Hurricane formation triggered by very small disturbances

While investigating how hurricanes develop, Florida State University researchers have found that even a slight atmospheric disturbance can trigger a hurricane. A better understanding of hurricane formation will help meteorologists predict these storms and give the public more time prepare for them.

“The whole motivation for this paper was that we still don’t have that universal theoretical understanding of exactly how tropical cyclones form, and to really be able to forecast that storm-by-storm, it would help us to have that more solidly taken care of,” said study co-author Jacob Carstens.

Existing theories on hurricane formation propose that some sort of disturbance is what sets in motion the development of a storm. To investigate how these disturbances arise, Carstens used mathematical models to project hurricane formation beginning with the simplest conditions.

“We’re trying to go as bare bones as possible, looking at just how exactly clouds want to organize themselves without any of these external factors playing into it to form a tropical cyclone more efficiently,” said Carstens. 

“It’s a way we can further round out our broader understanding and look more purely at the actual tropical cyclones themselves rather than the surrounding environment’s impact on it.”

The simulations started with stable conditions, and then the researchers added a very small amount of random temperature fluctuations. 

As the thermal radiation interacted with water vapor and other factors, the simulated clouds formed into clusters that circulated through the atmosphere. 

The experts repeated the model at simulated latitudes between 0.1 degrees and 20 degrees north, a range that includes the latitudes where tropical cyclones typically form. This range also includes latitudes very close to the equator where hurricane formation is rare.

The study revealed that every simulation in latitudes between 10 and 20 degrees produced a major hurricane. The first sign of a vortex emerged well above the surface and affected its surrounding environment, giving rise to a hurricane a few days later.

A better theoretical understanding of hurricane formation will help meteorologists recognize the conditions that could trigger a storm, improving forecasts and helping people prepare for dangerous weather. 

“It’s becoming ever more important in our field that we connect with emergency managers, the general population and other local officials to advise them on what they can expect, how they should prepare and what sorts of impacts are going to be heading their way,” said Carstens. 

“A more robust understanding of how tropical cyclones form can help us to better forecast their location, their track and their intensity. It really goes down the line and helps us to communicate sooner as well as more efficiently and eloquently to the public that really needs it.”

The study is published in the Journal of Advances in Modeling Earth Systems.

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By Chrissy Sexton, Earth.com Staff