This raster dataset, in Cloud Optimized GeoTIFF format (COG), provides information on land surface changes at the pan-arctic scale. Multispectral Landsat-5 TM, Landsat-7 ETM+, Landsat-8 OLI, and Landsat-9 OLI-2 imagery (cloud-cover less than 70%, months July and August) was used for detecting disturbance trends (associated with abrupt permafrost degradation) between 2005 and 2024. For each satellite image, we calculated the Tasseled Cap multi-spectral index to translate the spectral reflectance signal to the semantic information Brightness, Greenness, and Wetness. In order to characterize change information, we calculated the linear trend of Brightness, Greenness, and Wetness over two decades at the individual pixel level, based on annually aggregated data. The final map product therefore contains information on the direction and magnitude of change for all three Tasseled Cap parameters at 30 m spatial resolution across the pan-arctic permafrost domain. Features detected include coastal erosion, lake drainage, infrastructure expansion, and fires. The general processing methodology was developed by Fraser et al. (2014) and adapted and expanded by Nitze et al. (2016, 2018). Here, we upscaled the processing to the circum-arctic permafrost region and applied it to the recent 20-year period from 2005 through 2024. The service covers the permafrost region up to 81° North: Alaska (USA), Canada, Greenland, Iceland, Norway, Sweden, Finland, Russia, Mongolia, and China. For Russia and China, regions not containing permafrost were excluded. The data have been processed in Google Earth Engine as part of the research projects ERC PETA-CARB, ESA CCI+ Permafrost, NSF Permafrost Discovery Gateway, and EU Arctic PASSION. The dataset is a contribution to the 'Pan-Arctic Requirements-Driven Permafrost Service' of the Arctic PASSION project (see References). Changes in the Tasseled Cap indices – Brightness, Greenness, and Wetness – are displayed in the image bands red, green, and blue, respectively. Here, coastal erosion (a trend of a land surface transitioning to a water surface) is depicted in dark blue tones, while coastal accretion (a trend of a water surface transitioning to a land surface) is depicted in bright orange colors. Drained lakes are shown in bright yellow or orange colors, depending on the soil conditions and vegetation regrowth. Fire scars are a further common feature, appearing in different colors depending on the time of the fire and the pre-fire land cover. The data can be explored via the Arctic Landscape EXplorer (ALEX; see References) and are available as a public web map service (WMS; see References), both hosted by Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research.
This raster dataset, in Cloud Optimized GeoTIFF format (COG), provides information on land surface changes at the pan-arctic scale. Multispectral Landsat-5 TM, Landsat-7 ETM+, and Landsat-8 OLI imagery (cloud-cover less than 80%, months July and August) was used for detecting disturbance trends (associated with abrupt permafrost degradation) between 2003 and 2022. For each satellite image we calculated the Tasseled Cap multi-spectral index to translate the spectral reflectance signal to the semantic information Brightness, Greenness, and Wetness. In order to characterize change information, we calculated the linear trend of the Brightness, Greenness and Wetness over two decades on the individual pixel level. The final map product therefore contains information on the direction and magnitude of change for all three Tasseled Cap parameters in 30m spatial resolution across the pan-arctic permafrost domain. Features detected include coastal erosion, lake drainage, infrastructure expansion, and fires. The general processing methodology was developed by Fraser et al. 2014 and adapted and expanded by Nitze et al. 2016 and Nitze et al. 2018. Here we upscaled the processing to the circum-arctic permafrost region and the recent 20-year period from 2003 through 2022. The service covers the permafrost region up to 81° North: Alaska (USA), Canada, Greenland, Iceland, Norway, Sweden, Finland, Russia, Mongolia, and China. For Russia and China, regions not containing permafrost were excluded. The data has been processed in Google EarthEngine within the research projects ERC PETA-CARB, ESA CCI+ Permafrost, NSF Permafrost Discovery Gateway, and EU Arctic PASSION. The dataset is a contribution to the 'Panarctic requirements-driven Permafrost Service' of the Arctic PASSION project (see references). Changes in the Tasseled Cap indices Brightness, Greenness, and Wetness are displayed in the image bands red, green, and blue, respectively. Here, coastal erosion (a trend of a land surface transitioning to a water surface) is depicted in dark blue colors, while coastal accretion (a trend of a water surface transitioning to a land surface) is depicted in bright orange colors. Drained lakes appear in bright yellow or orange colors, depending on the soil conditions and vegetation regrowth. Fire scars are a further common feature, which can appear in different colors, depending on the time of the fire and pre-fire land cover. The data can be explored via the Arctic Landscape EXplorer (ALEX, see references) and is available as a public web map service (WMS, see references), both hosted by Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research.
Schematic overview of a typical terrestrial and shallow-marine permafrost landscape during summer and winter. Permafrost is defined as ground that remains continuously at or below 0°C for at least two consecutive years; some 24% of the land surface in the northern hemisphere is classified as permafrost. This schematic figure (summer) pictures a terrestrial and shallow marine permafrost system. A permafrost landscape is characterized by its large heterogeneity with morphological permafrost-related features such as polygonal patterned ground with underlying ice wedges, thaw ponds, thermokarst lakes, and wetland areas. During winter, the terrestrial landscape is covered with snow, and water bodies and the ocean are typically covered with ice.The last pictures shows schematically the fluxes (not scaled) that occur between the terrestrial and marine environment and atmosphere.
Entstehung und Entwicklung der Permafrostgebiete sind eng mit dem globalen Klimawandel verknüpft. Vor allem der relativ warme diskontinuierliche Permafrost am Südrand der Permafrostverbreitung reagiert mit Auftauvorgängen sehr sensitiv auf Klimaänderungen. Die entsprechende Form des Permafrostabbaus ist der Thermokarst mit seinen geschlossenen, vermoorten und versumpften Hohlformen, die Durchmesser von wenigen Metern bis zu mehr als 1 km erreichen können. Folgen sind weitflächige Vernichtung der Taiga (Reduktion der CO2-Speicher) und Freisetzung von Methan und anderen klimarelevanten Spurengasen. Aus dendrochronologischen Vorarbeiten am Südrand des diskontinuierlichen Permafrostes in Westsibirien wissen wir, dass sich diese Thermokarsthohlformen beschleunigt seit der Mitte des letzten Jahrhunderts großflächig vergrößern. Wir haben Grund zur Annahme, dass die globale Klimaerwärmung der letzten Jahrzehnte zu diesem Effekt der Beschleunigung geführt hat. Aufgrund unterschiedlicher Größe gehen wir von unterschiedlichen Altern des Thermokarstes aus. Dendrochronologische und vegetationsgeographische Untersuchungen am Unterlauf des Ob in der Westsibirischen Tiefebene sollen Erkenntnisse darüber liefern, welche klimatischen (Temperatur, Niederschlag) und/oder anthropogenen Faktoren (Waldbrände, Brandrodung) den Rückgang des Permafrostes und damit die Bildung von Thermokarsthohlformen steuern.