Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate

Interactions and feedbacks between abundant surface waters and permafrost fundamentally shape lowland Arctic landscapes. Sublake permafrost is maintained when the maximum ice thickness (MIT) exceeds lake depth and mean annual bed temperatures (MABTs) remain below freezing. However, declining MIT sin...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Arp, Christopher D., Jones, Benjamin M., Grosse, Guido, Bondurant, Allen C., Romanovsky, Vladimir E., Hinkel, Kenneth M., Parsekian, Andrew D.
Format: Article in Journal/Newspaper
Language:unknown
Published: 2016
Subjects:
Arctic
Talik
Round Lake
Ice
permafrost
Alaska
Online Access:https://epic.awi.de/id/eprint/41737/
https://doi.org/10.1002/2016GL068506
https://hdl.handle.net/10013/epic.48602
Description
Summary:Interactions and feedbacks between abundant surface waters and permafrost fundamentally shape lowland Arctic landscapes. Sublake permafrost is maintained when the maximum ice thickness (MIT) exceeds lake depth and mean annual bed temperatures (MABTs) remain below freezing. However, declining MIT since the 1970s is likely causing talik development below shallow lakes. Here we show high-temperature sensitivity to winter ice growth at the water-sediment interface of shallow lakes based on year-round lake sensor data. Empirical model experiments suggest that shallow (1m depth) lakes have warmed substantially over the last 30years (2.4°C), withMABT above freezing5 of the last 7years.This is incomparison to slower ratesofwarming in deeper (3 m) lakes (0.9°C), with already well-developed taliks. Our findings indicate that permafrost below shallow lakes has already begun crossing a critical thawing threshold approximately 70 years prior to predicted terrestrial permafrost thaw in northern Alaska.

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