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).

Time-lapse cameras In order to determine the state of coverage of the area, e.g. period of snow cover on a tundra, the extent of the glacier front, etc., it is necessary to perform photographic imaging at a specific time interval. This will allow for precise diagnosis of snow conditions. The camera is installed at the main entrance to the NCU Polar Station. The lens is pointed in a westerly direction, towards Prins Karls Forland CRIOS – Cryosphere Integrated Observation Network on Svalbard Project financed from the EEA Financial Mechanism 2014-2021 operated by the National Science Centre in Poland Agreement no. UMO-2022/43/7/ST10/00001 to a predefined project no. 2022/43/7/ST10/00001 Project period: 08.09.2022 - 30.04.2024 (2029)

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

Time-lapse cameras In order to determine the state of coverage of the area, e.g. period of snow cover on a tundra, the extent of the glacier front, etc., it is necessary to perform photographic imaging at a specific time interval. This will allow for precise diagnosis of snow conditions. CRIOS – Cryosphere Integrated Observation Network on Svalbard Project financed from the EEA Financial Mechanism 2014-2021 operated by the National Science Centre in Poland Agreement no. UMO-2022/43/7/ST10/00001 to a predefined project no. 2022/43/7/ST10/00001 Project period: 08.09.2022 - 30.04.2024 (2029)

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.

Englacial water pressure was recorded by placing HOBO 250-Foot Depth Water Level Data Loggers in the center of Crystal Cave (N77°02' E15°34', 174 m) channel system (Hansbreen glacier). Data loggers were set to record values every 30 minutes, resampled to daily in post-processing, and have a resolution of 2.55 kPa for a typical error of 3.8 cm water level. Water pressure was converted in water level. Sensor was placed in the cave by drilling anchor points into the ice above a vertical shaft, then hanging cables down in the center of conduit. Stabilization cables were used to keep sensors from attaching to and freezing into ice walls by manually rappelling down to the sensor and attaching it to three horizontal cables, anchored into the ice walls at about 120 degrees apart. Senor was installed in Crystal Cave at about 100 m total distance from the cave entrance, in ice about 74 m thick. The sensor was installed 28 m above the glacier bed and 46 m below the ice surface.

Glaciers facies (ice, superimposed ice, firn) extents of Hansbreen, Storbreen and Flatbreen delivered from unsupervised classifications of single, dual and fully-polarimetric SAR data (ALOS-2 PALSAR, RADARSAT-2, Sentinel-1, ERS-2 SAR) between 2008 and 2018. 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 bbarzycka@us.edu.pl.

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).

The annual velocity of Hansbreen in the period 2007–2015 is determined at stake No. 4 located approximately 3.5 km upstream of the glacier terminus (15°28`E, 77°02`N). Monitoring of the glacier is conducted by Institute of Geophysics Polish Academy of Science. The stake position was measured by the differential GPS receiver at the turn of each year (December/January) (with a horizontal accuracy of ±4 cm). Velocity along the Hansbreen terminus in 2009 and 2015 is processed from repeated terrestrial laser scanning in August 2009 and August 2015. Values of displacements of the same features along the calving front (distinctive edges of crevasses) for approximately two weeks were provided with an accuracy of around 10 cm. 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.

Air temperature is provided by AWS 4 (N77°02' E15°38', 183 m). Air temperature comes from a Campbell Scientific 107 sensor at +/- 0.1° C resolution and sampled every 10 minutes, averaged to daily resolution in post-processing.