TIDAL

The objective of this project was to set up, demonstrate, and assess a prototype service providing tidal information (water level and currents) based on assimilated altimeter-derived tidal constants. The user community  consists of both port authorities and private companies. A representative of the user community was involved in defining the user requirements, and in the validation and dissemination of the results.

Users required information for selected time periods and locations worldwide on tidal heights and current speed and direction for their planning and operations (dredging, pipe laying, consultancy, survey, oil and gas, science, administration). They wanted the information products to be generated, viewed and downloaded interactively, and to be presented as time series and as statistics (histograms, exceedence tables, scatter tables).

In the system development and implementation phase the on-line system required to deliver the information products was defined and a proto-type produced. Data was input for three service case areas carefully selected to provided different degrees of coastal station coverage. These areas were the Flemish coast, Celebes Sea and the Rio de la Plata Estuary. Results were generated for the three case study areas.

Finally, the on-line service and product accuracy and reliability were tested for the three case study areas. In the Southern North Sea and Rio de la Plata User Cases tidal computations were compared with in-situ measurements. The tidal products were within specification and fit for use. In the Celebes Sea User Case computed tidal constants were compared with constants that were obtained by interpolating measured constants in neighbouring harbours. The model results were far superior.

The service demonstrated the integration of the following types of data in a global tidal assimilation model: digital sea bottom topography maps for coastal areas, global tidal constants from altimeter data, fixed position and localised coastal station measurements.

The prototype service led to the development of a commercial, Internet-based tidal information service with world-wide information retrieval capability: www.tidal-info.com