Underwater gliders improve hurricane forecasts

Assistant professor of marine sciences Catherine Edwards, with colleagues at the UGA Skidaway Institute of Oceanography and the University of South Florida has developed and deployed autonomous underwater gliders to improve the accuracy of hurricane forecast models:

The 2018 hurricane season provided Edwards and her colleagues a fortuitous opportunity to demonstrate the value of glider data. Edwards deployed two gliders in advance of Hurricane Florence. One was launched off the North Carolina coast and the other farther south, near the South Carolina-Georgia state line. The gliders discovered the models’ ocean temperature forecasts were significantly off target. Edwards points to charts comparing the predictions from ocean models run in the U.S. and Europe with the actual temperatures two days before Florence made landfall.

On the south side of the storm path, the models predicted that the ocean had a warm, slightly fresh layer overtopping cooler, saltier water below, but the glider revealed that the water column was well-mixed and overall, warmer and fresher than predicted. On the north side of the storm, the models predicted warm, well-mixed water, but the glider detected a sharp temperature change below the surface, with a much cooler layer near-bottom. However, the most surprising part was just how stratified the water was.

More than a unique view

“There is almost a 14-degree Celsius (approximately 25 degrees Fahrenheit) error that the glider corrects in the model,” she said. “The model and data agree near-surface, but the models that don’t use the glider data all miss the colder, saltier layer below. The model that incorporated glider data that day is the only one that captures that vertical pattern.”

Not only can gliders provide a unique view of the ocean, they fly on their own, reporting data regularly, before, during and after a hurricane, making them a powerful tool for understanding the effects of storms.

“The glider data is being used in real time,” Edwards said. “These real time observations can improve our hurricane forecasts right now, not just in a paper to be published a year from now.”

Great work by researchers in a optimal location to better understand the coast the immediate off-shore conditions during hurricane season. The monitoring system brings together a variety of technology and expertise to the improve forecasts, putting the multidisciplinary expertise of faculty at the forefront of protecting people and property.

Image: Catherine Edwards examines the tail assembly of a glider