Impacts of Degrading Ice‐Wedges on Ground Temperatures in a High Arctic Polar Desert System

Abstract

AbstractIce‐wedge ice is the most widespread type of massive ice found in the continuous permafrost zone. Polygonal networks of ice‐wedges drive environmental changes and feedback that will likely be exacerbated with future climate change. Recent decadal‐scale observations have shown that ice‐wedges are degrading rapidly within the entire Circum‐Arctic Region but observations of feedback associated with ground temperature regimes are still lacking in many areas. We present over a year's worth of field observations from an area with cold (−16.5°C), thick (>500 m) continuous permafrost and a mean annual air temperature of −19.7°C in the Canadian high Arctic. Topographic surveys, thaw depths, vegetation cover, soil moisture, and annual shallow (12 cm) ground temperature measurements were collected for seven ice‐wedge troughs and two polygon centers in a high‐centered polygon system. We show that geomorphic changes caused by ice‐wedge degradation generate new responses in soil moisture, vegetation cover, and snow distribution that create a mosaic of ground temperatures that range by 5.1°C for mean annual, 2.5°C in summer, and 15.2°C in winter between polygon‐centers and ice‐wedge troughs. Our results show that snow redistribution due to wind induces the cooling of polygon centers, thus promoting new thermal contraction cracking and ice‐wedge formation. We provide an example based on high‐resolution remote sensing data on how these ice‐wedge trough densities vary spatially in our study area. Capturing these fine scale geomorphic differences and resulting ground temperatures will be critical to accurately assess future changes of these common Arctic landscapes.