Permafrost monitoring on Yamal

Permafrost is an essential climate variable (ECV ). It is a subsurface phenomenon which cannot be directly measured with remotely sensed data. However, many parameters which influence the ground thermal regime and surface indicators can be captured with satellite data. This joint Russian-Austrian project utilizes satellite data indicating surface dynamics and properties of underlying permafrost in a region for which significant climate induced changes are predicted within this century. The objective of this project is to develop novel and refine existing methodologies for monitoring of permafrost, related land surface features and to advance our knowledge on permafrost landscape evolution by a synergistic analysis of these features, specifically thaw lakes, and active layer properties. The latter includes also investigation of detachment slides and impact of snow characteristics. The focus will be on a site on the Yamal peninsula underlain by permafrost. This area is monitored since 1988 by the Earth Cryosphere Institute and is close to a CALM site which contributes to the GTN-P network. This project will extent previous investigations with medium to coarse spatial resolution C- and Ku-band radar (SAR and scatterometer) analyses. Especially higher spatial resolution X-band SAR data in combination with field investigations of permafrost is expected to yield new information and thus enable innovation. The expertise of the team which includes geomorphology, geobotany, environmental sciences, cartography, remote sensing along with geocryology (permafrost science) provides the basis of a multidisciplinary approach. Coordinated knowledge exchange will ensure the appropriate selection of data for application in this particular area, development of the necessary processing of remotely sensed and ground data and interpretation of results. The feasibility of the project is assured by the comprehensive experience in environmental monitoring in the north of West Siberia of the Russian partner, access to a huge database of geographic data and knowledge concerning various permafrost features including activity of various relief-forming processes in the tundra of Yamal Peninsula, and extensive experience of the Austrian side in the use of the full range of remote sensing methods in permafrost environments. The expected results of the proposed interdisciplinary project are: - Development of a range of comprehensive methods combining field and remote sensing techniques to characterize permafrost parameters in the North of West Siberia and other permafrost regions (an integrated method), and - Application of the integrated method to the reference location on Yamal Peninsula.

The joint Austrian-Russian project enabled the development of novel monitoring methods of permafrost on the Yamal peninsula (Western Siberia) and the entire Arctic. The key to the success of the project have been joint field surveys, workshops and the diverse expertise of the team. It included geomorphology, geobotany, environmental sciences, cartography, remote sensing along with geocryology (permafrost science) providing the basis of a multidisciplinary approach. The team also included collaboration partners from Germany (Alfred Wegener Institute for Polar and Marine Research) and Finland (University of Eastern Finland). The intense exchange resulted in a number of peer-reviewed publications. The objective of this project was to advance our knowledge on permafrost landscape evolution, specifically thaw lakes and active layer properties. The Yamal peninsula is still located in a zone of continuous permafrost. Temperatures and depth of the annual thaw layer are increasing in this region due to climate change. The key to the understanding of future developments locally are spatial patterns of permafrost and associated features at the site. They have been mapped within the project by combination of in situ measurements (Russian expertise) and satellite data (Austrian expertise). Thaw lakes have been identified to undergo seasonal variations, what overlaps with long term changes and therefore impede long-term analyses with currently available satellite records. These lakes have shallow rims which are typical for permafrost regions and which are constantly modified by erosional activities along the shores (thaw slumps, active layer detachment slides etc.). All currently mapped features (in situ and from satellite) have been published in an openly accessible WebGIS. The infrastructure was supplied by the German collaboration partner AWI. Several lakes have been sampled by bathymetric measurements which served as calibration for a circumpolar mapping approach with satellite data. Synthetic Aperture Radar (SAR) data are able to detect ice that freezes to the ground. Lake freezing depth on central Yamal was determined to be about 1.5m during the reference year 2008. The novel dataset reveals areas with shallow thaw lakes across the entire Arctic. It serves as a reference dataset for future climate change studies and supports investigations on thaw lake development. An intensive vegetation and thaw depth survey has been carried out in order to interpret SAR signals of the land surface as proxy for permafrost local patterns. X-band SAR could be demonstrated to be applicable locally. Wetland features with specific soils that impact thaw depth could be shown to be mapped circumpolar with C-band SAR. An extensive review of currently available methods for land surface characterization in the Arctic was carried out and remaining challenges identified. The developed novel methods within the project are suitable to fill some of these gaps.