WITH recent reductions in Arctic ice extent, there has been growing economic interest in shipping and natural resource extraction in the Arctic [1]. To support safe Arctic operations and navigation in ice-infested waters, timely high- resolution information of the ice coverage is crucial [2]. In this paper, we focus on ice concentration, which is defined as the percentage of ice coverage over a given spatial area.
Satellite sensors are used as the main data source for ice monitoring in the Arctic region. Due to the frequent cloud coverage and long periods with little sunlight, optical remote sensing technology cannot generate continuous observations in the Arctic. Instead, passive microwave and synthetic aperture radar (SAR) sensors are commonly used [3], both of which can generate observations regardless of the weather conditions (cloud, rain) and sunlight. Passive microwave sensors detect radiation emitted by the target. A large footprint is normally required to have sufficient energy for a measurement. This constrains the spatial resolution of the passive microwave data, which is normally above 4 km. In contrast, SAR transmits radiation to the Earth and measures the portion of backscattered to the sensor. The spatial resolution of SAR im- agery used for ice mapping is normally less than 100 m, which is much finer than the resolution of passive microwave imagery