Synergy within MARSAIS
MARSAIS combines data from SAR sensors with those acquired by either optical or thermal infrared sensors. The aim of this is a better understanding of physical and bio-physical processes in the coastal zone than could be achieved with the help of SAR analysis alone.
Example: Eddies
Eddies are rotating water masses that are often formed along regions where two water masses with different physical properties meet. The water body of which the eddy consists can thus originate from the waters of either side of the frontand carry their properties. Accordingly, one often refers to a warm-core eddy (wamer water body rotating in a cooler environment) or a cold-core eddy (cooler water body rotating in a warmer environment). SAR however, cannot see these temperature differences directly. The mechanisms which can make eddies visible in SAR imagery are in fact the same ones producing SAR signatures of current fronts.
Examples 1 and 2 show two sites in the Japan Sea. In the first case, co-incident images from ERS-2 SAR and AVHRR show signatures of a warm-core eddy. In the second example, the ERS-2 SAR and AVHRR images were acquired 4 days apart but still show corresponding signatures of a warm-core eddy.
Example 3 shows images from the Scottish north coast and demonstrates the benefits of synergy with respect to spatial coverage.
Example 4 shows a SAR image of the northern Aegean Sea and four corresponding AVHRR images which were acquired over three days, displaying the temporal development of the eddy.
The Currents Product gives more information on SAR imaging of eddies.
Examples:
Algorithm:
The UoS Synergy Toolkit enables joint display and analysis of SAR and other satellite data.