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)

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).

The database contains irregular meteorological data collected from the Hans Glacier (Hansbreen) in the years 2007-2017 as part of the polar expeditions of the University of Silesia in Spitsbergen / Svalbard. Data from three automatic weather stations. Measured elements: air temperature, air humidity, wind direction, wind speed, elements of radiation balance, others.

Dataset contains snowpack density derived from shallow snow cores. Fieldwork has been done during peak of accumulation on several glaciers in the region of Hornsund, Svalbard: Amundsenisen (2013) Werenskioldbreen (2013, 2015) Nannbreen (2013) Flatbreen (2013, 2018) Storbreen (2013, 2018) Results might be valuable i.a. for mass-balance estimations or GPR survey validation. Acknowledgements: Research Council of Norway, Arctic Field Grant 2013: Spatial distribution of snow cover and drainage systems on the glaciers on Wedel Jarlsberg Land (RiS ID: 6158); the National Science Centre PRELUDIUM 4: Role of meltwater from snow cover for supplying drainage systems of the Spitsbergen glaciers (2012/07/N/ST10/03784); Citation: LASKA M.,GRABIEC M.,IGNATIUK D.,BUDZIK T.,2017. Snow deposition patterns on southern Spitsbergen glaciers, Svalbard, in relation to recent meteorological conditions and local topography. Geografiska Annaler, Series A: Physical Geography, 99(3): 262–287. doi:10.1080/04353676.2017.1327321

Dataset contains evolution of the snow temperature within seasonal snowpack on Hansbreen. Fieldwork has been performed with several thermistors located at different levels (from snow surface to the bottom, on glacier ice) from April to July 2010 (during period of early and intensive surface melting). Study has been repeated in 2015, at the same location. Acknowledgements: Research Council of Norway, Arctic Field Grant 2013: Spatial distribution of snow cover and drainage systems on the glaciers on Wedel Jarlsberg Land (RiS ID: 6158); the National Science Centre PRELUDIUM 4: Role of meltwater from snow cover for supplying drainage systems of the Spitsbergen glaciers (2012/07/N/ST10/03784) References: Laska M., Luks B., Budzik T., 2016. Influence of snowpack internal structure on snow metamorphism and melting intensity on Hansbreen, Svalbard. Polish Polar Research, 37(2): 193–218. doi:10.1515/popore-2016-0012

Thermal structure of selected S Spitsbergen glaciers was derived from ground based radio-echo sounding (RES). The division between cold and temperate ice layers is based on indirect interpretation of GPR (ground penetrating radar) image. Cold ice layer is virtually “transparent” for radio waves, while temperate ice layer is characterised by numerous diffractions on water inclusions. The database contains results from 479.7 km of RES profiles acquired in 2007-2014 on 12 glaciers in Wedel Jarlsberg Land and Torell Land (S Spitsbergen) including: Amundsenisen, Austre Torellbreen, Vestre Torellbreen, Hansbreen, Storbreen, Hornbreen, Hambergbreen, Recherchebreen, Scottbreen, Renardbreen, Werenskioldbreen and Ariebreen. Basic characteristics of investigated glaciers and its thermal structure is provided in table 1 (supplementary information). The surveys used GPR antennas in range 25-200 MHz, selected according to expected ice depth. Thanks to that on 87% of the profiles ice/bed interface has been identified. The radar system was pulled behind the snowmobile moving with velocity c. 20 km h-1. Applying trace interval 0.2-1.0 s, trace-to-trace distance was in range 1-5m. Trace positions were acquired by GNSS receivers working in navigation or differential mode with respective accuracy 3.0 m and 0.1m. RES data were processed applying standard filtering procedure (DC-offset, time-zero adjustment, 2-D filter, amplitude correction and bandpass filtering). Time-to-depth conversion used average radio wave velocity (RWV) for glacier ice 16.4 cm ns-1, 16.7 and 16.1 for cold and temperate ice respectively, based on CMP survey. More precise description of data collection, processing and quality is provided by Grabiec (2017). In S Spitsbergen polythermal glaciers are predominant. 57.8% of surveyed profiles consist of both: temperate and cold ice layers; 22.7% profiles is entirely temperate while 6.6% contains cold ice only (remaining profiles have undefined thermal structure). Studied glaciers represent broad spectrum of polythermal structure with cold-to-temperate ice ratio from 99:1% (Ariebreen) to 2:98% (accumulation zone of Vestre Torellbreen). 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 • NCBiR/PolarCLIMATE-2009/2-1/2010 SvalGlac Sensitivity of Svalbard glaciers to climate change • Pol-Nor/198675/17/2013 AWAKE-2 Arctic climate system study of ocean, sea ice and glaciers interactions in Svalbard area • 03/KNOW2/2014 KNOW Leading National Research Centre Reference: Grabiec M. 2017: Stan i współczesne zmiany systemów lodowcowych południowego Spitsbergenu w świetle badań metodami radarowymi. Wydawnictwo Uniwersytetu Śląskiego, 328 s.

• Data set of daily suspended sediment transport from the Breelva (glacier river), which drains the Werenskioldbreen (Southwestern Spitsbergen), for the period 2007–2012 (Appendix I). • Period of sampling, range of the suspended sediment concentration (SSC), total suspended sediment load (SSL), and the rate of mechanical denudation and also total annual runoff (Qtotal) from Werenskioldbreen catchment for the studied seasons (1972, 1986 and 2007–2012) (Appendix II). Detailed information can be found in: Pulina, M. Preliminary studies on denudation in SW Spitsbergen. Bull. Acad. Pol. Sci. Terre 1974, 22, 83–99. Krawczyk, W., Opołka-Gądek, J. Suspended sediment concentration in the Werenskiold Glacier drainage basin in 1986. In XXI Polar Symposium; Zalewski, M.S., Ed.; Institute of Geophysics Polish Academy of Sciences: Warszawa, Poland, 1994; pp. 215–224, ISBN 8385173374. Łepkowska E., Stachnik Ł., 2018. Which drivers control the suspended sediment flux in a High Arctic glacierized basin (Werenskioldbreen, Spitsbergen)? Water, 10, 1408. doi: https://doi.org/10.3390/w10101408

1. Dataset of UAV vertical aerial photos of front and ice melange in the north part of Tunabreen, obtained in spring 2017. Area covered: ~1600x~800m. Used UAV: Phantom 3 Advanced, flight height: 100m. Data obtained during fieldwork supported by Svalbard Science Forum, Arctic Field Grant 2017 with cooperation with University of Maine (USA) and the University Centre in Svalbard (Norway).

Since 2010, continuous monitoring of the front zone of the Hansa Glacier with the use of Canon Eos 1000D photo cameras has been carried out (timelapse). Pictures in different periods of time were taken by 3 different cameras. Two cameras (106 and 107) were located on the Fugleberget slope and one (601) on the Baranowskiodden. The periods for which data are available and the interval of taking pictures are shown in Appendix 1.