Investigating Bedrock through Canopy Structure, Organization and Connectivity of an Arctic Watershed

Improving understanding of Arctic ecosystem functioning and parameterization of process-rich models that simulate feedbacks to a changing climate require advances in quantifying ecosystem properties, from within the bedrock to the top of the canopy. In Arctic regions having significant elevation gradients and subsurface heterogeneity (bedrock, permafrost, ground ice), quantifying surface and subsurface structure, organization and connectivity of watershed elements is particularly challenging yet is critical for predicting the storage and flux of carbon in a changing climate. In this study, we evaluate linkages between physical properties (incl. fraction of soil constituents, bedrock depth, permafrost characteristics), hydrological conditions and geomorphic characteristics. This study takes place in a Seward Peninsula Watershed near Nome AK, which is characterized by an elevation gradient, extensive bedrock, and discontinuous permafrost. We use a multi-method acquisition strategy to characterize below and above ground properties and their linkages, including point-scale measurements, electrical resistivity tomography, seismic refraction and UAS-based low-altitude aerial imaging. Data integration and analysis is supported by numerical approaches that simulate dynamic hydrological and thermal processes. Overall, this study enables the identification of watershed structure and the links between various soil (incl., water content, temperature, electrical conductivity), landscape properties (incl. wetness conditions, vegetation, topographic metrics) and the bedrock/permafrost distribution and characteristics in a representative Arctic watershed. Low-altitude aerial imaging shows promise to extend the landscape organization analysis approach to larger regions in the Arctic. The obtained information about organization and connectivity of the landscape is expected to be useful for improving predictions of Arctic ecosystem feedbacks to climate.