Day 2: Beginning to Understand RaDyO

If you’ve ever been snorkeling or even owned a fish tank, you may have noticed that from under the water, you can see submerged objects quite clearly – but if you look up, you cannot see above the water. Light dances on the water’s wavy surface and a complex combination of chemicals, microorganisms, and water absorb, scatter, or photosynthesize the light, complicating the way a viewer or camera interprets the images.

The archer fish has learned to look up perfectly in calm waters. Found in both fresh and salt waters of Australia, India, the Philippines, and Polynesia under the roots of mangroves, the eyes of the archer fish compensate for the refraction of light hitting the water, enabling adult fish to spit water at unsuspecting insects with precise accuracy.

But out on the ocean, complex waves complicate the problem of viewing images that are above the water from below. So one cloudy Monday morning in September, 2008, head scientist Tommy Dickey and his team of scientists set out aboard the Kilo Moana to measure the optical properties of ocean waves. The Kilo Moana is a large swath hull ship with a stable platform designed for oceanographic research. It measures 186 feet long, or about half the length of a football field. Dolphins play in the Hawaiin vessel’s tail waves as it sets out toward its destination, about eight miles south of Carpenteria, California, near the Santa Barbara Channel Marine Reserve, and one mile away from the famed Floating Instrument Platform, or simply “FLIP.”

This 100 meter-long platform, used by Scripp’s Institute of Oceanography (SIO), is towed out to sea in a horizontal position, then actually flips upright, using its low center of gravity that extends under the water. FLIP is very stable, making it an ideal place for taking wave measurements. The FLIP is a bizarre piece of oceanographic equipment that, in the words of the SIO FLIP website, features “doors in the floor, portholes in the ceiling, tables bolted sideways to walls, [and] stairs leading to nowhere!” Dickey and his colleagues used FLIP for another experiment called the Optical Dynamics Experiment, or ODEX, under ONR funding (like RaDyO) back in 1982.

Dickey and his team chose this location near FLIP as a benign place with low winds and small waves. These mild conditions contrast to the second part of the experiment, to take place in August of 2009 just north of Hawaii, where high winds, high seas, and blue waters mark a starkly different environment. Here, south of Carpenteria, the Kilo Moana floats in well-sampled waters, where historical and routine physical, biological, and optical data can compliment the research that Dickey and his team are doing. Plankton thrives in these waters relatively close to shore, giving the ocean a green tint.

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