Coast Watch by Satellite Remote Sensing 

Dr Antony K. Liu (Department of Environmental Informatics, National Taiwan Ocean University / NASA Goddard Space Flight Center)

Abstract
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Satellite remote sensing with repeated coverage is the most efficient method
to monitor and study coastal environment, marine productivity, underwater
bathymetry, and pollution.  The mapping of mesoscale ocean features in the
ocean is one of major potential applications for satellite data. Ocean
features such as eddies, fronts, upwelling, reefs/atolls, and ice edges can
result in the changes in water properties, mixing, or transport which is
critical for marine environment, and ship navigation. The ability of
Synthetic Aperture Radar (SAR) for monitoring surface signatures of swells,
wind fronts, bottom features, oil slicks, eddies and typhoon has been amply
demonstrated. The combined use of IR (AVHRR), ocean color (SeaWiFS, MODIS),
and SAR (ERS-1/2, Envisat, Radarsat) data can provide frequent high
resolution coverage of the coastal area for the evolution study of oceanic
and atmospheric processes.  As an example, during the Bering Sea
Fisheries-Oceanography Coordinated Investigation (FOCI) field test,
simultaneous satellite SAR data, in-situ measurements from moorings and ship
operations have been collected for coordination and sampling. The ice edge
location has been found to be highly correlated with climate change and
highly productive for fishery feeding, and SAR images are very useful for
tracking the movement of the ice edge and floes in the marginal ice zone.
Also, ships and their wakes are commonly observable in the high-resolution
SAR imagery from satellite.  Detection of ships and of ship wakes by means
of remote sensing can be useful in the areas of national defense
intelligence, shipping traffic, and fishing enforcement as demonstrated by
the Vessel Monitoring System (VMS).   The underwater bathymetry has been
mapped by satellite remote sensing (SAR, SPOT, and Landsat) in the Spratly
Islands of South China Sea (SCS) for ship navigation.  As demonstrated by
these examples, the use of SAR-derived observations to track eddies, fronts,
ships, ice edges, bathymetry, oil slicks, and typhoon can supply valuable
information for the protection of environment.  Finally, a Taiwan coast
watch network has been proposed to monitor the Kuroshio and East Coast
environment with CODAR, satellites, moorings, bottom mounted cables, and
ships.