The Liverpool Bay Coastal Observatory, constructed by the Liverpool-based National Oceanography Centre (NOC), previously the Proudman Oceanographic Laboratory (POL), aims to integrate (near) real-time measurements with coupled models into a pre-operational coastal prediction system. The extensive assembly of data from tidal gauges, satellites, instrumented ferries and X-band radar has now been joined by a pair of WERA HF radars based near Formby and Abergele.
Seaview Sensing software is being used to provide metocean data from the WERA system. Seaview software was chosen for this application because of the requirement to measure waves in realtime.
This system differs from other WERA installations in that some of the signal processing has been provided by Neptune Radar Ltd who also provide maintenance and support services to POL.
Liverpool Bay is adjacent to the UK's densely populated North-West conurbation of Liverpool and contains the important Port of Liverpool handling some 32 million tonnes of cargo (including 11 million tonnes of oil) each year. The relatively shallow bay has been chosen as the location for four offshore wind farms planned to provide electricity for 400,000 homes.
The shallow water and large tidal range of the bay provides a challenge for the extraction of wave data from HF radar, since the finite-depth dispersion relation used in the inversion is increasingly sensitive to errors as water depth decreases. To mitigate this effect the inversion uses tidal corrections provided by POL's own tidal model.
Further information on the Coastal Observatory can be found here, with live data from the HF radars available here. Data at midnight and midday daily can also be seen on the Seaview Data Viewer. We have demonstrated that it is necessary to increase the averaging of radar data before extracting wave information. This has been implemented and is being tested on the Liverpool Bay system and the data can be seen on a separate data viewer.