NOAA To Use Drones To Help With Hurricane Forecasts
Following the most active hurricane season in history, hurricane forecasters are testing the use of drones to improve the accuracy of storm predictions.
By sending them into the most violent and previously unreachable parts of hurricanes, NOAA is working to get a more complete picture of what a hurricane is doing at the altitudes that cause inland damage.
How Storm Information Has Been Collected
Currently, Hurricane Hunter aircraft and their intrepid crews fly into and above the eye of a hurricane to take readings of wind speeds, wind directions, and air and water temperatures. The Hurricane Hunter usually stays at 5,000 feet or above, and most of its storm data is collected between 8,000 and 12,000 feet.
The eyewall of a hurricane (as opposed to the calm eye) is an unpredictable and violent place with fifty-foot waves, winds over 100 miles an hour, and spraying saltwater that could corrode data-collecting instruments and airplane engines.
The boundary layer of a hurricane, the ocean surface layer to 4,000 feet high, is so treacherous that the aircraft won’t even try to fly through it. Two factors reflect the importance of collecting data in the boundary layer: people along the coast live at sea level, not above 8000 feet where most data is collected, and hurricanes get their energy from the ocean at its surface. Understanding how this energy transfer occurs and affects conditions at ground level is critical to forecasting the storms’ ferocity and danger.
The Hurricane Hunter aircraft have been deploying devices called dropsondes to help gather data at sea level, but they are limited in the amount of area they can cover. These single-use, 9-pound canisters are released into a storm from around 10,000 feet and deploy a parachute so they can take data readings for up to one hour as they fall, eventually landing in the ocean. Their 20-mile transmission limit, however, isn’t sufficient for hurricanes that often span hundreds of miles, presenting a wide variety of conditions from one edge to another.
How Drones Will Improve Data Collection
NOAA is testing three Altius 600 unmanned drones that can fly for hours inside a storm’s eyewall at the lowest levels. These drones weigh 25 pounds and have a wingspan of 9 feet. They are either pre-programmed or piloted by the Hurricane Hunter crew.
Like the dropsondes, the drones are launched from the plane. Their advantages start here. They can fly up to 200 miles away, stay airborne for four hours, and pass through a hurricane’s eyewall multiple times at low altitude while gathering data. NOAA’s goal is to use the drones primarily at the lowest hurricane levels, about 1,000 feet above the ocean surface, where the conditions mimic what most people would experience when the storm makes landfall.
Test flights to date have been successful, including a clear-weather test in Maryland last month. NOAA plans to deploy up to four drones during the 2021 hurricane season. As more data from the drones amasses over the next two years, modeling a storm’s predicted track — those so-called spaghetti models — should become more accurate.
Other Posts of Interest:
Sources: South Florida Sun Sentinel, NOAA, ofcm.gov