Into the belly of the beast
While most of us hid from Hurricane Gonzalo, BIOS glided right into the belly of the beast.
Its scientists were able to gain insight into the monster storm, with help from a scientific ocean glider they named Anna.
Its ability to gather information on salinity, temperature and current speed of the deeper ocean is changing the future of weather forecasting.
“We didn’t have time to launch it during Tropical Storm Fay,” said Ruth Curry, a physical oceanographer at the Bermuda Institute of Ocean Sciences, “but we know the deep water temperature just before Fay was 82.4F. We launched just after Fay and the temperature had dropped by about four degrees. We know from readings during Hurricane Gonzalo that the deeper ocean temperature was still at this cooler temperature when Gonzalo approached. That caused Gonzalo to drop to a category three force storm and then a category two just as it struck us. Tropical Storm Fay really saved our skins.”
Anna was launched five miles off St David’s Head.
It measures 6ft long and 1ft wide and can be operated remotely. It dives, surfaces, sends data back to base through a satellite transmitter and then propels itself forward before diving again. During Gonzalo, the glider travelled 50 miles southwest of Bermuda.
According to Curry, scientists could only take measurements from fixed moorings in the past, and those measurements were at a very limited ocean depth.
Anna is able to travel to the area that partly fuels and directs tropical storms and hurricanes — between 200ft and 500ft.
“The gliders give us an unprecedented view of what happens under the ocean during a storm,” Curry said. “There have been a few other opportunities. A Rutgers University group measured Hurricane Irene two years ago, and gliders were also released during Hurricane Sandy in 2012. Rutgers were able to document the fact that Sandy’s forecasted intensity and track was off because weather forecasters didn’t have the ocean heat content right. Now, there is a fair amount of focus on improving that part of hurricane forecasting.”
Curry said data collected by the BIOS glider was “phenomenal”. For example, it recorded underwater waves of 150ft — a staggering height.
“This is a signature of a huge amount of energy,” she said. “That really mixes up the salinity of the ocean.”
BIOS collected the glider from the ocean on Monday.
“It was still rough out there,” said Curry. “The waves were going in one direction and the wind in another.”
The glider did very well during the storm, but its rudder was sheered off during the height of Gonzalo. That meant it could still dive and come to the surface but couldn’t be steered remotely.
Already, there has been great interest in information collected by BIOS’ glider. The Weather Channel has interviewed Curry twice in the past week, about the glider’s findings.
“There is enormous interest,” she said. “I have already been contacted by colleagues at the National Hurricane Centre, Rutgers University and Woods Hole Oceanographic Institution in Massachusetts. I am new at storm research so I will be collaborating with other oceanographers to analyse the data.”
She is also hoping to give a public talk in Bermuda in the coming weeks about her findings.
“Launching during a direct-hit hurricane like Gonzalo, which was a category four as it approached us, is the Holy Grail of ocean science,” she added.
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