Modeling trajectories of degradation of ice rich permafrost landscapes


Contact
moritz.langer [ at ] awi.de

Abstract

Thawing of permafrost triggers a wide range of morphodynamic processes which magnitude and pace direly relate to the ground ice content. Already induced or completed degradation processes are visible as intriguing geomorphological features of permafrost landscapes such as thermokarst lakes, thermo erosion gullies, thaw slumps, and degraded ice wedged polygons. The formation of these features is, on the one hand, strongly controlled by the topographical and hydrological landscape properties. On the other hand, these landscape properties are explicitly modified by permafrost thaw and the accompanying morphodynamics. Consequently, a wide range of positive and negative feedback mechanisms can lead to either accelerated permafrost degradation (due to e.g. ponding water) or permafrost preservation (due to e.g. enhanced drainage and insulation). Based on different modeling exercises using the permafrost – land surface model CryoGrid, we demonstrate the high sensitivity of permafrost landscapes to small morphodynamic landscape changes on the one side and permafrost stability on the other side. Therefore, we present simulations of ice wedged polygons, thaw slumps, and thermokarst lakes and follow their different trajectories of degradation under a warming climate. Our preliminary results indicate that already minor changes in the lateral flow rates of water and/or matter can result in different pathways of permafrost degradation leading to different landscape morphologies. This finding may have strong implications for biogeochemical processes such as the decomposition of organic soil components.



Item Type
Conference (Poster)
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
AGU Fall Meeting 2018, 10 Dec 2018 - 14 Dec 2018.
Eprint ID
49124
Cite as
Langer, M. , Nitzbon, J. , Schneider von Deimling, T. and Oehme, A. (2018): Modeling trajectories of degradation of ice rich permafrost landscapes , AGU Fall Meeting 2018, 10 December 2018 - 14 December 2018 .


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