• 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

• 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

Ice condition directly at the Hansbreen front is obtained from visual interpretation of oblique pictures taken at 3 h intervals by Canon EOS 1000D time-lapse photography (Figure 1) for the period 2010–2015 (https://ppdb.us.edu.pl/geonetwork/srv/pol/catalog.search;jsessionid=muhaqbum8pz21xknjo0crhodn?node=srv#/metadata/cf6a17fd-ec3a-4ff6-8232-67a0dc5957d4) The database is the supplement to the paper: Małgorzata Błaszczyk, Jacek A. Jania, Michał Ciepły, Mariusz Grabiec, Dariusz Ignatiuk, Leszek Kolondra, Aleksandra Kruss, Bartłomiej Luks, Mateusz Moskalik, Tadeusz Pastusiak, Agnieszka Strzelewicz, Waldemar Walczowski, Tomasz Wawrzyniak. “Factors controlling terminus position of Hansbreen, a tidewater glacier in Svalbard”, Journal of Geophysical Research - Earth Surface, https://doi.org/10.1029/2020JF005763.

Average terminus height above sea level for the period 1992–1996, 2000 and 2010 was acquired with an accuracy of ±1.5 m, using terrestrial photogrammetry. The glacier terminus height in September 2009 and 2015 was measured using precise laser scanning with an accuracy of ±0.5 m. The height data obtained using photogrammetry and a laser scanner are averaged along the ice face. The database is the supplement to the paper: Małgorzata Błaszczyk, Jacek A. Jania, Michał Ciepły, Mariusz Grabiec, Dariusz Ignatiuk, Leszek Kolondra, Aleksandra Kruss, Bartłomiej Luks, Mateusz Moskalik, Tadeusz Pastusiak, Agnieszka Strzelewicz, Waldemar Walczowski, Tomasz Wawrzyniak. “Factors controlling terminus position of Hansbreen, a tidewater glacier in Svalbard”, Journal of Geophysical Research - Earth Surface, https://doi.org/10.1029/2020JF005763.

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.

Ice front position of the tidewater glaciers in Hornsund was examined during the following periods: 1899–1936–1960/1961–1976–1990–2001–2005–2010. For the period 1899–1990, several archival maps of varying accuracy were used, sometimes difficult to assess. For the period 1976–2010 multispectral and radar satellite images were used. Detailed description of the source data and accuracy 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.

The position of the terminus of Hansbreen is derived with very high frequency in the period 1991–2015. Over 160 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. Terra ASTER images were orthorectified with use of 2008 DEM SPOT and geocoded in PCI Geomatica and ArcGIS software. Multispectral, already terrain-corrected images were rectified in ArcGIS software. SAR data were provided at the Single Look Complex level and that both radiometric and geometric corrections were applied using the same methods, and with the same digital elevation model (2008 DEM SPOT). 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. The satellite data were digitized manually to obtain the front position. The database is the supplement to the paper: Małgorzata Błaszczyk, Jacek A. Jania, Michał Ciepły, Mariusz Grabiec, Dariusz Ignatiuk, Leszek Kolondra, Aleksandra Kruss, Bartłomiej Luks, Mateusz Moskalik, Tadeusz Pastusiak, Agnieszka Strzelewicz, Waldemar Walczowski, Tomasz Wawrzyniak. “Factors controlling terminus position of Hansbreen, a tidewater glacier in Svalbard”, Journal of Geophysical Research - Earth Surface, https://doi.org/10.1029/2020JF005763.

The longitudinal profile of the glacier surface is derived from continuous DEM generated from WorldView-2 satellite data (Błaszczyk et al., 2019), while profile of the bed under the glacier is interpolated from ground-penetrating radar data (Grabiec et al., 2012). Grabiec, M., Jania, J. A., Puczko, D., Kolondra, L., & Budzik, T. (2012). Surface and bed morphology of Hansbreen, a tidewater glacier in Spitsbergen. Polish Polar Research, 33(2), 111–138. https://doi.org/10.2478/v10183−012−0010−7 Błaszczyk, M., Ignatiuk, D., Grabiec, M., Kolondra, L., Laska, M., Decaux, L., Jania, J., Berthier, E., Luks, B., Barzycka, B., & Czapla, M. (2019). Quality assessment and glaciological applications of digital elevation models derived from space-borne and aerial images over two tidewater glaciers of southern Spitsbergen. Remote Sensing, 11(9), 1121. https://doi.org/10.3390/rs11091121 The database is the supplement to the paper: Małgorzata Błaszczyk, Jacek A. Jania, Michał Ciepły, Mariusz Grabiec, Dariusz Ignatiuk, Leszek Kolondra, Aleksandra Kruss, Bartłomiej Luks, Mateusz Moskalik, Tadeusz Pastusiak, Agnieszka Strzelewicz, Waldemar Walczowski, Tomasz Wawrzyniak. “Factors controlling terminus position of Hansbreen, a tidewater glacier in Svalbard”, Journal of Geophysical Research - Earth Surface, https://doi.org/10.1029/2020JF005763.

Glaciers facies extents of Langjökull delivered from unsupervised classifications of fully-polarimetric SAR data (ALOS-2 PALSAR, RADARSAT-2) for 2018 year. Date of SAR images acquisitions: 12, 16 Mar 2018 (Fine Quad Pol RADARSAT-2), 17 Mar 2018 (High Sensitive Quad Pol ALOS-2 PALSAR). Method of classification: H-a Wishart Classification. Results validated with terrestrial measurements (shallow ice cores drilling, Ground Penetrating Radar measurements). Research done with cooperation with University of Iceland and supported by the European Space Agency, Third Party Miassions. Overwiew of results of RADATSAT-2 (16 Mar 2018; Fine Quad Pol) classification of south part of Langjökull. Black line - contour of Langjökull; other colours - different scattering properties of SAR microwaves. For more details please contact Barbara Barzycka (bbarzycka@us.edu.pl).

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