A System for Using Radar to Record Wave Direction

摘要

A radar system provides images of waves in the coastal zone to obtain wave direction information is described. The heart of the system is an X-band marine radar which operates at 9,375 megahertz with a 3-centimeter wavelength and a 0.05-microsecond pulse width. The records are accumulated by photographing the plan position indicator (PPI) scope. The system is designed for unattended operation and includes an automation unit that activates the radar at preset times, usually at 2-hour intervals. A sequence of one to nine photos is obtained on each of four ranges after which the system turns off until the next scheduled observation. Wave images show single and multiple long-crested wave trains permitting observation of wave refraction and shoaling. The information content in the radar images is similar to that in aerial photos. However, radar images can be collected at night, during overcast, and in light rain conditions. Radar imagery is more limited than aircraft imagery in geographical coverage and in the quality of the imagery. Good agreement was found between estimates of wave direction and length obtained with radar and those obtained with other observational techniques. (Author)