Surge dynamics in the Nathorstbreen glacier system, Svalbard

Abstract

Abstract. Nathorstbreen glacier system (NGS) recently experienced the largest surge in Svalbard since 1936, and this was examined using spatial and temporal observations from DEM differencing, time series of surface velocities from satellite synthetic aperture radar (SAR) and other sources. The upper basins with maximum accumulation during quiescence corresponded to regions of initial lowering. Initial speed-up exceeded quiescent velocities by a factor of several tens. This suggests that polythermal glacier surges are initiated in the temperate area before mass is displaced downglacier. Subsequent downglacier mass displacement coincided with areas where glacier velocity increased by a factor of 100-200 times (stage 2). After more than 5 years, the joint NGS terminus advanced abruptly into the fjord during winter, increasing velocities even more. The advance was followed by up-glacier propagation of crevasses, indicating the middle and subsequently the upper part of the glaciers reacting to the mass displacement. NGS advanced ∼15 km, while another ∼3 km length was lost due to calving. Surface lowering of ∼50 m was observed in some up-glacier areas, and in 5 years the total glacier area increased by 20 %. Maximum measured flow rates were at least 25 m d −1 , 2500 times quiescent velocity, while average velocities were about 10 m d −1 . The surges of Zawadzkibreen cycle with ca. 70-year periods.

Circum-Arctic Changes in the Flow of Glaciers and Ice Caps from Satellite SAR Data between the 1990s and 2017

“…The comparison of Figure 9a,b also nicely shows the end of the surge of the Nathorstbreen glacier system, which started in 2009 with a frontal advance of about 15 km [17]. In order to further characterize the spatio-temporal dynamic pattern of this glacier system we compare in Figure 11a For many other glaciers over the Svalbard Archipelgo a steady increase of frontal velocities along with a retreat of frontal positions is observed.…”

“…This region was also investigated by [8] with a focus on mass budgets (both surface and calving) for the 1991-2015 period. Similarly, Melkonian, A. et al [14] investigated velocities and elevation changes for Novaya Zemlya (Russian Arctic) and numerous studies have analysed the changes in Svalbard (e.g., [5,15,16]) with a special focus on surge-type (e.g., [17][18][19]) or continuously fast-flowing (e.g., [20]) glaciers. However, there are no comprehensive recent studies on flow velocities for GIC on Franz Josef Land and Severnaja Zemlya, only older ones [21,22] or short communications on rapid glaciers changes [23].…”

Surface speed and frontal ablation of Kronebreen and Kongsbreen, NW Svalbard, from SAR offset tracking

“…The overall ice flux to the ocean from all 163 Svalbard glaciers was estimated to be 6.75 ± 1.7 Gt a −1 (Blaszczyk et al, 2009), and Kronebreen and Kongsbreen are major contributors with shares of 4.0 and 2.5 %, respectively. Nevertheless, this number does not include mass loss related to major surges, such as of Basin-3 on Austfonna since 2012 (4.2 ± 1.6 Gt a −1 , Dunse et al, 2015) and between 2009 and 2013 of Nathorstbreen (Sund et al, 2014).…”

An Inter-Comparison of Techniques for Determining Velocities of Maritime Arctic Glaciers, Svalbard, Using Radarsat-2 Wide Fine Mode Data

“…In 2009, Dobrowolskibreen started to surge, and in 2010 the whole Nathorstbreen system consisting of Nathorstbreen (N), Dobrowolskibreen (D), Polakbreen (P) and Zawatzkibreen (Z) followed [20]. Sund et al [20] found maximum velocities of 25 m·d −1 during the initiation of the Nathorstbreen glacier system surge. Three years later, the glacier still flows at an accelerated rate with a maximum velocity of about 3 m·d −1 .…”

“…Glacier surface velocity is known for many glaciers on Svalbard (e.g., [12][13][14][15][16][17][18][19][20][21]), but none of these studies provide an overview of velocities across the entire archipelago. The first goal of this study is therefore to provide the first complete surface velocity map for all glaciers on Svalbard.…”