Nested Radar Systems for Remote Coastal Observations

Advances in radar technology now allow the observation of sea surface features at multiple scales, from kilometers,
down to metres. In the same manner that nested models are used at different resolutions, nested radars of different
frequencies can be used to provide data on sea surface features at various resolutions. A new radar system in the
millimeter wave-band has now been demonstrated with a resolution of <1m. This MMW-radar was deployed in a
nested configuration with an X-band marine radar from a beach near Faro in Portugal. The results from the two
systems show how the MMW-radar can image fine detail surf zone and swash processes to a range of O(200m),
while the marine radar provides lower resolution images of O(10m) to longer ranges of O(2km). Data from the two
nested radars are shown from a recent deployment on a barrier beach in the Ria Formosa region of the Algarve,
Portugal. The data from these nested radars are analysed to map wavelengths in 2-D and a non-linear bathymetric
inversion is used on both sets of data to estimate the bathymetry of the imaged area. Comparisons with in-situ
surveys demonstrate the accuracy of this technique.