Ice super-saturated permafrost deposits, formed syn-genetically during the Late Pleistocene, are widely distributed in coastal lowland regions of Arctic NE Siberia. The ice content of the silty deposits (up to 160 weight-percent compared to dry mass) makes them very susceptible for large-area thawing and surface subsidence under warmer climate conditions. Hence, extensive thermokarst developed in this region during the Holocene. Generally, thermokarst is a significant factor in periglacial relief generation and landscape evolution. Additionally, the analysis of thermokarst-related transformation processes in periglacial landscapes is very important regarding the expected deep thawing of permafrost and the release of formerly frozen organic carbon in form of green house gases under a global warming scenario. To evaluate the Holocene thermokarst development and estimate possible future developments in the region, it is necessary to calculate and understand its actual extent. For this investigation, Landsat-ETM remote sensing data from the Lena-Anabar coastal lowland is used as an instrument for up-scaling local field data. Classes of different geomorphological units are discriminated with supervised classification algorithms based on various surface parameters like vegetation, relief, and soil moisture. These classes allow the characterization and quantification of periglacial landscape units with a focus on thermokarst features in the investigated area. The spatial distribution of identified thermokarst structures and their relationship to other geomorphological and hydrological features are analysed within a geographical information system using a digital elevation model and geomorphological parameters derived from the DEM. As result, quantitative and qualitative parameters for thermokarst structures in this Laptev Sea coastal region are derived.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL6-Earth climate variability since the Pliocene
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL7-From permafrost to deep sea in the Arctic