While NOAA has made steady progress in forecasting the track of a hurricane, forecasting hurricane rapid intensification (wind speeds increasing 35 mph in 24 hours or less) remains a big challenge. To improve understanding of hurricane rapid intensification, scientists need to understand the ocean processes that are occurring as intensity increases, which means collecting data immediately before and during a storm.
In July 2021, NOAA and Saildrone deployed five Explorer uncrewed surface vehicles (USVs) equipped with ruggedized “hurricane wings” designed especially for operating in winds over 90 mph and waves over 50 feet. The goal of the mission was to measure near-surface atmospheric and upper-ocean parameters to calculate energy and momentum fluxes between the atmosphere and ocean outside and within hurricanes. The observations collected would be used to understand how ocean-atmosphere interaction affects hurricane intensity and improve hurricane prediction models.
The vehicles were strategically positioned in five operational areas that have a high likelihood of encountering a hurricane, based on historical track data. NOAA and Saildrone Mission Control worked together to task the vehicles into as many storms as possible.
The USVs transmitted meteorological and oceanographic data including air temperature and relative humidity, barometric pressure, wind speed and direction, water temperature and salinity, sea surface temperature, and wave height and period from the eastern tropical Atlantic in near real time; the NRT data was used to improve ocean-atmosphere initial conditions in forecast models.
The mission also sought to pair the USVs with underwater gliders to measure the coupling between the surface atmosphere and upper ocean.
NOAA 2021 Hurricane Mission Webpage