Hurricane forecasting has come a long way, but not far enough for Steven Businger.
The University of Hawaii professor says there has been no significant improvement in the ability of forecasters to accurately predict changes in the strength of hurricanes in at least 20 years.
The problem, Businger says, is that there are some key data found at the core of these powerful storms that are missing from the models used to predict the behavior of hurricanes.
That’s where Businger comes in. Through the development of storm balloons and the collection of long-range lightning data, he is working to extract that information and ultimately take hurricane forecasting to a new level.
Businger, chairman of UH’s Atmospheric Science Department, recently traveled to Parker, Colo., home of the Jonathan Merage Foundation, a $25,000 funder of his latest research, to test the newest generation of storm balloons in a local thunderstorm.
“It went better than expected,” he says of that day in June. “It was really a lot of fun.”
It was a bright sunny morning on a day with a thunderstorm in the forecast. When it was time to launch the balloon, the storm rolled in just in time.
The 10-foot-diameter latex balloon equipped with GPS and weather-tracking instrumentation flew up and around and into the storm, the altitude controlled remotely using ballast adjustments and helium releases. Dodging lightning, rain and hail, the balloon eventually was retrieved with a full data set.
“It was quite amazing,” he says.
Businger, a pioneer in storm balloon development, has been working with balloons for 25 years. Not every flight attempt has gone as planned. In 2005 he was part of a team that traveled to Puerto Rico intending to launch storm balloons into a hurricane. That year, however, no big storms came close to Puerto Rico.
Businger, leader of the Storm Evolution and Energetics Research group at UH, says the development of storm balloons has advanced over the years with the help of new technology. The balloons also have become more affordable.
“They can be pretty tough,” he says, especially if they are encased in a lightweight, durable material such as Spectra fiber.
Although hurricane track forecasting has improved significantly in recent decades, the accuracy of hurricane intensity forecasts has remained about the same.
In a move to make some headway in intensity forecasting, Businger is aiming to fly storm balloons at low levels into a hurricane in hopes of recording crucial data about the energy exchange between the storm and the ocean surface. That exchange of heat, moisture and momentum determines how hurricanes strengthen and intensify.
With better mapping of the water vapor and heat associated with condensation of water in hurricane storm clouds, forecasters should be able to better predict the strength of the storms, he says.
Currently, NOAA’s hurricane hunter airplanes are unable to fly below 5,000 feet due to the extreme turbulence between the ocean and atmosphere.
Instead, the aircraft now deploy “dropsondes,” lightweight cylindrical tubes with a parachute and global positioning system technology.
The problem with dropsondes is the coverage is limited. They essentially obtain vertical profiles of a storm at fixed points only, Businger says.
“The data is lacking,” he says bluntly.
Despite this summer’s successful test flight, Businger says there’s more to be done before researchers can fly the latest generation of storm balloons into the heart of a hurricane.
He says more work is needed to better weatherize the instrument package, in maintaining constant volume of the balloon and in implementing a two-way satellite communication system.
He’s hoping those shortcomings can be addressed to allow launching during the next hurricane season.
In a separate but related project, Businger has received $100,000 in funding from the Merage Foundation to continue his work on long-range lightning detection, which has been shown to be effective in real-time storm tracking, warning and immediate forecasting.
Lightning can be detected 10,000 miles away by receivers that are part of a ground-based lightning location system developed by the professor.
Businger says the way the lightning data are ingested into the hurricane model will be refined over time to provide a more sophisticated and balanced approach that improves the way in which individual storm clouds evolve in the model.
As part of the study, a number of poorly forecast recent hurricanes will be examined as case studies to help prod improvement in hurricane simulation and prediction.
