A new family of real-time wave and tide instruments

A series of compact, intelligent instruments were developed as a low-cost solution to the needs of marine scientists and engineers for measurement of nondirectional wave characteristics as well as tides. The design of these instruments varies from a pressure sensor connected to a laptop PC to a self contained instrument consisting of a precision silicon-on-sapphire pressure sensor, 32 bit microprocessor, and flash memory. In the first case the data collection and wave analysis are controlled by software running on the remote computer. In the second case, the same wave processing algorithms are contained in firmware of the internal 32 bit microprocessor. The instruments output one minute tide averages, wave statistics, and 62 spectral surface energy components for wave periods from 3 seconds to 30 seconds. A description of the instrument design is presented along with the theory of operation and a discussion of the algorithms chosen for the processing of the wave statistics. The mooring arrangements used off the San Diego coast for inter comparison studies is described. Two of the new instruments were deployed along with an S4ADW directional wave current meter. The data and processing methods from all three instruments are compared to the wave statistics data obtained from the single-point wave gauge located at the Scripps Pier in La Jolla, CA which is installed and operated under the Coastal Data Information Program by the Scripps Institute of Oceanography