Influences and interactions of inundation, peat, and snow on active layer thickness

Active layer thickness (ALT), the uppermost layer of soil that thaws on an annual basis, is a direct control on the amount of organic carbon potentially available for decomposition and release to the atmosphere as carbon‐rich Arctic permafrost soils thaw in a warming climate. We investigate how key...

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Bibliographic Details
Published in:Geophysical research letters 2016-05, Vol.43 (10), p.5116-5123
Main Authors: Atchley, Adam L., Coon, Ethan T., Painter, Scott L., Harp, Dylan R., Wilson, Cathy J.
Format: Article
Language:English
Subjects:
Active layer
active layer thickness
ALT sensitivity
Amplification
Arctic soils
Atmosphere
Carbon
Climate
Climate change
Decomposition
Depth
ENVIRONMENTAL SCIENCES
Formations
GEOSCIENCES
Global warming
Hydrologic models
Hydrology
Interactions
Inundation
inundation and soil moisture
Landscape
Landscapes
Organic carbon
organic soil thermal properties
Parameter sensitivity
Parameters
Peat
Permafrost
Permafrost soils
Planetary Sciences
Saturation
Snow
Snow depth
Snowpack
Soil
Soil (material)
Soil investigations
Soil layers
Thaws
thermal hydrology
Thickness
Water content
Water depth
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Summary:Active layer thickness (ALT), the uppermost layer of soil that thaws on an annual basis, is a direct control on the amount of organic carbon potentially available for decomposition and release to the atmosphere as carbon‐rich Arctic permafrost soils thaw in a warming climate. We investigate how key site characteristics affect ALT using an integrated surface/subsurface permafrost thermal hydrology model. ALT is most sensitive to organic layer thickness followed by snow depth but is relatively insensitive to the amount of water on the landscape with other conditions held fixed. The weak ALT sensitivity to subsurface saturation suggests that changes in Arctic landscape hydrology may only have a minor effect on future ALT. However, surface inundation amplifies the sensitivities to the other parameters and under large snowpacks can trigger the formation of near‐surface taliks. Key Points Peat and organic‐rich soil will insulate permafrost from emerging environmental conditions ALT formation is weakly dependent to the amount of water on the landscape, but in combination with snow depth can trigger talik formation Snow depth will increase ALT and is codependant on inundation depth and peat thickness
ISSN:0094-8276
1944-8007
DOI:10.1002/2016GL068550