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- Title
Control of Short‐Stature Vegetation Type on Shallow Ground Temperatures in Permafrost Across the Eastern Canadian Arctic.
- Authors
Evans, Sarah G.; Raberg, Jonathan H.; Crump, Sarah E.; Raynolds, Martha K.; Sugg, Margaret M.; Brodie, Alexander R.; Miller, Gifford H.
- Abstract
The Arctic has warmed three times the rate of the global average, resulting in extensive thaw of perennially frozen ground known as permafrost. While it is well understood that permafrost thaw will continue and likely accelerate, thaw rates are nonuniform due, in part, to the expansion of Arctic trees and tall shrubs that may increase ground temperatures. However, in permafrost regions with short‐stature vegetation (height < 40 cm), our understanding of how ground temperature regimes vary by vegetation type is limited as these sites are generally found in remote high‐latitude regions that lack in situ ground temperature measurements. This study aims to overcome this limitation by leveraging in situ shallow ground temperatures, remote sensing observations, and topographic parameters across 22 sites with varying types of short‐stature vegetation on Baffin Island, Canada, a remote region underlain by rapidly warming continuous permafrost. Results suggest that the type of short‐stature vegetation does not necessarily correspond to a distinct shallow ground temperature regime. Instead, in permafrost regions with short‐stature vegetation, factors that control snow duration, such as microtopography, may have a larger effect on evolving ground temperature regimes and thus permafrost vulnerability. These findings suggest that anticipating permafrost thaw in regions of short‐stature vegetation may be more nuanced than previously suggested. Plain Language Summary: Air temperatures across the Arctic are rapidly warming and causing perennially frozen ground known as permafrost to thaw. As permafrost thaws, it has the potential to accelerate global warming through carbon dioxide and methane release. Permafrost thaw rates vary from place to place due, in part, to the expansion of trees and tall shrubs, which is also occurring as the Arctic warms. This tall vegetation traps snow, which acts as a blanket and insulates the ground surface from cold air thawing permafrost. However, in places where permafrost occurs below shorter vegetation, our understanding of how vegetation influences permafrost thaw is lacking, largely because these regions of the Arctic are difficult to access. This study sheds light on this shortcoming by leveraging environmental data across permafrost sites with shorter vegetation on Baffin Island, Canada. Contrary to previous findings, we suggest that the exact type of short vegetation is not always the primary control on ground temperatures. Instead, ground temperatures in these regions seem to be controlled by how long snow is on the ground, due to other factors like small depressions or wind buffering. These findings help us anticipate permafrost thaw in remote, rapidly warming permafrost regions with short‐stature vegetation. Key Points: We examine the role of short‐stature vegetation type on shallow ground temperatures in a remote region underlain by continuous permafrostContrary to prior results, the type of short‐stature vegetation does not necessarily correspond to a distinct ground temperature regimeUnderstanding controls on snow duration is more critical than classifying short‐stature vegetation types when predicting permafrost thaw
- Subjects
ARCTIC regions; BAFFIN Island (Nunavut); EARTH temperature; PERMAFROST; TEMPERATURE control; ATMOSPHERIC temperature; GLOBAL warming; SNOW cover
- Publication
Journal of Geophysical Research. Biogeosciences, 2022, Vol 127, Issue 7, p1
- ISSN
2169-8953
- Publication type
Article
- DOI
10.1029/2022JG006941