As good as scientists have gotten at tracking and predicting the force and path of tropical storms and hurricanes, we are still often surprised by a change in course or intensity. There have been monster storms that, while we knew they'd be big, we weren't prepared for just how much damage they inflicted. On the other hand, coastal towns have braced for the worst just to see a storm fizzle or change direction.
Scientists believe that the secrets to the strength and duration of these storms lies in the ocean and for the past few years organizations like Woods Hole Oceanographic Institution (WHOI) have worked with NOAA to deploy underwater gliders to collect data on ocean conditions during hurricane season.
The gliders measure water temperature, salinity and density before, during and after the storm. As Hermine made its way up the East Coast, WHOI scientists deployed several gliders 100 miles offshore of Massachusetts along the continental shelf where they dropped to 100 to 300 feet below the surface to collect data.
The traditional approach of aircraft flying above and through the eye of a storm to take measurements is missing many pieces of the puzzle.
“When Hurricane Irene hit New Jersey and New York, we had a pretty good idea of where the storm was headed in advance,” said WHOI physical oceanographer Glen Gawarkiewicz, “we just didn't know how strong they'd be when they made landfall. One of the reasons it's so hard to forecast is that intensity depends on sea-surface conditions directly ahead of and below the storm. Gliders and other new instruments we are testing enable us, for the first time ever, to make measurements in these very harsh conditions.”
The gliders can continually take measurements from weeks before the storm, through the worst conditions and for weeks after, something that human operated aircraft can't safely do. The gliders are remotely operated from land and send data back in real time via satellite.
The scientists say the most important data for predicting intensity is water temperature -- if the storm churns up a lot of deep colder water to the surface, the intensity will decrease. Consistent water temperature data during hurricane season could significantly improve predictions and help coastal towns know when to prepare for the worst or when to just expect a big storm.
Hermine was an especially good storm to survey with the gliders because it moved slowly along the New England coast, giving the gliders a longer time to gather data. The gliders remain in the ocean for weeks after the storm, taking measurements to that can predict future weather.
The researchers say the data from Hermine will take months to analyze, but they're exited to see what secrets they can uncover. For example, the storm drifter farther west than scientists thought it would and the data collected by the gliders could tell us why.