Is There any Landscape Signature of Permafrost?

Permafrost influences hillslope and channel processes by controlling water availability for sediment transport and soil erosion, which changes with warming. I study how permafrost landscapes are shaped by climate by quantifying the pace and pattern of erosion across time and space. We find that low hilltop curvatures and drainage densities are universal topographic signatures of permafrost processes, seen in both the modern Arctic and landscapes underlain by permafrost during the Last Glacial Maximum. Landscapes that were colder during the Last Glacial Maximum have higher erosion rates than warmer landscapes with similar topographies, consistent with field and remote measurements from modern landscapes showing high sediment movement rates driven by wetness rather than steepness. We are mapping permafrost drainage networks, which are distinct from landscapes that do not have frozen ground, to understand their formation and changes under shifting climate conditions, as disturbances may indicate changes in the thermal state of permafrost. We also explore thermal channelization of suprapermafrost flowpaths to explain Arctic drainage patterns and vegetation trends.

Speaker: Joanmarie Del Vecchio, College of William & Mary

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