Recent transformations in the high‐arctic glacier landsystem, ragnarbreen, svalbard

Abstract

ABSTRACT. Ragnarbreen is a small glacier located in the central part of Spitsbergen Island (Svalbard archipelago) and fed by the larger ice mass of Mittag-Lefflerbreen. Glacier recession and landform development in the foreland of Ragnarbreen are quantified using time-series orthophotos and digital elevation models, which were generated based on aerial photographs from 1961 (black and white frame camera), 1990 (false infrared frame camera) and 2009 (colour digital camera), obtained from the Norsk Polar Institute.Receding from its maximum Little Ice Age extent, attained in the period 1900/1920-2013, the glacier margin retreated by 1658 m while the extent of the area of ice decreased by 26%. The glacier snout lost 135 million m 3 of ice during the period 1961-2009, whereas landform changes (mainly due to dead-ice melting and debris flow activity) were more than twenty five times lower, with the less than 5 million m 3 of sediment and dead ice volume loss. In terms of landscape alteration between 1961 and 2009, the most important was the creation of a terminoglacial lake, which acted as a sedimentary trap and at the same time probably accelerated glacier retreat. The second most active component was the lateral moraines whose transformations were divided into four phases, with various magnitudes of debris flow and backwasting activity that changed with time. The end moraine complex was the most stable component, affected mainly by dead-ice downwasting and to a lesser extent by sporadic debris flows.

Glacial geomorphology of the terrestrial margins of the tidewater glacier, Nordenskiöldbreen, Svalbard

“…The amount of dead-ice is limited (compared to the southern side), hence transformation of landforms due to dead-ice melting is spatially restricted to very small areas located near the northern lateral glacier margin. The overall volume of sediment on the north foreland is very small in comparison not just to the southern side but also to other glaciers in the surrounding area (Evans et al, 2012;Ewertowski, 2014;Ewertowski, Kasprzak, Szuman, & Tomczyk, 2012;Gonera & Kasprzak, 1989). The cause of the limited debris volume and relatively small number and size of constructional landforms on the north foreland likely relates to the fact that this side of the glacier has been influenced by a wide, single flow unit, which drains the Lomonosovfonna plateau, so the possibility of incorporating supraglacial debris was very limited and restricted only to the fringes of the flow units.…”

“…Nordenskiöldbreen has been the subject of a number of glaciological (Den Ouden et al, 2010;Hagen, Eiken, Kohler, & Melvold, 2005;Rachlewicz et al, 2007;Van Pelt et al, 2012, 2014 and geomorphological (Boulton, 1970(Boulton, , 1976Kłysz, 1988;Kłysz, Lindner, Marks, & Wysokiński, 1989;Slater, 1925;Stacke, Mida, Lehejček, Tóthová, & Nývlt, 2013;Strzelecki, 2011) studies, including some geomorphological mapping (Karczewski et al, 1990;Kłysz et al, 1989) (Baeten, Forwick, Vogt, & Vorren, 2010;Plassen, Vorren, & Forwick, 2004;Szczuciński, Zajączkowski, & Scholten, 2009). However, most of the previous work concentrated on the northern margin, and so far no coherent map of glacial geomorphology has been produced for both terrestrial parts of the foreland and hence no comparison has been made between the landform signatures of these two clearly contrasting parts of the snout.…”

Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard

“…Previous works on glaciers and glacial landforms in the study area concern both geomorphology (e.g. Kłysz, 1985;Gonera and Kasprzak, 1989;Karczewski, 1989;Stankowski et al, 1989;Karczewski et al, 1990;Karczewski and Kłysz, 1994;Gibas et al, 2005;Rachlewicz and Szczuciński, 2008;Rachlewicz, 2009Rachlewicz, , 2010Szuman and Kasprzak, 2010;Hanáček et al, 2011;Evans et al, 2012;Ewertowski et al, 2012;Ewertowski, 2014) and glaciology (e.g. Rachlewicz, 2009;Małecki, 2013Małecki, , 2014Małecki et al, 2013).…”

Ice-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: A case study from a polythermal glacier in Svalbard

“…Conversely, where debris cover is sufficiently thick, it has been reported that ice-cored moraine may stabilise, undergoing limited or negligible rates of transformation (Ewertowski, 2014;Ewertowski and Tomczyk, 2015).…”