From multidecadal to interannual and seasonal remote sensing of thermokarst dynamics in Siberian permafrost landscapes


Contact
Frank.Guenther [ at ] awi.de

Abstract

Although a subsurface phenomenon, permafrost creates distinct features on the land surface which can be observed using remote sensing data. This is especially true for the East Siberian Arctic where ice-rich permafrost is abundant in the geological subsurface and only protected by a thin layer of organic soils. In the Lena River Delta, deeper seasonal thaw during increasingly frequent warm summers does not only result in irreversible loss of ground ice and subsequent land subsidence, but also in discharge of soil organic carbon that was previously fixed in permafrost. To characterize the dynamics of thawing permafrost and its impacts on landscapes, hydrology, and emission of methane and carbon dioxide we analyse optical remote sensing time series from various sensors. Local field measurements (meteorology, ground temperature, geodetic surveys) during several recent Russian-German Arctic expeditions complement our remote sensing studies and help differentiating factors causing relief and land cover changes. While previous studies concentrated on general inventory of thermokarst landforms, higher temporal resolution of contemporary image acquisitions provides unique information for the understanding of seasonal processes, such as ice-on and ice-off on thermokarst lakes, shore erosion on delta channels, water level changes and drainage events in lakes, and wettening/drying of thermokarst-affected areas. Ground truth data provides the basis for calibration and correction of 21 RapidEye scenes (level 1B) from 2014 using a bundle block adjustment procedure. Next steps will include extraction of seasonal variations of band metrics such as NDVI which we will compare to decadal Landsat time series of landcover change and multitemporal, photogrammetrically-derived digital elevation models in order to identify signatures and trends typical for permafrost thaw related processes on the surface. Our approach will allow assessment of rates and short-term changes in thermokarst dynamics and landscape evolution. In addition, the derived data will be valuable for permafrost-thaw model parameterization.



Item Type
Conference (Talk)
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Not peer-reviewed
Publication Status
Published
Event Details
7. RESA Workshop "Nutzung von RapidEye-Daten im Kontext der Synergie mit anderen Sensoren und in Vorbereitung auf künftige Missionen, 29 Apr 2015 - 30 Apr 2015, DLR Bonn-Oberkassel.
Eprint ID
37856
Cite as
Günther, F. , Grosse, G. , Fuchs, M. , Nitze, I. and Overduin, P. , Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung (2015): From multidecadal to interannual and seasonal remote sensing of thermokarst dynamics in Siberian permafrost landscapes , 7. RESA Workshop "Nutzung von RapidEye-Daten im Kontext der Synergie mit anderen Sensoren und in Vorbereitung auf künftige Missionen, DLR Bonn-Oberkassel, 29 April 2015 - 30 April 2015 .


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info:eu-repo/grantAgreement/EC/FP7/338335


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