ALBERT

Description: Dense time series of stripmap RADARSAT-2 data acquired in the Multilook Fine mode were used for detecting and mapping the extent of selective logging operations in the tropical forest area in the northern part of the Republic of the Congo. Due to limited radiometric sensitivity to forest biomass variation at C-band, basic multitemporal change detection approach was supplemented by spatial texture analysis to separate disturbed forest from intact. The developed technique primarily uses multi-temporal aggregation of orthorectified synthetic aperture radar (SAR) imagery that are acquired before and after the logging operations. The actual change analysis is based on textural features of the log-ratio image calculated using two SAR temporal composites compiled of SAR scenes acquired before and after the logging operations. Multitemporal aggregation and filtering of SAR scenes decreased speckle and made the extracted textural features more prominent. The overall detection accuracy was around 80%, with some underestimation of the area of forest disturbance compared to reference based on optical data. The user’s accuracy for disturbed forest varied from 76.7% to 94.9% depending on the accuracy assessment approach. We conclude that change detection utilizing RADARSAT-2 time series represents a useful instrument to locate areas of selective logging in tropical forests.

Description: Permafrost cannot be directly detected from space, but many surface features of permafrost terrains and typical periglacial landforms are observable with a variety of EO sensors ranging from very high to medium resolution at various wavelengths. In addition, landscape dynamics associated with permafrost changes and geophysical variables relevant for characterizing the state of permafrost, such as land surface temperature or freeze-thaw state can be observed with space-based Earth Observation. Suitable regions to examine environmental gradients across the Arctic have been defined in a community white paper (Bartsch et al. 2014). These transects have been revised and adjusted within the DUE GlobPermafrost initiative of the European Space Agency. The ESA DUE GlobPermafrost project develops, validates and implements Earth Observation (EO) products to support research communities and international organisations in their work on better understanding permafrost characteristics and dynamics. Prototype product cases will cover different aspects of permafrost by integrating in situ measurements of subsurface properties and surface properties, Earth Observation, and modelling to provide a better understanding of permafrost today. The project will extend local process and permafrost monitoring to broader spatial domains, support permafrost distribution modelling, and help to implement permafrost landscape and feature mapping in a GIS framework. It will also complement active layer and thermal observing networks. Both lowland (latitudinal) and mountain (altitudinal) permafrost issues are addressed. The status of the Permafrost Information System and first results will be presented. Prototypes of GlobPermafrost datasets include: - Modelled mean annual ground temperature by use of land surface temperature and snow water equivalent from satellites - Land surface characterization including shrub height, land cover and parameters related to surface roughness - Trends from Landsat Time series over selected transects - For selected sites: subsidence, ground fast lake ice, land surface features and rock glacier monitoring

Description: Permafrost cannot be directly detected from space, but many surface features of permafrost terrains and typical periglacial landforms are observable with a variety of EO sensors ranging from very high to medium resolution at various wavelengths. In addition, landscape dynamics associated with permafrost changes and geophysical variables relevant for characterizing the state of permafrost, such as land surface temperature or freeze-thaw state can be observed with spaceborne Earth Observation. Suitable regions to examine environmental gradients across the Arctic have been defined in a community white paper (Bartsch et al. 2014, hdl:10013/epic.45648.d001). These transects have been revised and adjusted within the DUE GlobPermafrost initiative of the European Space Agency. The ESA DUE GlobPermafrost project develops, validates and implements Earth Observation (EO) products to support research communities and international organisations in their work on better understanding permafrost characteristics and dynamics. Prototype product cases will cover different aspects of permafrost by integrating in situ measurements of subsurface and surface properties, Earth Observation, and modelling to provide a better understanding of permafrost today. The project will extend local process and permafrost monitoring to broader spatial domains, support permafrost distribution modelling, and help to implement permafrost landscape and feature mapping in a GIS framework. It will also complement active layer and thermal observing networks. Both lowland (latitudinal) and mountain (altitudinal) permafrost issues are addressed. The status of the Permafrost Information System and first results will be presented. Prototypes of GlobPermafrost datasets include: Modelled mean annual ground temperature by use of land surface temperature and snow water equivalent from satellites Land surface characterization including shrub height, land cover and parameters related to surface roughness Trends from Landsat time-series over selected transects For selected sites: subsidence, ground fast lake ice, land surface features and rock glacier monitoring

Description: Permafrost cannot be directly detected from space, but many surface features of permafrost terrains and typical periglacial landforms are observable with a variety of EO sensors ranging from very high to medium resolution at various wavelengths. In addition, landscape dynamics associated with permafrost changes and geophysical variables relevant for characterizing the state of permafrost, such as land surface temperature or freeze-thaw state can be observed with space-based Earth Observation. Suitable regions to examine environmental gradients across the Arctic have been defined in a community white paper (Bartsch et al. 2014). These transects have been updated within the ESA DUE GlobPermafrost project. The ESA DUE GlobPermafrost project develops, validates and implements Earth Observation (EO) products to support research communities and international organisations in their work on better understanding permafrost characteristics and dynamics. Prototype product cases will cover different aspects of permafrost by integrating in situ measurements of subsurface properties and surface properties, Earth Observation, and modelling to provide a better understanding of permafrost today. The project will extend local process and permafrost monitoring to broader spatial domains, support permafrost distribution modelling, and help to implement permafrost landscape and feature mapping in a GIS framework. It will also complement active layer and thermal observing networks. Both lowland (latitudinal) and mountain (altitudinal) permafrost issues are addressed. The selected transects and first results will be presented. This includes identified needs from the user requirements survey, a review of existing land surface products available for the Arctic as well as prototypes of GlobPermafrost datasets, and the permafrost information system through which they can be accessed.

Description: Permafrost is an important component of the Cryosphere, which is affected by rapid warming of the Arctic. The degradation and thaw of permafrost in vertical as well as lateral directions results in a reduction of permafrost in high latitudes and high altitudes. Since permafrost affects the ecosystem conditions of the about 23 million square kilometer large permafrost region, its loss has strong effects on hydrology, geomorphology, biogeochemistry, and biota. In addition, permafrost soils store about 1500 Gt of organic carbon, about twice the amount currently in the atmosphere and hence changes in permafrost will likely have impacts well beyond local scales. Remote sensing has become an essential tool for quantitatively detecting and monitoring changes in permafrost and associated landscapes. The European Space Agency (ESA) has supported permafrost-focused remote sensing activities in two recent projects, ESA DUE Permafrost (2009-2012) and the ESA GlobPermafrost (2016-2019; http://www.globpermafrost.info). The first ESA DUE Permafrost project with spatial overage of the Northern Hemisphere developed, validated and implemented Earth Observation to support research communities and international organizations in their work on better understanding permafrost characteristics and dynamics. Now, the GlobPermafrost project expands on this successful approach by including both polar hemispheres as well as mountain permafrost regions. Products in the new project will cover different aspects of permafrost by integrating in situ measurements of subsurface properties and surface properties, Earth Observation, and modelling. Currently, the GlobPermafrost team is creating prototype remote sensing derived datasets for defined product and user groups. Selected users will be able to access the usability and validity of the products and provide feedback back to the GlobPermafrost team. The feedback from the Users Groups will be integrated into optimized remote sensing products until they have achieved a final state. To bring the resulting data products closer to the permafrost user communities, the Permafrost Information System (PerSys) has been conceptualized as an Open Access geospatial data dissemination and visualization portal for Earth Observation, i.e. remote sensing derived datasets produced within the GlobPermafrost project. The prototype and final remote sensing products and their metadata will be visualized in the PerSys WebGIS, described and searchable via the PerSys Data Catalogue. The WebGIS visualization is managed via the AWI WebGIS Infrastructure maps@awi (http://maps.awi.de) relying on OGC-standardized Web Mapping Service (WMS) and Web Feature Service (WFS) technologies for data display and visualization. The PerSys WebGIS projects allow visualisation of raster and vector products such as land cover classification, Landsat multispectral index trend datasets, lake and wetland extents, InSAR-based land surface deformation maps, rock glacier velocity fields, spatially distributed permafrost model outputs, and land surface temperature datasets. Each of these WebGIS projects is adapted to the spatial scale of the specific products, ranging from local to hemispherical coverage. The PerSys Data Catalogue will provide the metadata and the access to all mature-state and final-state GlobPermafrost products. PerSys can be accessed through the GlobPermafrost project webpage. PerSys is also a core component of the Arctic Permafrost Geospatial Centre (APGC), a geodata portal for permafrost launched within the framework of the ERC PETA-CARB project at the Alfred-Wegener-Institut Helmholtz Zentrum für Polar and Meeresforschung. The APGC framework features a range of permafrost-specific geospatial data projects, including PerSys, and will allow searching for project-specific geospatial data by tags, keywords, data type and format, licence type, or by location. PerSys will be launched within APGC in early 2017. In addition, the Open Access data library PANGAEA as a certified ICSU member will serve as permanent archive for the GlobPermafrost final products, providing permanent Digital Object Identifiers (DOIs) for each dataset archived. The ESA DUE Permafrost final product data set is already published under DOI doi:10.1594/PANGAEA.780111. The final GlobPermafrost remote sensing products published in PANGAEA will remain visualised in the PerSys WebGIS and catalogued and made searchable and accessible via the PerSys Data Catalogue.

Description: Permafrost regions are highly sensitive to climate changes. The monitoring of key variables and identification of relevant-processes is of topmost importance in these environments. ESA DUE GlobPermafrost (www.globpermafrost.info) provides a remote sensing data service for permafrost research and applications. This service was extended by permafrost modelling (time series), implemented in the new ESA CCI+ Permafrost project (2018-2021). The service comprises of the generation of remote sensing products for various regions and spatial scales as well as the specific infrastructures for visualisation, dissemination and access to datasets - PerSys. PerSys is the ESA GlobPermafrost geospatial information service for publishing and visualisation of information and data products to the public. Data products are described and searchable in the PerSys data catalogue (apgc.awi.de), and data visualisation employs the AWI WebGIS-infrastructure maps@awi (http://maps.awi.de), a highly scalable data visualisation unit within the AWI data-workflow framework O2A, from Observation to Archive. maps@awi WebGIS technology supports the project-specific visualisation of raster and vector data products of any spatial resolution and remote sensing origin. This is a prerequisite for the visualisation of the wide range of GlobPermafrost remote sensing products like: Landsat multispectral index trends (Tasseled Cap Brightness, Greeness, Wetness; Normalized Vegetation Index NDVI), Arctic land cover (e.g. shrub height, vegetation composition), lake ice grounding, InSAR-based land surface deformation, rock glacier velocities and a spatially distributed permafrost model output with permafrost probability and ground temperature per pixel. We established several WebGIS projects for the adaption to products specific spatial scales. For example, the WebGIS ‘Arctic’ visualises the Circum-Artic products. Highly resolved data products for rock glacier movements are visualised on regional scales in the WebGIS projects ‘Alps’, ‘Andes’ or ‘Central Asia’. The PerSYS WebGIS also visualises the stations of the WMO GCOS ground monitoring networks of the permafrost community: the Global Terrestrial Network for Permafrost GTN-P managed by the International Permafrost Association IPA. The PerSYS WebGIS has been continuously adapted in close co-operation with user at user workshops and at conferences and the International Permafrost Association (IPA).