The Hidden Image of Thawing Permafrost: project overview and first results of the radar polarimetric analysis

Abstract

Permafrost in the Northern hemisphere is rapidly warming in the context of climate change. The degradations associated to this trend pose several threats, locally to landscapes, infrastructures and settlements, and globally as permafrost is a potential source of greenhouse gazes in the carbon cycle. Different remote sensing methods can be used to monitor permafrost, most of them relying on surface observables which are then related to the ground thermal state. The Hidden Image of Thawing Permafrost (HIT Permafrost) project however aims at mapping directly subsurface properties using remote sensing data. We are aiming in particular at estimating soil properties such as ground ice content, layer composition and frozen versus non-frozen state of the soil in the sense of a vertical layering. To achieve this, the project relies on expert knowledge, ground measurements and remote sensing data combined using innovative techniques and models. The data has been collected over a particular test site, Trail Valley Creek, located in the Mackenzie River Delta (Canada). Airborne campaigns were performed simultaneously by the Alfred Wegener Institute (AWI) and the German Aerospace Center (DLR) in summer 2019 and winter 2019, providing a unique dataset of respectively optical photographs and LIDAR, and multimodal Synthetic Aperture Radar. We will give an overview of the HIT Permafrost project and present some first results of the radar polarimetric analysis.