Estimating active layer, ice-wedge and permafrost property distributions in Arctic ecosystem using electrical conductivity imaging

The estimation of the spatial distribution of active layer, ice-wedges and permafrost soil properties and of their link to landscape properties is critical for gaining an understanding of Arctic ecosystem functioning and for parameterizing process-rich models that simulate feedbacks to a changing climate. The objective of this study, which is part of the Next-Generation Ecosystem Experiments (NGEE-Arctic), is to develop advanced strategies for Arctic soil imaging and to investigate surface to subsurface interactions that may be used to parameterize mechanistic models. We concentrate our efforts at the NGEE study site located within the Barrow (AK) Environmental Observatory. We have collected many datasets at this site, including point measurements, airborne-based Lidar measurements and geophysical datasets collected using electromagnetic induction (EMI, which provides extensive spatial coverage) and electrical resistance tomography (ERT, which provides high-resolution information). Specific goals of our study include (i) development of a parameter-estimation approach that is adapted to explore the solution non-uniqueness inherent to EMI data, (ii) highresolution multi 2D ERT imaging of ice-wedges and active layer, and (iii) investigation of relations between subsurface properties and surface properties such as landform and drainage characteristics. The results suggest (i) the significant potential of using EMI and ERT data to characterize such environment at various scale and spatial coverage, (ii) the capability of the developed EMI parameter-estimation approach to infer conductivity variations in the active layer, and (iii) some preliminary relations between subsurface properties and landscape characteristics that can be used to extrapolate highresolution observations over large areas.