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.

The mechanism of glacier recession and its climatic controls are complex processes that differ across the Arctic region. Here, we investigate factors influencing front variations of Hansbreen, a glacier terminated in Hornsund fjord (SW Svalbard). We apply remote sensing data to observe glacier front fluctuations between 1992 and 2015 and compare them to atmospheric and oceanographic data, sea water depth at the terminus and surface velocity. Rate of subglacial meltwater discharge approximated by the seasonal positive degree‐day index (PDD) together with sea thermal conditions appear to be the main factors responsible for the fluctuations of the front of Hansbreen, while water depth at the front plays a secondary role. Taking into account ocean and air thermal conditions, the studied period has been divided into warm, cold and moderate years. The glacier retreated considerably throughout a bedrock overdeepening in the very warm period 2012–2014. This recession coincided with a slower ice flow due to intense subglacial runoff and increased submarine melting. The long‐term retreat was interrupted by glacier advances in colder years, regardless of water depth at the front. The slower recession rate was the combined effect of decreased subglacial melting and increased glacier movement associated with lower subglacial runoff. Although the seasonal PDD is a good indicator of the front fluctuations, the duration of the retreat and advance periods are strongly correlated with the sea surface temperature. Expected climate warming and an increase of water temperature in the West Spitsbergen Current will stimulate further recession of Hansbreen in future.

In this study, we assess the accuracy and precision of digital elevation models (DEM) retrieved from aerial photographs taken in 2011 and from Very High Resolution satellite images (WorldView-2 and Pléiades) from the period 2012–2017. Additionally, the accuracy of the freely available Strip product of ArcticDEM was verified. We use the DEMs to characterize geometry changes over Hansbreen and Hornbreen, two tidewater glaciers in southern Spitsbergen, Svalbard. The satellite-based DEMs from WorldView-2 and Pléiades stereo pairs were processed using the Rational Function Model (RFM) without and with one ground control point. The elevation quality of the DEMs over glacierized areas was validated with in situ data: static differential GPS survey of mass balance stakes and GPS kinematic data acquired during ground penetrating radar survey. Results demonstrate the usefulness of the analyzed sources of DEMs for estimation of the total geodetic mass balance of the Svalbard glaciers. DEM accuracy is sufficient to investigate glacier surface elevation changes above 1 m. Strips from the ArcticDEM are generally precise, but some of them showed gross errors and need to be handled with caution. The surface of Hansbreen and Hornbreen has been lowering in recent years. The average annual elevation changes for Hansbreen were more negative in the period 2015–2017 (−2.4 m a⁻¹) than in the period 2011–2015 (−1.7 m a⁻¹). The average annual elevation changes over the studied area of Hornbreen for the period 2012–2017 amounted to −1.6 m a⁻¹. The geodetic mass balance for Hansbreen was more negative than the climatic mass balance estimated using the mass budget method, probably due to underestimation of the ice discharge. From 2011 to 2017, Hansbreen lost on average over 1% of its volume each year. Such a high rate of relative loss illustrates how fast these glaciers are responding to climate change.

Rapid Arctic warming results in increased winter rain frequencies, which may impact glacial systems. In this paper, we discuss climatology and precipitation form trends, followed by examining the influence of winter rainfall (Oct–May) on both the mass balance and dynamics of Hansbreen (Svalbard). We used data from the Hornsund meteorological station (01003 WMO), in addition to the original meteorological and glaciological data from three measurement points on Hansbreen. Precipitation phases were identified based on records of weather phenomena and used—along with information on lapse rate—to estimate the occurrence and altitudinal extent of winter rainfall over the glacier. We found an increase in the frequency of winter rain in Hornsund, and that these events impact both glacier mass balance and glacier dynamics. However, the latter varied depending on the degree of snow cover and drainage systems development. In early winter, given the initial, thin snow cover and an inefficient drainage system, rainfall increased glacier velocity. Full-season winter rainfall on well-developed snow was effectively stored in the glacier, contributing on average to 9% of the winter accumulation.