Application of field spectrometry and remote sensing for permafrost surface studies in the Laptev Sea lowland (Lena River Delta)

• Main Authors: Ulrich, Mathias, Grosse, Guido, Chabrillat, S., Schirrmeister, Lutz
• Format: Conference Object
• Language: unknown
• Published: 2008
• Subjects: Arctic; Laptev Sea; laptev; lena delta; lena river; permafrost; Thermokarst; Tundra
• Online Access: https://epic.awi.de/id/eprint/19643/; https://epic.awi.de/id/eprint/19643/1/Ulr2008c.pdf; https://hdl.handle.net/10013/epic.31486; https://hdl.handle.net/10013/epic.31486.d001

The monitoring of permafrost coastal landscapes is a cornerstone of the quantification of future environmental changes and their impacts on Arctic coastal lowlands of the Lena Delta, which link the arctic continental region to the Laptev Sea. Thawing of permafrost might cause massive landscape changes due to thermokarst and enhanced release of greenhouse gasses from the large carbon storage of frozen deposits. In addition, current quantities of carbon and other nutrients in sediments, likely to be mobilized by ever increasing coastal erosion, are only crudely known. Remote sensing and spatial data analysis are ideal tools to detect, study, and quantify changes and/or mapping carbon contents in the Arctic tundra. For a successful interpretation of such data, considerable basic knowledge on the properties of these landscapes is required. This includes the characterization of vegetation, soils, geomorphology, and spectral surface properties. A variety of field investigations and lab analyses (image and spectra processing, terrain modelling, spatial data analysis) were carried out for the assessment of periglacial surface properties in the Lena Delta. A portable field spectrometer (ASD FieldSpec ProFR) was used for the acquisition of more than 500 field spectra from 19 sites in the delta. 12 different surface classes were extracted from these spectra. Additionally, various satellite data (Landsat 7 ETM+, CHRIS-Proba) were used for manual mapping and automatic classification of surface properties. The discrete acquisition of field spectral properties in high spectral and spatial resolution from periglacial features allows a validation of the interpretation of coarser resolution satellite data. The analysis of field spectral data in combination with geomorphological, pedological and vegetation data then allowed us to characterize and classify periglacial surfaces and land cover units in the Lena Delta. The resulting surface types indicate significant differences in surface properties between the delta main terraces, and thus a good spectral separation of these units. These results indicate that the variability of landcover, and hence of subsurficial carbon contents is far greater than previously thought. They provide a prospective insight into the modus operandi required to adequately and accurately quantify the quantities of nutrients available in the Arctic coastal zone