently on the daily mean and maximum air temperature and wind speed than on total and net radiation. Ablation, both that controlled by sonic height ranger and that measured manually on stakes, was compared with the values calculated on the basis of energy flux formulas applied by Oerlemans (2000). The statistical results allowed us to construct empirical equations, which in turn enabled us to compute the course and total ablation during the summer seasons. It can be described on the basis of two primary meteorological elements (air temperature and wind speed), as recorded in the station representing the regional area (Hornsund) or measured in situ on the glacier. Standard measurements of ablation from the years 1989-2004 were used to verify empirical model. The computed mean value of summer ablation for 1989-2004 was calculated at 1.35 m , differing from real measurements by only 10% (with SD = 0.18). The results obtained illustrate that an empirical equation can be applied in time series analyses. A regional ablation model enables us to investigate the mass-balance history of glaciers on the basis of meteorological data.
The near-surface ice thermal structure of the Waldemarbreen, a 2.5-square km glacier located at 78°N 12°E in Spitsbergen, Svalbard , is described here. Traditional glaciological mass balance measurements by stake readings and snow surveying have been conducted annually since 1996. The near-surface ice temperature was investigated with automatic borehole thermistors in the ablation and accumulation areas in 2007-2008. The mean annual surface ice temperatures (September-June) of the ablation area were determined to be -4.7°C at 1 m depth and -2.5°C at 9 m . For the accumulation area, they were -3.0°C at 2 m , and -2.3°C at 10 m depth between September and August. On the Waldemarbreen, at 10 m depth, the mean annual near-surface ice temperature was 4.0°C above the mean annual air temperature in the accumulation area. The Waldemarbreen may thus be classified as a polythermal type with cold ice which is below the pressure melting point and a temperate ice layer in the bottom sections of the glacier and with a temperate surface layer only during summer seasons. At a depth of 10 m , temperatures are of the order of -2°C to -3°C.
The purpose of this study is to describe the current state of tidewater glaciers in Svalbard as an extension of the inventory of Hagen et al. (1993). The ice masses of Svalbard cover an area of ca 36 600 km2 and more than 60% of the glaciated areas are glaciers which terminate in the sea at calving ice-cliffs. Recent data on the geometry of glacier tongues, their flow velocities and front position changes have been extracted from ASTER images acquired from 2000-2006 using automated methods of satellite image analysis. Analyses have shown that 163 Svalbard glaciers are of tidewater type (having contact with the ocean) and the total length of their calving ice-cliffs is 860 km . When compared with the previous inventory, 14 glaciers retreated from the ocean to the land over a 30-40 year period. Eleven formerly land-based glaciers now terminate in the sea. A new method of assessing the dynamic state of glaciers, based on patterns of frontal crevassing, has been developed. Tidewater glacier termini are divided into four groups on the basis of differences in crevasse patterns and flow velocity: (1) very slow or stagnant glaciers, (2) slow-flowing glaciers, (3) fast-flowing glaciers, (4) surging glaciers (in the active phase) and fast ice streams. This classification has enabled us to estimate total calving flux from Svalbard glaciers with an accuracy appreciably higher than that of previous attempts. Mass loss due to calving from the whole archipelago (excluding Kvitřya) is estimated to be 5.0-8.4 km3 yr-1 (water equivalent - w.e.), with a mean value 6.75 ± 1.7 km3 yr-1 (w.e.). Thus, ablation due to calving contributes as much as 17-25% (with a mean value 21%) to the overall mass loss from Svalbard glaciers. By implication, the contribution of Svalbard iceberg flux to sea-level rise amounts to ca 0.02 mm yr-1. Also calving flux in the Arctic has been considered and the highest annual specific mass balance attributable to iceberg calving has been found for Svalbard.
In summer 1998 detailed measurements of ablation were carried out on the Waldemar Glacier in order to determine its spatial and time variation. Five-days' average ablation was equal to 14.7 cm water equivalent (w.e.), with maximum total ablation of 160-180 cm w.e. at 200 m a.s.l., and the lowest ablation of 106 cm w.e. at 350 m a.s.l. Total ablation for the whole glacier was estimated at 120.5 cm w.e. Simplified scheme of changes of summer ablation with altitude was exampled by this glacier. Relation between discharge from individual fragments of the Waldemar Glacier and their ablation was examined. Discharge of the Waldemar River was analysed: from about 4,800,000 m3 of water in the stream, 67% came from surface ablation of the Waldemar Glacier.
One of the most significant global climatic events in the Cenozoic was the transition from greenhouse to icehouse conditions in Antarctica. Tectonic evolution of the region and gradual cooling at the end of Eocene led to the first appearance of ice sheets at the Eocene/Oligocene boundary (ca. 34 Ma). Here we report geological record of mountain glaciers that preceded major ice sheet formation in Antarctica. A terrestrial, valley-type tillite up to 65 metres thick was revealed between two basaltic lava sequences in the Eocene– Oligocene Point Thomas Formation at Hervé Cove – Breccia Crag in Admiralty Bay, King George Island, South Shetland Islands. K-Ar dating of the lavas suggests the age of the glaciation at 45–41 Ma (Middle Eocene). It is the oldest Cenozoic record of alpine glaciers in West Antarctica, providing insight into the onset of glaciation of the Antarctic Peninsula and South Shetland Islands.
Marine rock-accumulative terraces at 2-230 m a.s.l. in the southern Sörkapp Land are typical for glacioisostaticly uplifted areas. The Holocene terraces reach up to 19 m a.s.l. An outstanding coastal ridge at 9-10 m a.s.l. was radiocarbon-dated at 6580±160 years B.P. No marine transgression during the Holocene on higher and older terraces was noted, what is also confirmed by well preserved raised storm ridges. Any of glacial advances during the Holocene were more extensive than the one of the Little Ice Age. However the Pleistocene glaciations were more extensive. Among glacial landforms in the area there are: ice-cored frontal and lateral moraines up to 70 m high, plains of ground, ablation and fluted moraines, complexes of glaciofluvial fans. The glaciers retreated 0.3-2 km since 1936 i.e. ca 10 m a year on the average. There are large consequent structural landslides on eastern slopes of Keilhaufjellet.
Reduced ice thickness made the glaciers of the northeastern Sörkapp Land occupy considerably smaller area in 1971 than in 1961. Glacial retreat was however more limited in this area than in a remaining part of the Sörkapp Land. Melting of firn intensified processes on mountain slopes.
Diatom assemblages from small pools and creeks on the Ecology Glacier
forefield have been investigated. It is the first study in the Admiralty Bay region after
the thorough taxonomic revision of the non-marine Antarctic diatom flora. A total of
122 diatom taxa, belonging to 35 genera were identified. More than 55% of all observed
species have a restricted Antarctic distribution. Another 15% have a marine origin.
Nitzschia gracilis Hantzsch, N. homburgiensis Lange-Bertalot and Planothidium rostrolanceolatum
Van de Vijver et al. dominated the flora. Based on a DCA analysis,
samples were subdivided in three groups reflecting ecological differences. Several samples
(group 1) showed a mixed freshwater/marine diatom composition and are typical for
coastal pools. Two other groups were separated based on the amount of limnoterrestrial
taxa indicating the temporary character of some of the pools.
The Antarctic Peninsula region has experienced a recent cooling for about 15 years since the beginning of the 21st century. In Livingston Island, this cooling has been of 0.8°C over the 12-yr period 2004–2016, and of 1.0°C for the summer average temperatures over the same period. In this paper, we analyse whether this observed cooling has implied a significant change in the density of the snowpack covering Hurd and Johnsons glaciers, and whether such a density change has had, by itself, a noticeable impact in the calculated surface mass balance. Our results indicate a decrease in the snow density by 22 kg m-3 over the study period. The density changes are shown to be correlated with the summer temperature changes. We show that this observed decrease in density does not have an appreciable effect on the calculated surface mass balance, as the corresponding changes are below the usual error range of the surface mass balance estimates. This relieves us from the need of detailed and time-consuming snow density measurements at every mass-balance campaign.