Glacier velocities are derived from the displacements of four stakes (Z, R, T, U) installed close to the front of three glaciers in Hornsund. Measurements of stakes position were conducted in 2013-2015, with precise dGPS receiver (Leica 1230, accuracy ±5cm) and single-frequency GPS receiver (Garmin, accuracy ±5m). Detailed description of the source data and accuracy can be found in: Błaszczyk M., Ignatiuk D., Uszczyk A., Cielecka-Nowak K., Grabiec M., Jania J., Moskalik M., Walczowski W., 2019. Freshwater input to the Arctic fjord Hornsund (Svalbard). Polar Research, 38. https://doi.org/10.33265/polar.v38.3506

Radar satellite (SAR) images for Hornsund: ERS-1, ERS-2, ENVISAT, ALOS Palsar, TerraSAR-X, TandemX-1, acquired between 1992 and 2014. 210 archival SAR data were provided at the SLC level, so that both radiometric and geometric corrections were applied using the same methods, and with the same digital elevation model (2008 DEM SPOT developed by the IPY-SPIRIT Project; Korona et al., 2009). The SAR data were processed in BEAM (http://www.brockmann-consult.de/cms/web/beam).

Subglacial topography was derived from radio-echo sounding (RES) survey conducted in spring 2008 by the University of Silesia research team (M. Grabiec and J. Jania) in cooperation with the Institute of Geophysics Polish Academy of Sciences (D. Puczko) and the Maria Curie-Sklodowska University (G.Gajek). The profiles were acquired by the radar system equipped with 25 MHz unshielded antenna pulled behind snowmobile. Traces were recorded every 0.5 s, that translates into 1.5-2.0 trace-to-trace distance depending on the vehicle’s velocity. Traces were positioned by GNSS receiver working in differential mode with 3D accuracy ± 1m. In total over 100 km of RES profiles were acquired on Hansbreen, 66 km on Werenskioldbreen and 43 km on Renardbreen. RES data were processed using standard procedure including: DC-offset, time-zero adjustment, 2-D filter, amplitude correction, bandpass filtering and migration. Time-to-depth conversion applied average radio-wave velocity in glacier ice 16.4 cm ns-1 calculated based on CMP analysis performed on Hansbreen in the same season as the GPR profiling. The ice/bed interface was picked up semi-automatically with RMSE 5.3 ns (0.43 m) (Grabiec, 2017). Then the bedrock elevation data were interpolated over studied glaciers taking into account elevation of nonglaciated surroundings (Grabiec 2017) and bathymetry at the front of tidewater Hansbreen (Grabiec et al. 2012). Finally produced 100 m resolution DEMs are in UTM 33X WGS84 reference system. DEM of 300 m resolution is freely available. For 100 m resolution DEM please contact: mariusz.grabiec@us.edu.pl. The data were collected and processed under following projects: • IPY/269/2006 GLACIODYN The dynamic response of Arctic glaciers to global warming • UE FP7-ENV-2008-1 ice2sea Estimating the future contribution of continental ice to sea-level rise • PNRF-22-AI-1/07 AWAKE Arctic Climate and Environment of the Nordic Seas and the Svalbard – Greenland Area • 03/KNOW2/2014 KNOW Leading National Research Centre Reference: Grabiec M., Jania J., Puczko D., Kolondra L., and Budzik T., 2012: Surface and bed morphology of Hansbreen, a tidewater glacier in Spitsbergen. Polish Polar Research 38(2): 111-138. Grabiec M. 2017: Stan i współczesne zmiany systemów lodowcowych południowego Spitsbergenu w świetle badań metodami radarowymi. Wydawnictwo Uniwersytetu Śląskiego, 328 s. Decaux, L., Grabiec, M., Ignatiuk, D., and Jania, J. 2018: Role of discrete recharge from the supraglacial drainage system for modelling of subglacial conduits pattern of Svalbard polythermal glaciers, The Cryosphere Discuss., https://doi.org/10.5194/tc-2017-219, in review.

1. Dataset of UAV vertical aerial photos of Calypsobyen obtained from height of: 100m (58 photos), 60m (45 photos) and 30m (59 photos). Used UAV: Phantom 3 Advanced, date of acqusition: 16 Aug 2016. 2. Dataset of UAV vertical aerial photos of Paierlbreen east morain/dead ice obtained from height of 50m (152 photos). Area covered: ~250x~130m (with gaps).Used UAV: Phantom 3 Advanced, date of acqusition: 22 Aug 2016. 3. Dataset of UAV vertical aerial photos of Storbreen, close to Komsa (52 photos). Area covered: ~350x~230m. Used UAV: Phantom 3 Advanced, date of acqusition: 21 Aug 2016. 4. Dataset of UAV vertical aerial photos of Werenskoildbreen's south moraine (300 photos). Area covered: ~200x~350m and ~250x~250m. Used UAV: Phantom 3 Advanced, date of acqusition: 7 Sep 2016.

High resolution orthophoto images from Geoeye, WorldView-2 and Pléaides processed in OrthoEngine module of PCI Geomatica. Data format: grid, UTM 33X / EGM 2008. Spatial resolution: 0.5 m (panchromatic and pansharpened) and 2 m (multispectral).

Glaciers facies extents of Vestfonna delivered from unsupervised classifications of SAR data (fully-polarimetric ALOS PALSAR, single polarimetric ERS-2 SAR) for 2009 year. Date of SAR images acquisitions: 4, 7, 20, 23, 26 May 2009 (VV Single Look Complex ERS-2 SAR), 22 May 2009 (ALOS PALSAR Single Look Complex 1.1, quad polarimetry). Method of classification: K-means classification, H-a Wishart Classification. Results validated with Ground Penetrating Radar data. For more information, please check: https://doi.org/10.1016/j.rse.2018.11.020 Overwiew of results of different classification methods with comparison to GPR data. Top panel: Pauli decomposition, middle panel: H-a Wishart classification, bottom panel: k-means classification. For more information, please check: https://doi.org/10.1016/j.rse.2018.11.020 (Figure 7).

Meteorological data from Flat Glacier (Flatbreen) - air temperature.

Digital elevation model (DEM) with high spatial resolution derived from aerial images captured in 2020 over Hornsund, Svalbard by Dornier aircraft. The spatial resolution of the orthomosaic is 0.169 m. Aerial images for the area were provided by the SIOS through a dedicated call of proposals (https://sios-svalbard.org/AirborneRS). The dataset is the supplement to the paper: Błaszczyk, M.; Laska, M.; Sivertsen, A.; Jawak, S.D. Combined Use of Aerial Photogrammetry and Terrestrial Laser Scanning for Detecting Geomorphological Changes in Hornsund, Svalbard. Remote Sens. 2022, 14, 601. https://doi.org/10.3390/rs14030601

The internal structure of glaciers evolves primarily due to their thermal state, which is influenced by ongoing climate change. Radio-echo sounding is a technique that indirectly identifies water-saturated temperate ice (W-STI) and water-free ice (W-FI) within glaciers. A novel automatic image processing method based on local binarization has been developed to improve the accuracy and efficiency of identifying these layers. Applied to the Arctic glacier Hansbreen from 2007 to 2021, this technique revealed that the glacier’s internal structure evolved from a two-layer system to a nearly homogeneous structure composed mainly of temperate ice (Kachniarz et al. 2025). The dataset contains raw GPR data from 2007 - 2021 taken in the Hansbreen ablation zone used to identify the glacier's internal structure. The profiles are divided into two sections: upper and lower areas. The upper area includes GPR profiles intended to replicate the 2003 GPR profile. The lower area consists of profiles shifted down the glacier, corresponding to the glacier’s movement since 2003. The profile lengths range from 0.7 km to 1.7 km, with the 2016 lower and 2021 upper areas, respectively. In the first season (2007), the GPR profiles were situated at altitudes between 188 and 216 meters above sea level, running transversely to the glacier’s movement. The glacier’s internal structure was examined using GPR system with unshielded 25 MHz, Rough Terrain Antenna (RTA) 30 MHz, and RTA 50 MHz antennas. Image processing Python script based on local binarization and processed image examples have been included in the dataset. See details in Kachniarz et al. 2025. The field data collection and/or processing received grant aid from: Svalbard Integrated Arctic Earth Observing System (SIOS) (SnowInOpt: SIOS Infrastructure Optimisation of the Cal/Val process for the snow research), European Commission Horizon Europe HORIZON-CL5-2024-D1-01-02 (LIQUIDICE: LinkIng and QUantifying the Impacts of climate change on inlanD ICE, snow cover, and permafrost on water resources and society in vulnerable regions) 101184962, the National Centre for Research and Development within the Polish-Norwegian Research Cooperation Programme (AWAKE2 project Pol Nor/198675/17/2013), Polish-Norwegian funding (AWAKE project PNRF-22-AI-1/07), Polish Ministry of Science and Higher Education (GLACIODYN No. IPY/269/2006), PolishNational Centre for Research and Development (SvalGlac project No. NCBiR/PolarCLIMATE-2009/2-2/2010), European Union 7th Framework Programme (ice2sea programme, grant no. 226375. Glaciological data were processed under assessment of the University of Silesia data repository within project Integrated Arctic Observing System (INTAROS, European Union’s Horizon 2020 Research and Innovation Programme—grant No. 727890). The work was supported by the Centre for Polar Studies (the Leading National Research Centre in Earth Sciences for 2014–2018) funding, No. 03/KNOW2/2014. Reference: Kachniarz K., Grabiec M., Wróbel K., Ignatiuk D. 2025: Glacier internal structure revealed by automatic image processing-powered classification of radar images. Applied Geomatics (in review)

Hansbreen velocity is measured with a Global Navigation Satellite Systems (GNSS) receiver that sampled location every 3 hours at stake 4MONIT located approximately 3.5 km upstream of the glacier terminus (N77°02’ E15°28’). Monitoring of the glacier is conducted by Institute of Geophysics Polish Academy of Science. We calculate the daily speed based on each midnight positions (with a horizontal accuracy of ±4 cm).