instrumentation advancements. Indeed, a recent conference of 

 scientists and engineers skilled in wave measurement cited the 

 improvement of the measurement, analysis, and reporting technology of 

 directional wave spectra as the first priority of future ocean wave 

 research and development (Dean, 1982). 



Some directional wave data are available today using both 

 remote sensing and in- situ techniques. Remote sensing, a promising 

 alternative for the future because of its capability to monitor large 

 ocean surface areas, presently suffers from the expense and lack of 

 availability of air and space craft platforms as well as sometimes 

 lengthy and expensive data analysis. Further, the development of 

 remote sensing still requires dependable ground verification. 

 Although in- situ systems are single point sensors, they offer some 

 advantages over remote sensing techniques. In- situ instruments can 

 monitor the sea surface continuously, are composed of less expensive 

 and less complex hardware, and can generally offer relatively 

 inexpensive data reduction that approaches real-time. Although more 

 difficult to install and service, submerged in- situ systems offer 

 advantages over surface riding or piercing instruments in that 

 submerged hardware is less prone to loss, does not interfere with the 

 propagating wave field, and is more likely to operate without 

 malfunction during extreme wave events. Such underwater systems, 

 however, are generally limited to use in near-shore applications or 

 at a shallow depth from a fixed platform in deep water. 



