ALBERT

Description: Thematic Open Access data portals foster and support an open data culture in order to reduce knowledge gaps and data uncertainty. Here we present the Arctic Permafrost Geospatial Center (APGC), which provides open access, high quality spatial data in the field of permafrost research. The distribution and easy access of a wide range of permafrost-related data products supports multi-scale and interdisciplinary analysis of combined field, remote sensing and modelling data. The APGC mission is to provide data that is of high usability, significance and impact, and to facilitate data discovery, data view and supports metadata documentation and exchange via the APGC data catalogue at https://apgc.awi.de/. The catalogue structure can host data models of varying themes, formats, and spatial and temporal extents. Data can be searched by interactively selecting locations on a base map and by many predefined metadata filters. Data can be downloaded directly through a link to the publishing data repository such as PANGAEA. The Catalogue is based on the open source CKAN catalogue architecture, which allows on-the-fly access to catalogued data in QGIS. The APGC currently features over 200 selected datasets from projects such as ERC PETA-CARB, ESA GlobPermafrost, and others. Data products provide information about surface and subsurface permafrost characteristics in the Arctic, Antarctica, or mountain permafrost areas, e.g., soil temperatures, soil carbon, ground ice, land cover, vegetation, periglacial landforms, subsidence and more. Collections of datasets allow users to easily get an overview of the spatial distributions of datasets or their availability in different formats. An additional WebGIS application allows users to explore most of the data interactively (https://maps.awi.de). Data submissions are evaluated according to the following access criteria: permafrost focus, broader significance and impact, open access, high quality, and available metadata.

Description: Uncertainty in carbon cycling in terrestrial ecosystems contributes to overall uncertainty in Earth System Models. In particular, polar terrestrial ecosystems are understudied. Here, we focus on optical and radar remote sensing approaches to understand above-ground carbon dynamics related to vegetation as primary producers in tundra permafrost landscapes. In the ongoing Russian-German research cooperation and joint field expeditions we evaluate the applicability of remote sensing for assessing vegetation stocks and short-term fluxes in the Lena River Delta in the Siberian Arctic. New spaceborne satellite missions such as Sentinel-1, Sentinel-2 and ESA Data User Element DUE Permafrost provide useful services and data for this investigation. i) We evaluated and ground-truthed circumarctic-harmonized geospatial products of land cover and vegetation height from the ESA GlobPermafrost program for the Lena Delta region. The remote sensing products were derived from radar Sentinel-1 and optical Sentinel-2 satellite data. They are findable in the Arctic Permafrost Spatial Center (APGC) (apgc.awi.de) and are published under 10.1594/PANGAEA.897916, [Titel anhand dieser DOI in Citavi-Projekt übernehmen] and 10.1594/PANGAEA.897045 [Titel anhand dieser DOI in Citavi-Projekt übernehmen] . ii) We classified land cover using Sentinel-2 data based on in-situ vegetation data and optimized on biomass and wetness regimes. iii) We investigated the applicability of different land cover products for upscaling in-situ field-based biomass estimates to landscape-scale above-ground vegetation carbon stocks. iv) We investigated how disturbances enhance above-ground vegetation carbon cycling using in-situ data on vegetation community, biomass, and stand age and including remote sensing observations. Our research suggests that subarctic land cover needs to show biomass and moisture regimes to be applicable. Sentinel-1 and Sentinel-2 satellite missions provide adequate spatial high resolution to upscale vegetation communities and biomass in permafrost tundra landscapes. Biomass is providing the magnitude of the carbon flux, whereas stand age is irreplaceable to provide the cycle rate. High disturbance regimes such as floodplains, valleys, and other areas of thermo-erosion are linked to high and rapid carbon fluxes compared to low disturbance on Yedoma upland tundra and holocene terraces with polygonal tundra.

Description: Thematic Open Access data portals foster and support an open data culture in order to reduce knowledge gaps and data uncertainty. We here present the Arctic Permafrost Geospatial Center (APGC), which provides open access, high quality geospatial data in the field of permafrost research. The APGC mission is (i) to provide data that is of high usability, significance and impact, and (ii) to facilitate data discovery, data view and supports metadata documentation and exchange via a data catalogue (http://apgc.awi.de/). The Data Catalogue is based on the open source CKAN data catalogue architecture, which uses the metadata standard DCAT. The catalogue structure can host a variety of data models of varying themes, format, spatial and temporal extents. Data is documented according to the fair data principles. Each catalogue entry has a data abstract, data preview and extensive metadata that can be downloaded in RDF/XML-, JSON- or Turtle-format. Data can be searched by location – using spatial keywords or by interactively selection locations on a base map. Data can further be searched by product type, project, tags, keywords, license type, or data format. Data can be downloaded directly via link to the publishing data repository such as PANGAEA. APGC, initially supported by the ERC PETA-CARB and the ESA GlobPermafrost projects currently features over 100 selected datasets mainly from these projects. A WebGIS application is available for most of these data sets, which allows users to explore the data interactively (http://maps.awi.de). Data provide information about surface and subsurface permafrost characteristics in the Arctic, Antarctica, or mountain permafrost areas, e.g., soil temperatures, soil carbon, ground ice, land cover, vegetation, periglacial landforms, subsidence and more. Data include in-situ measurements, earth observation, and modelling and are provided in vector or raster format. New data submissions to the catalogue are evaluated according to the following access criteria: permafrost focus, significance and impact, access, quality, and metadata. APGC invites submissions from both individual users as well as project consortiums.

Description: Permafrost is an Essential Climate Variable (ECV) within the Global Climate Observing System (GCOS), which is characterized by subsurface temperatures and the depth of the seasonal thaw layer. Complementing ground-based monitoring networks, the Permafrost CCI project funded by the European Space Agency (ESA) 2018-2021 will establish Earth Observation (EO) based products for the permafrost ECV spanning the last two decades. Since ground temperature and thaw depth cannot be directly observed from space-borne sensors, we will ingest a variety of satellite and reanalysis data in a ground thermal model, which allows to quantitatively characterize the changing permafrost systems in Arctic and High-Mountain areas. As recently demonstrated for the Lena River Delta in Northern Siberia, the algorithm uses remotely sensed data sets of Land Surface Temperature (LST), Snow Water Equivalent (SWE) and landcover to drive the transient permafrost model CryoGrid 2, which yields ground temperature at various depths, in addition to thaw depth. For the circumpolar CCI product, we aim for a spatial resolution between 10 and 1km, but ensemble runs will be performed for each pixel to represent the subgrid variability of snow and land cover. The performance of the transient algorithm crucially depends on the correct representation of ground properties, in particular ice and organic contents. Therefore, the project will compile a new subsurface stratigraphy product which also holds great potential for improving Earth System Model results in permafrost environments. We report on simulation runs for various permafrost regions and characterize the accuracy and ability to reproduce trends against ground-based data. Finally, we evaluate the feasibility of future “permafrost reanalysis” products, exploiting the information content of various satellite products to deliver the best possible estimate for the permafrost thermal state over a range of spatial scales.

Description: A Permafrost Information System (PerSys) has been setup as part of the GlobPermafrost ESA DUE GlobPermafrost project (2016-2019, www.globpermafrost.info). This includes a data catalogue as well as a WebGIS, both linked to the Pangaea repository for easy data access. The thematic products available include InSAR-based land surface deformation maps, rock glacier velocity fields, spatially distributed permafrost model outputs, land surface properties and changes, and ground-fast lake ice. Extended permafrost modelling (time series) is implemented in the new ESA CCI+ Permafrost project (2018-2021), which will provide the key for our understanding of the changes of surface features over time. Special emphasis in CCI+ Permafrost will be on the evaluation and development of land surface models to gain better understanding of the impact of climate change on permafrost and land-atmosphere exchange. Additional focus will be on documentation of kinematics from rock glaciers in several mountain regions across the world. We will present an overview on technical developments made within GlobPermafrost and demonstrate its utility and challenges for an area prone to change of permafrost features. We will focus on the central Yamal Peninsula and the unusually warm years of 2012 and 2016. Conditions of 2012 triggered widespread retrogressive thaw slumps and the development of a gas emission crater. Thaw slumps have been reactivated in 2016, the first year with extensive coverage of Sentinel-1 as well as Sentinel-2 data. We present the documentation of these developments based on InSAR subsidence, Landsat trend analyses, ground fast lake ice, Sentinel-2 landcover information as well as a time series of the first version of ground temperatures from the ESA CCI+ Permafrost project. While landcover documents the occurrence of disturbances, InSAR provides insight into soil properties and impacts of unusually warm conditions during the unfrozen period. These space-based observations have been evaluated by in situ measurements at the long-term monitoring site Vaskiny Datchi. Ground fast lake ice and ground temperature modelling results provide additional insight into interannual variability.