Interpretation of First-year Sea Ice Parameter by Multi-frequency and Multi-polarized Synthetic Aperture Radars in Kongsfjorden, Svalbard: Recent Results from the from the Spring 2009 Measurement

Abstract

Large regions of the Polar Oceans are covered by sea ice. The ice has a profound impact on the exchange of heat, momentum, and matter between the ocean and the atmosphere, on the solar albedo of the ocean, and on deep ocean circulation. Remote sensing by Synthetic aperture radar(SAR) is the most important method of observing sea ice on a regional scale independent of cloud cover and daylight conditions. In Arctic Ocean, its repeat cycle is less than half day, and when multiple satellite used, the SAR observation would be possible in two or three hours.Sea ice a complex, polycrystalline composite of pure ice with random brine, air pockets and snow layers. Its backscatter depends on many physical parameters such as surface roughness, salinity, air, layers. Its backscatter depends on many physical parameters, such as surface roughness, salinity, air, crystal structure, snow cover and others(W. Dierking. et al, 2003). Two major mechanisms: (1) surface scattering and (2) volume scattering are taken into consideration in describing the dependence of the backscatter coefficient on several sea ice properties. Fast ice in Kongsfjorden of Svalbard consists solely of seasonal ice, i.e. ice that melts completely in summer. Each autumn and winter, new fast ice forms. Sea ice formed during the current winter contains typically from 6 to 10 psu salinity, enough to limit the penetration of C-band radar waves into the ice to a few centimeters(Shokr, 1998). Therefore, the backscatter from first-year ice is dominated by surface scattering. In this study, fully polarized SAR images on ALOS-PALSAR(Advanced Land Observing Satellite – Phased Array L-band SAR) is used over Kongsfjorden of Svalbard . The decomposition methods are defined in monostatic radar system and the influence of sea ice properties such as surface roughness or volume structure on the observed radar signature is explained, also considering environmental effects.