PolSAR-Ap: Exploitation of Fully Polarimetric Data for Glacier and Sea Ice Characterization

• Main Authors: Parrella, Giuseppe, Marino, Armando, Hajnsek, Irena
• Format: Conference Object
• Language: unknown
• Published: ESA 2013
• Subjects: Radarkonzepte; Sea ice
• Online Access: https://elib.dlr.de/84605/

Monitoring glaciers and sea-ice is a primary task to understand and quantify climate change. At the same time, it is a major topic in remote sensing due to the difficulty of performing frequent in-situ expeditions [1, 2]. In this sense, microwave sensors like Synthetic Aperture Radars (SARs) have a great potential in cryospheric observations since they can operate in absence of solar illumination (i.e. during Polar nights) and with almost any weather conditions. Moreover, long-wavelength (e.g. L- band) SAR systems are capable to penetrate several meters deep into ice bodies. Hence, they are sensitive to the ice surface characteristics as well as to sub-surface structures (including in some cases the lower ice-water interface of sea-ice). Unfortunately, the description of the backscattering behavior of glacier and sea ice is particularly challenging. For this reason, many scientists moved toward systems able to increase the amount of information acquired. In this context, polarimetry plays a key role, because it is able to enhance the discrimination capability of the observed target, solving many ambiguities revealed in single polarization images [3]. The polarimetric response of a target is highly sensitive to its orientation along the Line of Sight LoS (i.e. the direction of propagation of the wave). Therefore, the same target with different orientations may give a substantially different response in SAR images. For the case of sea-ice, this in general will lead to wrong classification (since a different backscattering will be observed). By exploitingfully polarimetric data, it is possible to estimate the orientation of the target and remove its effects [3, 4]. Several methodologies were proposed for this correction; here the one based on the circular polarizations is exploited since it can be applied to distributed targets (coherency matrix) [4]. If the Pauli basis is exploited, any orientation along the LoS can be mathematically represented by a rotation matrix (along the first axis HH+VV). The circular ...