Control of Short‐Stature Vegetation Type on Shallow Ground Temperatures in Permafrost Across the Eastern Canadian Arctic
Control of Short‐Stature Vegetation Type on Shallow Ground Temperatures in Permafrost Across the Eastern Canadian Arctic
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DOI：
10.1029/2022jg006941
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发表时间：
2022-06
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影响因子：
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通讯作者：
S. Evans;J. Raberg;S. Crump;M. Raynolds;M. Sugg;Alexander R. Brodie;G. Miller
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作者：
S. Evans;J. Raberg;S. Crump;M. Raynolds;M. Sugg;Alexander R. Brodie;G. Miller
北极变暖的速度是全球平均水平的三倍，导致被称为永久冻土的常年冻土广泛融化。虽然众所周知，永久冻土融化将继续并可能加速，但融化速度并不均匀，部分原因是北极树木和高大灌木的扩张可能会提高地面温度。然而，在具有矮小植被(高度40厘米)的永久冻土地区，我们对地温状况如何随植被类型变化的了解有限，因为这些地点通常位于偏远的高纬度地区，缺乏现场地温测量。这项研究旨在通过利用加拿大巴芬岛上22个具有不同类型矮小植被的地点的现场浅层地温、遥感观测和地形参数来克服这一限制，巴芬岛是一个偏远地区，被快速升温的持续冻土覆盖。结果表明，矮小植被的类型并不一定对应于明显的浅层地温状况。相反，在植被矮小的永冻区，控制降雪持续时间的因素，如微地形，可能会对不断演变的地温制度产生更大的影响，从而对永冻土的脆弱性产生更大的影响。这些发现表明，预测矮小植被地区的永久冻土融化可能比之前提出的更微妙。
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.