Results of supervised classification of six Landsat 8 images acquired on: 25 May, 3 June, 22 June, 15 July, 4 August and 20 August 2014, covering glaciers in Hornsund fiord. Method of classification: Maximum Likelihood. The results show variability of snow cover areas in melting period of 2014 for glaciers located in Hornsund fiord and larger than 9 km2 (Körberbreen, Samarinbreen, Chomjakovbreen, Mendelejevbreen, Svalisbreen, Hornbreen, Storbreen, Kvalfangarbreen, Mühlbacherbreen, Paierlbreen and Hansbreen). For more information, please check: https://doi.org/10.3390/w9100804 Overview: Results of Maximum Likelihood classification of Landsat 8 images for analysed glaciers. Red - snow cover, yellow - glacier ice, black - debirs, grey - cloud cover.

The monitoring of the mass balance of the Werenskioldbreen (Wedel Jarlsberg Land, Spitsbergen, Svalbard) in the years 1999-2002 and 2009-2018. It is calculated on the base of 4 to 9 ablation stakes (depend on year). The mass balance is determined by conducting field surveys on floating calendar dates (floating-date system). Data have also been submitted to the World Glacier Monitoring Sevice (WGMS, https://wgms.ch)

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).

1. One UAV movie taken of Paierlbreen in spring 2017 with Phantom 3 Advanced usage. The movie is focused on the front of the glacier and the area around.

Firn extents of Hansbreen and Werenskoildbreen delivered from unsupervised classifications of single, dual and fully-polarimetric SAR data (ALOS-2 PALSAR, RADARSAT-2, Sentinel-1, ERS-2 SAR) between 2011 and 2017. Methods of classification: unsupervised ISO classification, H-a Wishart Classification. Results validated with terrestrial measurements (shallow ice cores drilling, Ground Penetrating Radar measurements). Research supported by the European Space Agency, Third Party Missions grant and Svalbard Science Forum, Arctic Field Grant 2018. For more details, please e-mail to this adress: bbarzycka@us.edu.pl.

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.

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.

Snow depth data series contain records obtained by high frequency GPR on selected glaciers of Hornsund area (S Svalbard) since 2008. Currently the largest collection regards Hansbreen. Data for other glaciers are successively appended. The GPR survey on Hansbreen is regularly carried out approximately along the same tracks. Due to dynamically changing glacier surface topography influencing different survey abilities the some parts of profiles are modified in consecutive seasons. The total distance of Hansbreen profiles are as follows (Fig.1): 63.9 km (2008), 117,5 km (2011), 105,1 km (2013), 103,9 km (2014), 98,5 km (2015), 91,1 km (2016), 101,0 km (2017) and 108,4 km (2018).

Bathymetry at the front of tidewater glaciers derived from different sources. Bathymetry data in Hansbukta and Burgerbukta have been collected by the Norwegian Hydrographic Service using a multi-beam survey during 2007–2008. Later measurements in Hansbukta were collected with single beam profiling at the Hansbreen front in 2015. Data format: grid (6m), UTM 33X. Single echo-sounding data collected during summer 2011, by the University of Silesia.

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).