Speaker
Dr
Stefano Tebaldini
(Politecnico di Milano)
Description
Characterisation of snow and ice plays a pivotal role in understanding and monitoring changes in the global climate and ecosystem. Monitoring inland snowpack properties is a most important issue for the management of water resources, especially in the present context of climate change. The properties of sea ice and its snow cover control the amount of solar radiation reflected to the atmosphere, absorbed within snow and ice, and transmitted into the ocean beneath the ice.
In this paper we present scientific investigations of both ice and snow based on high resolution Synthetic Aperture Radar (SAR) Tomography (TomoSAR).
TomoSAR has been largely considered in recent years for forestry applications as it entails a fundamental advantage over traditional (i.e.: 2D) SAR imaging, namely the possibility to see the vertical structure of the imaged volume, to be afterwards employed as a robust basis for validation and development of physical models.
The instrumentation to be employed for this scope is the Ground-Based Synthetic Aperture Radar (GB-SAR) developed by the SAPHIR team at IETR, University of Rennes I, hereinafter referred to as IETR GB-SAR. Such a system can be operated at frequency bands ranging from C-Band to Ka-Band. The system is able to form a 2D aperture by moving transmitting and receiving antennas along a rail that can be vertically displaced, achieving a vertical resolution of few centimeters.
Data are presented from the ESA campaign AlpSAR, in the Austrian Alps, dedicated to snowpack investigations, and from surveys carried out over Kattfjord, Tromsø, Norway, where sea ice was the focus of the analysis.
For both snowpack and sea ice the images produced by the GBSAR revealed a multi-layered structure. In many cases the backscattered from the bottom layers was observed to dominate the one from the surface and near subsurface by over 20 dB. This result was found to be largely independent of the incidence angle. GBSAR images also turned out to provide sensitivity to propagation velocity within the snowpack, as revealed by the apparent depth variation with respect to the incidence angle. This effect was used to assess propagation velocity according to a simple model based on Snell law.
Primary author
Dr
Stefano Tebaldini
(Politecnico di Milano)
Co-authors
Mr
Badreddine Rekioua
(Université de Rennes 1)
Prof.
Laurent Ferro-famil
(Université de Rennes 1)
Mr
Temesgen Gebrie Yitayew
(University of Tromso)
