ALBERT

Description: Based on the map of landscapes and permafrost conditions in Yakutia (Merzlotno-landshaftnaya karta Yakutskoi0 ASSR, Gosgeodeziya SSSR, 1991), rasterized maps of permafrost temperature and active-layer thickness of Yakutia, East Siberia were derived. The mean and standard deviation at 0.5-degree grid cell size are estimated by assigning a probability density function at 0.001-degree spatial resolution. Spatial pattern of both variables are dominated by a climatic gradient from north to south, and by mountains and the soil type distribution. Uncertainties are highest in mountains and in the sporadic permafrost zone in the south. The maps are best suited as a benchmark for land surface models which include a permafrost module.

Description: Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here we present, a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM,ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (-0.69%), Western Alaska (-2.82%), and Kolyma Lowland (-0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e. upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.

Description: The dataset presents the radiocarbon ages (with standard deviation ±) from thermokarst lake sediment cores from the Yukechi Alas, Siberia. The sediment cores were taken from an alas lake (YUK15-YU-L7) and a yedoma lake (YUK15-YU-L15). Raw, calibrated and rounded calibrated ages are presented. Measurements were carried out in the AWI MICADAS Laboratory in Bremerhaven. Calibrations were performed according to Stuiver et al. (2017) using CALIB 7.1 software and the IntCal13 calibration curve.

Description: These data are laboratory results for carbon characteristics (TOC, TC, TN, C/N ratio, stable carbon isotope ratio, radiocarbon ages from bulk organic material), sediment characteristics (mass specific magnetic susceptibility (4.65 kHz & 0.465 kHz), grain size measurements 〈 1 mm) and ice characteristics (sample mass (wet), sample mass (dry), absolute ice content, stable oxygen and hydrogen isotope ratios of pore ice, pH and conductivity of pore ice). Two cores were analyzed: Yedoma core YED1 N 61.75967° / E 130.47438°; h = 218 m asl total length: 22,35 m (recovery 21,13 m) ice wedge included from ~7,14 to ~9,5 m Alas core Alas1 drilled in the drained part of a thermokarst lake basin N 61.76490° / E 130.46503° total length: 19,80 m (recovery 11,14 m) unfrozen conditions from ~1,6 to ~7,5 m Both cores were drilled in March 2015 from dry land surface in a joint expedition of the ERC PETA-Carb poject and the DFG project UL426/1-1 "Short and long-term thermokarst dynamics due to climate changes and human impacts in Central Yakutia, Siberia (2013-2016)". The sample names are compiled as [campaign]-[core] [drive] [depth (top)] - [depth (bottom)]. Age calibration was done with Calib7.10. Grain size percentages were calculated using GRADISTAT (Blott and Pye, 2001). Missing carbon isotope and C/N ratio values are a result of carbon and/or nitrogen contents below detection limit (0.1 wt%). Missing ice characteristics values are a result of dry and/or fine material obstructing the pore ice/water extraction.

Description: This file presents the detailed description of two deep permafrost cores from the Yukechi Alas landscape in Central Yakutia, Russia. These data were recorded during subsampling of the cores and are based on visual and haptic impression. The core "YED1" is a Yedoma permafrost core. Core was obtained during field work in March 2015.