Small uncrewed drones will be flown into hurricanes this season, capturing data that should help improve the accuracy of hurricane intensity forecasts.

The United States National Oceanographic and Atmospheric Administration (NOAA) has been flying crewed aircraft into and above hurricanes for decades. These ‘hurricane hunters’ – effectively research stations with wings – provide important observations that feed into hurricane analyses and forecasts.

Hurricane observations come directly from the hurricane hunter aircraft themselves and from external instruments launched from the aircraft once inside a cyclonic storm. However, one area of the atmosphere that is notoriously tricky to sample during a hurricane is the ‘marine boundary layer’ – the lowest section of a hurricane where the atmosphere directly interacts with the ocean’s surface.

The marine boundary layer is a violent and turbulent zone where it’s not safe to fly crewed aircraft. This part of a hurricane can only be sampled remotely, using instruments such as dropsondes – small capsules that get launched from an aircraft and collect data as they slowly parachute towards the surface – and uncrewed surface vehicles (USVs) that capture measurements from above and below the water at the same time.

Despite the use of dropsondes, USVs and other uncrewed instruments, observations from inside the marine boundary layer are sparse during a hurricane.

Image: Radar display from a NOAA hurricane hunter aircraft in the centre of Tropical Storm Idalia in August 2023. Source: NOAA / Nick Underwood.

To help fill this data gap, a small uncrewed aircraft system (sUAS) will collect observations of pressure, temperature, humidity and wind from within the marine boundary layer. These near-surface observations will be integrated into NOAA’s hurricane model to help improve its forecast accuracy.

The sUAS will be launched from NOAA hurricane hunter aircraft before dropping to lower levels of the hurricane to collect observations near the surface. While these drones were successfully tested in past seasons, this will be the first time data from the sUAS drones will be integrated into NOAA’s forecast model.

Experiments suggest that the use of sUAS drones could improve hurricane intensity forecasts by up to 10%, and tropical storm intensity forecasts by up to 25%.