Permafrost monitoring System of thermistors (temperature strings with loggers) to monitor the ground thermal state Precise data on the thermal state of the frozen ground is one of the key missing components of the environmental monitoring at the research stations spread across Spitsbergen. The CRIOS project will allow us to equip the newly established borehole with precise temperature strings that will record ground thermal changes over the next couple of years. A system of temperature strings will be used in the monitoring of the thermal state of permafrost in drilled boreholes. Devices were tested in severe weather and are commonly used for permafrost monitoring by other research groups working in polar regions. Site Information The borehole near the UMK station in Kaffioyra was located at the existing meteorological garden, about 100 m from the shoreline. The drilling was carried out on 20-21.07.2023. The substrate is dominated by loose sandy-gravel beach sediments. A large amount of fine material and the formation of a core in a small part of the hole made it possible to reach a depth of 10.0 m below sea level. 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)

Permafrost monitoring System of thermistors (temperature strings with loggers) to monitor the ground thermal state Precise data on the thermal state of the frozen ground is one of the key missing components of the environmental monitoring at the research stations spread across Spitsbergen. The CRIOS project will allow us to equip the newly established borehole with precise temperature strings that will record ground thermal changes over the next couple of years. A system of temperature strings will be used in the monitoring of the thermal state of permafrost in drilled boreholes. Devices were tested in severe weather and are commonly used for permafrost monitoring by other research groups working in polar regions. On the coastal section selected for drilling at Calypsobyen, the bedrock contains siltstone and sandstone forming relict abrasion platforms, which are currently covered by loose sand and gravel beach sediments. The borehole was located near the mouth of the Scott River (right bank), at a distance of about 75 m from the shoreline and 900 m from the station. After stopping the drilling progress again at 5 m below sea level, a decision was made to install a string in the third hole. 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 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)

Point cloud collected using the Riegl VZ®-6000 long-range terrestrial laser scanner. The TLS survey was carried out on 15th August 2021. The dataset is the result of relative and absolute registration of four point clouds. The dataset is the supplement to the paper: Błaszczyk, M.; Laska, M.; Sivertsen, A.; Jawak, S.D. Combined Use of Aerial Photogrammetry and Terrestrial Laser Scanning for Detecting Geomorphological Changes in Hornsund, Svalbard. Remote Sens. 2022, 14, 601. https://doi.org/10.3390/rs14030601

In the years 2009-2019, 49 samplings (shallow drilling or snowpits) were made on the glacier during the spring measurement campaigns in order to determine the bulk snow density and SWE. The average density of snow cover ranges from 386 to 447 kg/m3. The dataset includes part of the results from the project “Hindcasting and projections of hydro-climatic conditions of Southern 350 Spitsbergen” (grant no. 2017/27/B/ST10/01269) financed by the Polish National Science Centre, “Arctic climate system study of ocean, sea ice, and glaciers interactions in Svalbard area”—AWAKE2 (Pol-Nor/198675/ 17/2013), supported by the National Centre for Research and Development within the Polish–Norwegian Research Cooperation Programme and the SvalGlac—Sensitivity of Svalbard glaciers to climate change, the ESF Project, the project Integrated Arctic 355 Observing System (INTAROS)- Horizon 2020, the ice2sea 7th FP projects. The studies were carried out as part of the scientific activity of the Centre for Polar Studies (University of Silesia in Katowice) with the use of research and logistic equipment of the Polar Laboratory of the University of Silesia in Katowice.

Downwelling longwave flux in air measurements from AWS located on the Werenskioldbreen. The sensors are installed on a mast that is mounted in the glacier ice. During the season, the distance between the glacier's surface and the sensors increases. The station is serviced at least once a year between March and April.

DEMs from WorldView-2 and Pléaides were extracted using the Rational Function Model (RFM). To improve images orientation, one ground control points (GCPs) was used for each stereo pair. Data format: grid (2m), UTM 33X / EGM 2008. DEMs were developed in OrthoEngine module of PCI Geomatica 2016 with the low level of detail and mountainous type of relief.

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.

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.

High-resolution orthomosaic derived from aerial images captured in 2020 over Hornsund, Svalbard by Dornier aircraft. The spatial resolution of the orthomosaic is 0.087 m. Aerial images for the area were provided by the SIOS through a dedicated call of proposals (https://sios-svalbard.org/AirborneRS). The dataset is the supplement to the paper: Błaszczyk, M.; Laska, M.; Sivertsen, A.; Jawak, S.D. Combined Use of Aerial Photogrammetry and Terrestrial Laser Scanning for Detecting Geomorphological Changes in Hornsund, Svalbard. Remote Sens. 2022, 14, 601. https://doi.org/10.3390/rs14030601