Ocean Gyres and Hurricanes

This animation was done by NASA/JPL’s computational model ECCO2 (Estimating the Circulation and Climate of the Ocean, Phase II). It’s a high resolution model of global ocean circulation. It can resolve ocean eddies and other narrow-current systems that transport heat and carbon. ECCO2 simulates ocean flows at all depths, but only surface flows are shown in this visualization. Video credit: NASA/Goddard Space Flight Center Scientific Visualization Studio.

You can see the full (3:02) simulation, including the other oceans around the planet, on YouTube.

The main driver of currents in the Atlantic Ocean is the Gulf Stream. As you can see, it spins off several gyres along its periphery that wander around but are fairly persistent. Also of note, as you approach the equator the gyres disappear due to lack of any significant Coriolis force.

The fact that these gyres are fairly persistent creates temperature anomalies in the water, especially in the Gulf of Mexico. Because the water circulates in a closed loop and doesn’t mix much with surrounding water, it will warmed by the sunlight to temperatures that can be several degrees higher than surrounding waters. Take a look at this map (which can take a while to load) and you’ll see a strong correlation between water temperature and gyre location.

Here’s a screenshot of one frame in that ECCO2 simulation. Gyres have been highlighted in red to indicate warmer water temperatures. These pockets of warm water are concentrated in the Gulf and Caribbean, but there are two that persist along the mid-Atlantic coastline:

Recent research has shown a link between ocean gyres and rapid intensification of hurricanes, where wind speeds increase by over 35 mph in a 24 hour period. The fuel for hurricanes is warm water and moist air:

So any hurricane that tracks over a warm gyre will get a boost in intensity. It’s only with this recent research that the connection between gyres and hurricanes has been made. Once incorporated into computational weather models this will allow meteorologists to better anticipate rapid intensification — something that currently eludes prediction and has lead to devastating underestimates of hurricane damage, as was the case with:

  • King (1950) – Increased 60 mph in 24-hours
  • Humberto (2007) – Increased 65 mph in 24-hours
  • Laura (2020) – Increased 45 mph in 24-hours
  • Ida (2021) – Increased 60 mph in 24-hours
  • Idalia (2023) – Increased 45 mph in 24-hours

All these hurricanes had devastating consequences that could have been mitigated with more accurate predictions. Whether we can do much about climate change is still an open question. But what we can do is learn how to better predict the consequences of climate change. As new science emerges, we’ll have more tools in our arsenal.

Perhaps gyres might be the ideal locations to deploy bubble curtains to mitigate hurricane intensification, rainfall amounts, and wind speeds. Gyres are typically hundreds of miles in diameter, and would require a massive fleet of ships, or an underwater network of pipes, to cool that much water. But it may be cost-effective considering the damage those hurricanes wrought. A cost analysis is included in that bubble curtain link.

Improving our computational weather models is an ongoing effort. Computing power keeps increasing, and the theoretical models keep improving. New science like this gyre research is what drives the evolution of climate models. And better models mean more accurate forecasts.

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