Space-borne Synthetic Aperture Radar (SAR) and GeophysicalApplications: Polarimetric Imaging and Monitoring of Earth’s Surface
Processes
WOOIL M. MOON
Satellite Research Centre, Research Institute of Oceanography (RIO), Seoul National
University, Seoul 151-742 KOREA and Geophysics, The University of Manitoba, Winnipeg,
MB R3T 2N2 CANADA( Email: wmoon@cc.umanitoba.ca and wmoon@snu.ac.kr )The focus of Earth Science research has recently been shifting from the traditionaland classical geology and geophysics disciplines because of increasing concerns
about Earth’s rapidly changing environment, which is in part believed to be closely
linked to anthropogenic origins. One of the effective tools for continuously
monitoring the changes in global scale is the space-borne remote sensing technique.
In particular, microwave remote sensing systems have become very effective andsought after tools, because of their continuous imaging and monitoring capabilities
of Earth, without sun light under increasing cloud covers and unpredictable weather
conditions globally.
The Synthetic Aperture Radar (SAR), or microwave imaging radar, isbecoming a more sophisticated, powerful and cost effective tool for continuously
monitoring changes in various Earth’s surface processes, without the dependency on
solar illumination or on weather conditions. The signal wavelength of SAR systems
is sufficiently long, compared to the visible bands of the electromagnetic spectrum,that the phase information from backscattered SAR signal can be accurately resolvedfor various interferometric applications. The phase and wave number informationfrom SAR data can be effectively resolved in both cross-track and along-trackgeometries, making it a unique space-borne sensor that can monitor and measurevery small changes and deformation at the surface of Earth. The space-borne SAR
systems can thus continuously observe the Earth’s surface with very high spatial
resolution independent of solar illumination or of weather conditions. Theseadvantages have been and can be widely utilized in various Earth system science
applications.
The new generation of space-borne SAR systems, including RADARSAT-2(launched in Dec. 2007), TerraSAR-X (launched in July 2007) and ALOS (PALSAR)(launched in January, 2006), now all operate in the fully polarimetric mode. These
space-borne fully polarimetric SAR systems in C-, X-, and L-bands now make itpossible for us to observe the Earth’s surface processes in multiple frequencies andin fully polarimetric mode simultaneously.

2This paper will discuss the new space-borne SAR applications on land, tidal
flats between the land mass and ocean and ocean applications, including monitoringof active volcanoes, using differential InSAR techniques, land subsidence mapping
using PS-InSAR, coastal wind measurements from co-pol SAR data, soil moisturemapping, ocean current and wave imaging and measurements using ATI (AlongTrack Interferometry) and polarimetric decomposition theory and applications offully polarimetric SAR data.
RADARSAT-2 (CSA, Canada), along with TerraSAR-X (DLR, Germany),and ALOS (JAXA, Japan), all provide us with a new research tool. All weather
capabilities of these satellites without sun light also make them ideal tools formonitoring natural disasters such as volcanic eruptions, earthquakes and landslides,in addition to the biomass estimation and Earth’s surface cover classification. A fullrange of new application capabilities of these new satellites in Earth system scienceand geophysics in general will be discussed and explored.