DOI: 10.5194/tc-15-1399-2021
论文题名: Effects of multi-scale heterogeneity on the simulated evolution of ice-rich permafrost lowlands under a warming climate
作者: Nitzbon J. ; Langer M. ; Martin L.C.P. ; Westermann S. ; Schneider Von Deimling T. ; Boike J.
刊名: Cryosphere
ISSN: 19940416
出版年: 2021
卷: 15, 期: 3 起始页码: 1399
结束页码: 1422
语种: 英语
英文关键词: climate change
; heterogeneity
; land surface
; landscape change
; landscape evolution
; permafrost
; simulated annealing
; simulation
; thermokarst
; Arctic
英文摘要: In continuous permafrost lowlands, thawing of ice-rich deposits and melting of massive ground ice lead to abrupt landscape changes called thermokarst, which have widespread consequences on the thermal, hydrological, and biogeochemical state of the subsurface. However, macro-scale land surface models (LSMs) do not resolve such localized subgrid-scale processes and could hence miss key feedback mechanisms and complexities which affect permafrost degradation and the potential liberation of soil organic carbon in high latitudes. Here, we extend the CryoGrid 3 permafrost model with a multi-scale tiling scheme which represents the spatial heterogeneities of surface and subsurface conditions in ice-rich permafrost lowlands. We conducted numerical simulations using stylized model setups to assess how different representations of micro-and meso-scale heterogeneities affect landscape evolution pathways and the amount of permafrost degradation in response to climate warming. At the micro-scale, the terrain was assumed to be either homogeneous or composed of ice-wedge polygons, and at the meso-scale it was assumed to be either homogeneous or resembling a low-gradient slope. We found that by using different model setups and parameter sets, a multitude of landscape evolution pathways could be simulated which correspond well to observed thermokarst landscape dynamics across the Arctic. These pathways include the formation, growth, and gradual drainage of thaw lakes; the transition from low-centred to high-centred ice-wedge polygons; and the formation of landscape-wide drainage systems due to melting of ice wedges. Moreover, we identified several feedback mechanisms due to lateral transport processes which either stabilize or destabilize the thermokarst terrain. The amount of permafrost degradation in response to climate warming was found to depend primarily on the prevailing hydrological conditions, which in turn are crucially affected by whether or not micro-and/or meso-scale heterogeneities were considered in the model setup. Our results suggest that the multi-scale tiling scheme allows for simulating ice-rich permafrost landscape dynamics in a more realistic way than simplistic one-dimensional models and thus facilitates more robust assessments of permafrost degradation pathways in response to climate warming. Our modelling work improves the understanding of how micro-and meso-scale processes affect the evolution of ice-rich permafrost landscapes, and it informs macro-scale modellers focusing on high-latitude land surface processes about the necessities and possibilities for the inclusion of subgrid-scale processes such as thermokarst within their models. © 2021 Copernicus GmbH. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164773
Appears in Collections: 气候变化与战略
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作者单位: Permafrost Research, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany; Geography Department, Humboldt-Universität zu Berlin, Berlin, Germany; Department of Geosciences, University of Oslo, Oslo, Norway
Recommended Citation:
Nitzbon J.,Langer M.,Martin L.C.P.,et al. Effects of multi-scale heterogeneity on the simulated evolution of ice-rich permafrost lowlands under a warming climate[J]. Cryosphere,2021-01-01,15(3)