Wirewalker: An autonomous wave-powered vertical profiler

An inexpensive vertically profiling float that draws its energy from the oc ean surface wavefield is described. Termed the "Wirewalker,'' it is a gener alized platform capable of supporting a variety of self-contained instrumen ts. The motion of the waves drives the positively buoyant profiler downward . It then free floats upward, decoupled from the surface motion field. The design focuses on mechanical simplicity and low cost. In moderate sea state s, a prototype Wirewalker has completed profiles to depths of 60 m every 15 min. Profiles from the surface to 50-100 m can be obtained rapidly enough that diel and higher-frequency variability can be resolved.