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.

• Discharge measurements were conducted from May/June/July to September/October in the years 2007–2012. Direct observation periods were 62, 51, 61, 40, 121, and 35 days in the consecutive years. The data set was obtained from CTD-DIVER DI 261 or Mini-Diver (Van Essen Instruments, Delft, The Netherlands) logger with barometric compensation by BaroDiver (Schlumberger, Houston, TX, USA) with 10-min intervals and flow velocities were measured with a SEBA F1 current meter (SEBA Hydrometrie GmbH, Kaufbeuren, Germany). Mean daily discharge and total runoff in the hydrologically active season was calculated on the basis of the 24h running average of the water level and a rating curve (Appendix 1). More details have been reported by Majchrowska E., Ignatiuk D., Jania J., Marszałek H., Wąsik M., 2015: Seasonal and interannual variability in runoff from the Werenskioldbreen catchment, Spitsbergen. Polish Polar Research vol. 36, no. 3, pp. 197–224. doi: 10.1515/popore−2015−0014 • Hydrological data for Werenskioldbreen - archive of the University of Silesia. The base contain mean daily discharge in the years: 1972, 1973, 1974, 1979, 1980, 1983, 1985, 1986, 1988, 1998, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2017 (18 hydrologically active seasons) – Appendix 2

The base contain: 1. List (*xls) of terrophotogrammetric photographs taken by Poles na Spitsbergen from 1934 till 2016: 2. Skaning above photographs with resolution of 2400 dpi, file format *.tif and *.jpg (400 dpi). All photographs were taken by means of instrument type Phototheodolite Zeiss 19/1318 on glass plates. Authors of photographs: Antoni Rogala-Zawadzki, Cezary Lipert, Stanisław Rudowski, Leszek Kolondra, Jacek Jania, Jerzy Wach, Krzysztof Migała, Janusz Karkoszka, Małgorzata Błaszczyk and other unknown members of Polish Expeditions organized by Institute of Geophysic Polish Academy of Science in Station HORNSUND. Fot better identification of all photographs was prepared presentations (in *.pptx and *.pdf formats), where photographs there are arranged in classic form used for terrophotogrammetric stereoscopic photographs: A, AL, AR, B, BL, BR (the meaning of a letter: A - right photogrammetric station and photograph taken in normal case [90°]; B - left photogrammetric station and photograph taken in normal case [90°]; AL - photograph taken from right station in left direction; AR - photograph taken from right station in right direction; BL - photograph taken from left station in left direction; BR - photograph taken from left station in right direction). Other photographs (e.g. panoramic) has additional informations. Boths kind of presentation are prepared in chronological and tematical (for objects) order.

Hornsund area extracted from different archive data. Detailed description of the source data and accuracy data for glaciers from hydrological basin of Hornsund can be found in: Błaszczyk M., Jania J.A., Kolondra L., 2013: Fluctuations of tidewater glaciers in Hornsund Fiord (Southern Svalbard) since the beginning of the 20th century. Polish Polar Research, 34( 4): 327-352. http://journals.pan.pl/dlibra/publication/114504/edition/99557/content

• 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

The positions of the glacier termini in Hornsund are derived with very high frequency in the period 1991–2018. Over 230 multispectral and Synthetic Aperture Radar (SAR) data were used: LANDSAT 5, LANDSAT 7, LANDSAT 8, Terra ASTER, Alos AVNIR, SPOT 5, ERS-1, ERS-2, ENVISAT, Alos PALSAR, TerraSAR-X, TanDEM-X, and Sentinel-1. SAR data were used to detect any variability in the glacier front during the polar night. The satellite data were digitized manually to obtain the ice cliff position. Multispectral images were orthorectified and geocoded in PCI Geomatica and ArcGIS software. SAR data were usually provided at the SLC level, so that both radiometric and geometric corrections could be 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). Sentinel data downloaded from the Sentinel’s Data Hub were already processed. Data not published.

Inventory of tidewater and landbased glaciers delineated from archival satellite images (ASTER, Landsat) for Southern Spitsbergen. Tidewater glaciers are delineated based on satellite data from 2010. Landbased glacier are extracted from different satellite data (2005-2010). Shapefiles have basic information in the attribute table (name, ID, area, type of glaciers). Detailed description of the source data and accuracy data for glaciers from hydrological basin of Hornsund can be found in: Błaszczyk M., Jania J.A., Kolondra L., 2013: Fluctuations of tidewater glaciers in Hornsund Fiord (Southern Svalbard) since the beginning of the 20th century. Polish Polar Research, 34( 4): 327-352.http://journals.pan.pl/dlibra/publication/114504/edition/99557/content

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

Dataset contains location of glacial shafts (moulins) on two polythermal glaciers: Werenskioldbreen and Hansbreen. Fieldwork has been done with GPS device at the end of ablation season in 2015. 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)

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