Evaluating ALOS-PALSAR for Ice Monitoring - What Can L-band do for the North American Ice Service?
The Canadian Ice Service (CIS), the U.S. National Ice Center (NIC), and the International Ice Patrol (IIP), partners in the North American Ice Service (NAIS), have individually and jointly used airborne and spaceborne synthetic aperture radar data extensively for almost three decades in their daily ice monitoring operations. SAR's unique ability to penetrate clouds and weather make these data invaluable to the NAIS' efficient environmental stewardship and safe operation in Canadian and U.S. waters. Since 1992, solely C-Band satellite radar has been in use as operational SAR missions such as ERS 1 & 2, RADARSAT-1, and Envisat ASAR have selected it as the band of choice. With the launch of RADARSAT-2 on December 2007 and approved plans for Sentinel-1, the NAIS intends to continue utilizing C-Band data in its daily operations. However, it is important to understand the unique and complementary capabilities of other SAR bands. The January 2006 launch of the JAXA ALOS satellite and present availability of L-band SAR data from its PALSAR instrument provides a unique opportunity to assess L-band data for application to ice monitoring. ALOS/PALSAR availability also provides the potential for examining the synergies between L-Band data and C-Band data available from the current and planned C-Band missions. The existing literature suggests that the use of different frequencies could be advantageous in certain ice conditions, which is of interest to the NAIS because of the vastness of the geographical area monitored annually and the associated variations in ice regimes and conditions. This paper summarizes the preliminary results of a NAIS evaluation of near-coincident C-Band (RADARSAT-1) and L-Band data sets collected in various ice regimes. Through both quantitative and qualitative analysis we attempt to identify the unique and complementary sea ice information PALSAR can provide. In doing so, we identify the role these data could play in the NAIS' operational programs, both in a complementary role to existing C-Band SARs and its potential as a contingency platform. This work will also help us better understand the potential for future possible multi-frequency SAR platforms.