Hurricane hunters are flying through Ian's powerful winds to get the forecasts you rely on – here's what happens when the plane plunges into the eyewall of a storm | Science & Technology News

We need instruments that not only measure the atmosphere but also the ocean. The winds can steer a storm or tear it apart, but the ocean heat and moisture are its fuel.

We use dropsondes to measure temperature, humidity, pressure and wind speed, and send back data every 15 feet or so all the way to the ocean surface. All of that data goes to the National Hurricane Center and to modeling centers so they can get a better representation of the atmosphere.

One P-3 has a laser – a CRL, or compact rotational raman LiDAR – that can measure temperature, humidity and aerosols from the aircraft all the way down to the ocean surface. It can give us a sense of how juicy the atmosphere is, so how conducive it is for feeding a storm. The CRL operates continuously over the entire flight track, so you get this beautiful curtain below the aircraft showing the temperature and humidity.

The planes also have tail doppler radars, which measure how moisture droplets in the air are blowing to determine how the wind is behaving. That gives us a 3D look at the wind field, like an X-ray of the storm. You can’t get that from a satellite.

We also launch ocean probes call AXBTs – aircraft expendable bathythermograph – out ahead of the storm. These probes measure the water temperature down several hundred feet. Typically, a surface temperature of 26.5 degrees Celsius (80 Fahrenheit) and above is favorable for a hurricane, but the depth of that heat is also important.

If you have warm ocean water that’s maybe 85 F at the surface, but just 50 feet down the water is quite a bit colder, the hurricane is going to mix in that cold water pretty quickly and weaken the storm. But deep warm water, like we find in eddies in the Gulf of Mexico, provides extra energy that can fuel a storm.

This year, we’re also testing a new technology – small drones that we can launch out of the belly of a P-3. They have about a 7- to 9-foot wingspan and are basically a weather station with wings.

One of these drones dropped in the eye could measuring pressure changes, which indicate whether a storm is getting stronger. If we could drop a drone in the eyewall and have it orbit there, it could measure where the strongest winds are – that’s another important detail for forecasters. We also don’t have a lot of measurements in the boundary layer because it’s not a safe place for a plane to fly.

The Cabo Verde Islands are in the Atlantic’s hurricane nursery. The seedlings of hurricanes come off Africa, and we’re trying to determine the tipping points for theses disturbances to form into storms.

Over half the named storms we get in the Atlantic come from this nursery, including about 80% of the major hurricanes, so it’s important, even though the disturbances are maybe seven to 10 days ahead of a hurricane forming.

In Africa, a lot of thunderstorms develop along the Sahara desert’s southern border with the cooler, moister Sahel region in the summer. The temperature difference can cause ripples to develop in the atmosphere that we call tropical waves. Some of those tropical waves are the precursors for hurricanes. However, the Saharan air layer – huge dust storms that come rolling off Africa every three to five days or so – can suppress a hurricane. These storms peak from June to mid-August. After that, tropical disturbances have a better chance of reaching the Caribbean.

At some point not too far in the future, the National Hurricane Center will have to do a seven-day forecast, rather than just five days. We’re figuring out how to improve that early forecasting.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Jason Dunion, University of Miami. The Conversation has a variety of fascinating free newsletters.

Jason Dunion receives funding from NOAA, NASA, and the Office of Naval Research.