Beschreibung: We present a comprehensive inventory of retrogressive thaw slumps (RTS) for six study sites in the Russian High Arctic covering an area of more than 600 km². The sites are located on the Novaya Zemlya Archipelago, Kolguev Island, Bol'shoy Lyakhovsky Island, and Taymyr Peninsula in ice-rich permafrost characterized by either buried glacial ice or syngenetically formed Yedoma permafrost deposits. This data publication contains geospatial polygon vector files of the individual mapped slumps across multiple time slices. The mapping was performed on multispectral imagery of very high-resolution satellite sensors, including PlanetScope (3m ground resolution), RapidEye (5m), Pléiades (0.5m), and SPOT (1.5m). Cloud free images were acquired between 2011 and 2020 and exist for annual or close-to-annual time steps depending on their availability. Additional data sets such as the ArcticDEM, the Esri Satellite base map, and Tasseled Cap Landsat Trends were used to support the mapping process. The identification and digitization of thaw slumps as polygons (in UTM coordinate reference system) was performed in QGIS 10.3. A total number of 3466 individual RTS were mapped between 2011 or 2013 and 2020. In addition, for the coastal slumps, change distances from headwalls and bluff bases were calculated in ArcMap 10.5 using the Digital Shoreline Analysis System (DSAS) tool version 5 over the study period (2011/2013-2020). Very high-resolution imagery for this study was kindly provided by ESA through Third Party Mission proposal TPM4-ID-54054. We recieved access to the RapidEye imagery via the RapidEye Science Archive (RESA) initiative in the scope of our project 'Thaw Dynamics of Retrogressive Thaw Slumps from High Resolution Images in Siberia (RTStrendr )'. The PlanetScope imagery was recieved in the scope of our project ' Artificial Intelligence for Cold Regions (AI-CORE)'.

Beschreibung: Total Suspended Matter (TSM), Particulate Organic Carbon (POC) and its isotopic composition were measured in water samples from the Lena River and its Delta (Sardakhskaya branch). Samples were taken in summer 2019 during the CACOON expedition (Fuchs et al., 2021a, b and 2022) along ~ 1600 km transect from Yakutsk downstream to the Lena Delta disembogue into the Laptev Sea. Water was filtered through pre-combusted (4.5 hours, 450 °C) and pre-weighed glass fiber filters (GF/F Whatman, 0.75 µm membrane, Ø 2.5 cm) for TSM content (difference in weights between dried filters with TSM and pre-weighed empty filters), POC concentration and δ13C-POC (Sercon 20-20 isotope ratio mass spectrometer coupled to an Automated Nitrogen Carbon Analyzer), ∆14C-POC analysis (accelerator mass spectrometer achieved on a Mini Carbon Dating System) and relative OC content in TSM (calculated by dividing the sample POC content by the TSM content). Our aim was to characterize POC along the Lena River over a transect from upper reaches of the Lena River north to the Lena delta in order to decipher the distribution, main sources, and transformation of POC on its way from the permafrost catchment to the Arctic Ocean.