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Identification of wetlands in central SiberiaInstitute of Photogrammetry and Remote Sensing, Vienna University of Technology, Austria Wetlands in sub-arctic and boreal regions play an important role for greenhouse gas accounting. Their extent and role as carbon sink or source is still uncertain, especially in Siberia. This research was carried out within the framework of the SIBERIA II project, which deals with multi-sensor concepts for greenhouse gas accounting in northern Eurasia. The region of interest is located in central Siberia and covers more than 3 million kmē. Approximately 100 ENVISAT ASAR WS scenes per growing season have been utilized to derive permanent water bodies and wetlands. The use of the SARscape module for ENVI allowed a precise and fast pre-processing of these images. Tasks involved DEM based georeferencing and radiometric correction. Normalization, classification and mosaic-ing has been performed using batch functionalities beside functions directly available via the ENVI user interface. Permanent and seasonal inundation patterns as well as soil moisture changes in peatlands have been investigated. The example figures show water bodies maps and a peatland map from the eastern rim of the west Siberian lowlands. A combination of sub-arctic climate, topography and permafrost ice content on Taimyr is causative for the abundance of small and shallow lakes. They are associated with the distribution of tundra wetlands where high amounts of methane are released into the atmosphere. Carbon is sequestered in the peatlands of the middle Taiga. This region is located in the transition zone of permafrost and thus sensitive to climate change.
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Figure 1: Left: Geocoded, radiometric
corrected and normalized ASAR WS image. Small lakes are abundant on the Taimyr peninsula.
They form important freshwater ecosystems and represent tundra wetlands which feature high
methane emissions. Right: Georeferenced mosaic-ing of classified ASAR WS images from 27th
of August 2003. 