Researchers at the Massachusetts Institute of Technology propose a way to forecast the destructive potential of a hurricane : listening to a storm underwater.
In a paper to be published in Geophysical Research Letters, Nicholas C. Makris and a former graduate student report a strong correlation between the intensity of sound recorded by an undersea microphone in the mid-Atlantic and the wind power of a hurricane that passed over it. They say that such microphones, known as hydrophones, could be a safe and relatively inexpensive means of estimating hurricane force.
Dr. Makris and Joshua D. Wilson worked out the theory of underwater acoustic monitoring of storms in a 2005 paper. “To be very frank with you, it’s a mystery” what makes storms noisy underwater, Dr. Makris said. The most popular idea currently is that it has something to do with oscillating air bubbles.
The researchers then went looking for empirical data to back their theory, and found it from a hydrophone placed at a depth of 762 meters by the National Atmospheric and Oceanic Administration. It happened that Hurricane Gert passed over the area in September 1999, and a hurricane-hunter plane measured the wind speed at the same time.
The hydrophone data showed sound intensity rising when the storm’s outside wind “wall” passed over, and again when the inside wall, the most destructive part of the storm near the eye, passed over. “We got a beautiful correlation,” Dr. Makris said . Dr. Makris is conducting additional experiments, working with the Mexican Navy off the west coast of Mexico.

HENRY FOUNTAIN